Ten Things I Like About... Podcast

Caecilians: Conservation

Summary: Even though we don’t know much about caecilians they still need our help. Join Kiersten as she talks about what threats caecilians face and how we can help.
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes: 
IUCN Red List: www.iucnredlist.org
“Fatal fungus found in third major amphibian group, caecilians,” by Natural History Museum, Phys Org; phys.org/news/2013-05-fatal-fungus-major-amphibian-group.html
Chytridiomycosis: Cornell Wildlife Health Lab: cwhl.vet.cornell.edu
Conservation Organizations:
IUCN SSC Amphibian Specialist Group: www.iucn-amphibians.org
Amphibian Ark: www.amphibianark.org
Save the Frogs: savethefrogs.com
Association of Zoos and Aquariums: www.aza.org/amphibian-conservation
 
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode concludes caecilians and the tenth thing I like about these intriguing creatures is the conservation efforts we already have under way to protect their future. 
Throughout the last nine episodes I have clearly established that we don’t know as much about these fascinating amphibians as we should considering how long they’ve been on the planet. Of course, they are fairly secretive living underground and under the water, so it’s definitely been hard to study them. Having said this, you may be wondering how do we know anything about their conservation status if we can’t get an accurate count of how many are in the wild. The answer is, we can’t, but we do have enough information on some of the species to classify them on the IUCN red list of threatened species.
As a reminder, or for the first time if you haven’t listened to any of my previous series’, the IUCN stands for International Union for Conservation of Nature and Natural Resources. They list the conservation status of animals and plants from around the world. A species can be listed as data deficient, which means we don’t have enough information to make a decision on whether the population is so low that the species is in danger of disappearing, or extinct, which means all the individuals of that species have died. They no longer exist. 
There are several stages in-between data deficient and extinct. These classifications help us develop plans to help species survive the changing environment that is most often impacted by human activity.
Of the 200 species of caecilians that we know about, 193 are listed on the IUCN’s red list. 76 are listed as Least Concern which is good, that means their populations are healthy and thriving. 3 are listed as Near Threatened which is a step up from Least Concern, which means they are still okay for now but we should start including them in conservation plans. 7 are listed as Vulnerable which means they are one step away from Endangered and need help now. 16 are listed as endangered which means if efforts are not taken now we could lose this species. And 2 are listed as critically endangered which means they are a step away from extinction. That leaves 89 listed species as Data Deficient, almost half of the known species of caecilians.
Now that we have the numbers, we have to ask what is impacting caecilian populations. I think you, my listeners, may be able to guess. According to the IUCN website habitat loss is the biggest impact on caecilian populations. It’s the subtropical and tropical species that are being disturbed the most and the activities that are impacting them are all human centric activities. Non-timber agriculture is the largest pressure on the habitat in which our most endangered caecilians are found. The pesticides used in association with the agriculture is the next threat to their lives. Since they live in the ground and are dependent on mainly insects for food you can see how they would be majorly impacted by these activities.
So what exactly are we doing to help? The first thing is we’re still studying them. The more information we have about how they live and where they live the better our conservation plans. We have to know what habitat is best for them, what they eat, and how long they live to truly understand how to successfully protect them. Studying their natural history is a great tool for any conservation efforts for their future. Any students or zoologists out there listening that are looking for a species to study, maybe you can think about caecilians.
Studying animal’s in situ, which means out in their natural habitat, can be difficult. First you need to find them, then you need to catch them without harming them, then you measure everything you can possibly measure such as weight, length, color, sex, and any distinguishing characteristics such as scars or patterning. Then before you let them go you tag them with some kind of ID tag that does not harm they, so if they are captured again or seen by naturalists data can be added to their history. For example, when ornithologists catch birds they place a ring around their leg that has a number on it specific to that bird. When that bird is found again or birders report seeing the bird that information is added to their file. This helps us understand how large an animal’s home territory my be, determine migration paths, and can tell us how long they live. 
Caecilians are even more difficult than most because they choose to live underground or underwater making it terribly difficult to find them, and once they have been found we have no way of permanently tagging them. This is something scientists are still working on for further research.
The other thing we are doing is protecting their habitat by declaring swaths of land preserves or national parks. This is often done because other plants and animals in the same area need protection, too. It’s a great side effect for the caecilians.
Habitat loss is not the only thing caecilians need to worry about. Disease is another serious threat to amphibians. One of the worst diseases effecting amphibians is chytridiomycosis. This is an infectious disease caused by a fungus and has been the cause of declines or complete extinction of over 200 amphibian species. It is know to effect over 350 species of amphibians and until 2013 we thought caecilians might be safe. Chytrid fungus gets into the skin of the amphibian which is devastating because amphibians breathe and take up water through their skin. This fungus interferes with that function. An infection is almost always fatal. Because most caecilians are fossorial we had hoped they might be unaffected by chytrid but a study published in 2013 did find the fungus present in 50% of the individuals tested from the wild. This was devastating news.
For years scientists have been working on a cure for the fungus, but very little head way has been made since what kills the fungus often kills the amphibian. Putting anything in on amphibians skin is instantly absorbed into their system, so it’s a thin line between curing and killing. Some head way has been made with an ionic liquid spread on the backs of frogs but this can only be done with captive individuals and is still not 100%. To date we have no real cure for this disease. 
So what can we do to help? If you are a hiker or explorer in areas where amphibians are common, the chytrid fungus is probably found there. To prevent spread of the fungus, disinfect your clothing and gear before you use them again at another site and do not transport amphibians of any kind from one habitat to another.  
On that note, if you are a hobbyist that likes to have amphibians as household pets, including caecilians, be sure you’re not getting your animals from illegal harvesting companies. Trapping for pet trade in another reason our amazing amphibians, including our caecilians, are disappearing. Make sure you’re patronizing a responsible person who sells only animals born in captivity.
For more on what you can do to help caecilians and other amphibians in the wild, check out my show notes where I have a few great organizations listed.
That’s it for caecilians! Thank you for joining me on this journey through caecilian behavior. I know I had an amazing trip and I think you did too. Conservation efforts for caecilians is my tenth favorite thing about this mysterious amphibian. 
 
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me in two weeks when we’ll talk about an animal thought extinct since the time of the dinosaurs until it was rediscovered alive and well in 1938! 
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: Odds and Ends

Summary: In this episode Kiersten and a guest host talk about a few things we know only a little bit about, such as caecilian origins and how they communicate.
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes: 
Caecilians: An Overview https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/caecilians
 
“Petrified Forest Brings the Funk with the World’s Oldest Fossil Caecilian.” Park Paleontology News, Vol 15, No 1, Spring 2023. Https://www.nps.gov/aticles/000/petrified-forest-brings-the-funk-with-the-world-s-oldest-fossil-caecilian.htm
Music written and performed by Katherine Camp
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the ninth thing I like about them is a bit of this and a bit of that. In this episode we’re going to talk about some of the amazing things that we only know a little bit about and my husband Georgiy will be joining me.
Hello Georgiy!
Georgiy: Hello!
Kiersten: Are you enjoying my series on caecilians?
Georgiy: Da!
Kiersten: I’m so surprised about all the amazing attributes these animals have. I think it’s my favorite research so far!
Georgiy: I’m surprised that they have lived for so long and we hardly know anything about them!
Kiersten: I agree and speaking of which. New information about their fossil history has recently been discovered!
Georgiy: Really?
Kiersten: Yes! In the Chinle Formation of the Petrified Forest National Park in Arizona, paleontologists have found the oldest caecilian fossils to date.
Georgiy: How old are they?
Kiersten: They are 220 million years old. More than 80 bones from the caecilian named Funcusvermis gilmorei have been found. Scientists are excited about this because it bumps the fossil record of caecilians back about 35 million years. So they are even older than we thought they were. These ancient caecilians have the two rows of teeth like modern day living caecilians but, unlike extant caecilians, they have legs and no tentacles. Finding these fossils answers a question that scientists have had for many years. Where are the Triassic Era caecilians? Now we know!
Georgiy: Does this tell us anything new about modern day caecilians?
Kiersten: Sort of. These fossils help support the hypothesis that living amphibians are more closely related to each other than any of their extinct ancestors. So frogs, salamanders, and caecilians that are alive today are more closely related to each other than their long dead ancestors. Even though modern day amphibians look and act so much different from each other.
Georgiy: That’s interesting.
Kiersten: I think so, too. You know what else is interesting?
Georgiy: What?
Kiersten: Caecilians are both terrestrial and aquatic.
Georgiy: I say again, What?
Kiersten: (laughs) I’ve mentioned this before in a few episodes but I wanted to make it very clear. Some caecilians live on land, terrestrial, and some live underwater, aquatic. The terrestrial species usually live under ground in tunnels, but some live in the thick leaf liter of the tropical forest floor.
Georgiy: Oh…I see. 
Kiersten: Good. Now to throw another curve at you, some species of caecilians live on land as adults but live under water as juveniles.
Georgiy: Whoa! How does that work?
Kiersten: As adults, some caecilian species lay eggs in an underground burrow near fresh water. When the eggs hatch the young make their way to the water where they slither in and spend their larval stage under the water.
Georgiy: How can they breathe?
Kiersten: Oh, good question! While in the egg the young developed external gills to help them breath under water. They also developed lungs so, when they become adults they loose the gills and emerge onto land where they breath air with their lungs. 
Georgiy: That’s just cool! So let me get this straight, some caecilians live their entire lives underground, some spend their entire lives underwater, and some split their lives between the water and the ground.
Kiersten: Exactly! 
Georgiy: This episode has been pretty cool.
Kiersten: But wait, there’s more! Another interesting thing about caecilians is how they communicate. 
Georgiy: Oooo! How do they communicate?
Kiersten: With chemical perception. 
Georgiy: Explain please.
Kiersten: Why certainly. Caecilians are the only amphibians with tentacles. These tentacles are on their face in-between their eyes and nose and detect chemical in the environment. Scientists believe that they also use these to communicate with each other. 
Georgiy: Do they talk to each other a lot?
Kiersten: Most caecilians appear to be solitary, so probably not, but we don’t know much about their social lives. The aquatic caecilian Typhlonectes natans uses chemical cues to find mates. They probably use their tentacles to sense pheromones. It’s highly possible that the terrestrial caecilians do the same thing. 
Georgiy: So they sniff out a good mate.
Kiersten: (laughs) Yes! There is something to be said about a nice cologne.
Well thanks for helping me out today, Georgiy.
Georgiy: You’re welcome.
Kiersten: That all I’ve got for this odds and ends episode. Thanks for joining me for this second to last episode about a little bit of this and a little bit of that about caecilians because it is my ninth favorite thing about them!
 
I would like to take a moment to thank a gentleman at Central Arizona College in Apache Junction, Arizona who went to great lengths to help me find information on the caecilian when I began this series. Thanks Richard, you’re the man!
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for the final thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: Defense

Summary: Join Kiersten as she talks about how caecilians defend themselves against predators.
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes: 
“Morphological Evidence for an Oral Venom System in Caecilian Amphibians,” by Pedro Luis Mailho-Fontana, Marta Maria Antoniazzi, Cesar Alenandre, Daniel Carvalho Pimenta, Juliana Mozer Sciani, Edmund D. Brodie Jr., and Carlos Jared. iScience, Volume 23. Issue 7,101234, July 2020. https://doi.org/10.1016/j.isci.2020.101234
 
“Predation on Caecilians (Caecilia orientalis) by Hawks (Leucopternis princeps) Depends on Rainfall,” by Harold F. Greeney, Rudy A. Gelis, and W. Chris Funk. Herpetological Review, 2008, 39(2), 162-164. 
 
“Skin gland concentrations adapted to different evolutionary pressures in the head and posterior regions of the caecilian Siphonops annulatus,” by Carlos Jared, Pedro Luis Mailho-Fontana, Rafael Marquez-Porto, Juliana Mozer Sciani, Daniel Carvalho Pimenta, Edmund D. Brodie Jr., and Marta Maria Antoniazzi. Scientific Reports 8, Article number: 3576 (2018).
 
“This Worm-Like Amphibian May Pack a Venomous Bite,” by Alex Fox, Smithsonian Magazine, https://www.smithsonianmag.com/smart-news/worm-amphibian-may-pack-venomous-bite-180975266/
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the eighth thing I like about these amazing amphibians is how they defend themselves.
Who are caecilians protecting themselves from? We’re aware of a few species of animals that eat caecilians. Snakes, spiders, turtles, and ants have all been reported preying on caecilians. In 2008 a surprising animal was added to this list. A group of researchers watching cameras set up to record a Barred hawk nesting site in Ecuador captured something unexpected. The parents fed their single chick many different animals including 50 individual Caecilia orientalis, a terrestrial caecilian species. Researchers are unsure how a hawk was able to find a subterranean animal easily enough to bring 50 of them to their young, but we can add these hawks to the list of caecilian predators.
So how do caecilians protect themselves from getting eaten? The first way caecilians protect themselves from predators is really a bit of a happy accident and that’s their fossorial lifestyle. Spending most of your life underground does cut down on the number of predators that can find you, although it doesn’t seem to be slowing down the Barred Hawk. Even so, evolution has given terrestrial caecilians a bit of a jump start on protecting themselves by equipping them to live underground. Aquatic caecilians spend a large amount of time close to the substrate of their chosen water source and hidden in dense plant matter, also a great place to start protecting themselves.
Caecilians do have a few other tricks up their sleeves to actively defend themselves from predators. 
But before we get to those, I want to tell you that most of the information I’ve found on this subject comes from the study of one species of caecilian, Siphonops annulatus, so it may not apply to all species of caecilians. One more I caveat need to mention is that this information is based on educated inference. Because we have not actively seen caecilians defending themselves from predators, we are making some assumptions based on the natural history of other species of animals.
Now that’s out of the way, let’s get to the really cool stuff!
Most amphibians are covered in mucus to help with oxygen transmission and disease protection, caecilians are no exception. Actually, caecilians have more mucus glands than any other amphibian. If you remember, in the locomotion episode, I mentioned that some fossorial caecilians, such as Siphonops annulatus, use their mucus to help lubricate their tunnels to make movement easier. To do this they have glands on their heads that create and release the mucus. They also have glands on their rear end and scientists assumed it was for the same reason. Not so. The gland on the rear end expels a poisonous mucus. We assume that this poison is excreted to protect them from predators that might follow them into their tunnels. 
They also tend to plug the opening of their tunnels with their rounded bums when they are sleeping or resting. A perfect way to keep a predator at bay, greet them with a face full of poison!  
Another option Siphonops annulatus has is their bite. A recent study from 2020 has shown that Siphonops annulatus may have a venomous bite! Once again this is a first for an amphibian. It’s not the first time toxins have been found in Order Amphibia. The most famous example is poison arrow dart frogs that produce poison that is excreted onto their skin. Now, they are classified as poisonous because the toxin is transferred through touch. Animals classified as venomous such as rattlesnakes and Gila monsters inject their toxin into another animal through something like fangs or teeth. Up until this recent discovery, we thought there were no venomous amphibians. 
The study found glands closely associated with this caecilian’s teeth. They found the glands in both the upper and lower jaws. These glands are the same type of glands found in certain venomous reptiles. Within the glands researchers found a combination of mucus, lipids, and proteins. The researchers isolated the cells found in the glands and discovered a similarity to oral venom glands identified in the Texas alligator lizard. As of the recording of this podcast the Texas Alligator lizard and Siphonops annulatus are not classified as venomous, but we’ll have to wait to see what future research determines.
Unlike snake venom glands there appear to be no muscles related to the glands in Siphonops annulatus to facilitate injection of poison, but the caecilian teeth are covered in mucus produced by these oral glands. This leads the scientists to believe that the venom may be secreted when the caecilian clamps it jaws down tightly on a prey item.
There needs to be more study to determine whether this substance is a toxin used to immobilize prey and if it is truly a venomous substance at all. Another purpose for this adaptation may also be as a defense against predators. Considering we’ve never seen defensive behavior in Siphonops annulatus in situ, these glands might be related to protection against predators. 
These scientists did find oral glands present in other species of terrestrial caecilians meaning that they all may have venom that they use for capturing prey and for defense. Further research needs to be done to confirm or debunk this. When they looked at some aquatic caecilians they found no oral glands, which truly intrigues researchers. 
That is all we currently know about how caecilians protect themselves from predation, but I’m sure future research will turn up even more amazing information, and I can’t wait to read about those discoveries because defense is my eighth favorite thing about caecilians. 
 
I want to take a moment to say hello to a young listener. Lydia, thanks for listening and I’m so glad you’re enjoying the podcast. Speaking of which…
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: Reproduction

Summary: Now that we know about the existence of caecilians. Let’s talk about how caecilians make more caecilians! Join Kiersten as she walks us through the various ways caecilians reproduce.
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes:
“The Care and Captive Breeding of the Caecilian Typhlonectes natans” by Richard Parkinson. Herpetological Bulletin, 2004, Number 88.
 
“Reproductive ecology of female caecilian amphibians (genus Ichthyophis): a baseline study” by Alexander Kupfer, Jarujin Nabhitabhata, Werner Himstedt. Boiological Journal of the Linnean Society, Vol 83, Issue 2, October 2004, pg 207-217.
*cool egg pictures in this paper
“Life history and reproduction of the neotropical caecilian Siphonops annulatus with special emphasis on parental care” by Carlos Jared, Pedro Luiz Mailho-Fontana, Simone G. S. Jared, Alexander Kupfer, Jacques Hubert Charles Delabie, Mark Wilkinson, and Marta Maria Antoniazzi. Acta Zoological, Vol 100, Issue 3, pg 292-302.
 
  Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the seventh thing I like about these hidden gems is how they reproduce.
When it comes to reproduction most animals will reproduce in one of three ways. If you are viviparous, you give live birth to young that have developed in your uterus. If you are ovoviviparous, you give live birth to young that have developed inside eggs that are incubated in your uterus. These young are typically born with a yolk that helps nourish the young for a few days after birth. If you are oviparous, then you lay eggs that are incubated outside the body by parental warm or substrate covering. There are animals out there that reproduce in other ways, but these are the three main ways of animal reproduction.
Caecilians use two of these reproductive techniques. Of the caecilians we know of today, they are either oviparous or viviparous. 
Let’s take a look at our oviparous species’ first. Some research has been done on species in Family Ichthyophiidae. These species lay eggs and their young go through an aquatic larval stage. The species studied in this particular research was found in Thailand and individuals were observed in the wild as well as in captivity.  It was actually one of the first times caecilians in this family had been studied in situ, which means on site in their natural habitat. Ichthyophis kohtaoensis was studied for three consecutive years and researchers discovered many previously unknown behaviors. 
When we talk about reproduction in most species, it tends to revolve around certain times of the year. Very few animals are like humans and reproduce anytime of the year. Most amphibians found in tropical areas jump into breeding mode at the start of monsoon season, so one of the first questions researchers asked is whether this would be the same for caecilians. The answer they found was a bit of yes and a bit of no. Just like other amphibians, caecilians breeding season was cyclical and revolved around the rainy season. But actual mating appeared to begin at the end of the dry season before the rains came and continued into the beginning of the rainy season. Egg laying typically happened after the rainy season had already begun.
When it comes to parental care, if there is any given, it is the female only. Ichthyophis kohtaoensis does incubate eggs for approximately three months. Toward the end of the dry season, females will begin to gain weight in anticipation of remaining in a nest to guard and incubate eggs. The average number of eggs is 37 with a range of 22-58 eggs laid in one nest. Larger females tended to have larger clutch sizes. The eggs are round and clear, so you can see the developmental stages of the young inside. The pictures they included in their  scientific paper were pretty cool!
The nest site is extremely important because the larval stage of this caecilian is spent in the water. Females will chose a site with softer substrate such as sand, loose soil beneath tree roots, and sandy clay loam under grass tufts. Every nest found was between seven to nine feet from the edge of a freshwater source. The sources were varied including standing ponds and pools, slow moving brooks and rivers, and large seasonal ponds. Once the eggs hatch the young make their way into the water and are on their own. Field studies and captive observations indicate a long larval period so the chosen body of water needs to last long enough for the young to survive through this period to adulthood.
This pattern of reproduction is only one option for oviparous species. Another pattern lengthens the parental care window and has been well studied n only one species, Siphonops annulatus. Unlike Ichthyophis kohtaoensis, the young of Siphonops annulatus do not have an aquatic larval stage. When the young of this caecilian hatch they remain in the underground nest with the mother. 
Breeding season occurs about about the same time as our previous caecilian, beginning at the end of the dry season. Females gain weight at this time and lay eggs after the rainy season has begun. This is more support for the hypothesis that caecilian reproduction is cyclical and follows the seasonal changes revolving around monsoon season because this pattern has now been seen in two species from different countries. Ichthyophis kohtaoensis is found in India and Siphonops annulatus is found in Brazil. The observations reported in the study on Siphonops annulatus were collected over a period of ten years and were gathered in situ and in captivity. 
The young of Siphonops annulatus hatch after about a month but remain in the underground nest with the mother for approximately four months. This species practices dermatophagy which means they eat skin. Specifically the young eat the outer layer of their mother’s skin. Part of the weight that the female gains before egg laying includes a thickening of the outer layer of her skin. This layer bulks up with nutritious fatty lipids that the young scrape off using special baby teeth that they lose when they leave the nest. 
In captivity, young have also been seen congregating around the mother’s cloaca, which is the orifice near the end of the tail, consuming a liquid. We don’t currently know what this substance is but it may be another nutritious liquid for the young. After four months of feeding on mom in the nest, the young will emerge into the world and be on their own. Siphonops annulatus lay fewer eggs than Ichthyophis kohtaoensis and this may be due to the intensive parental care Siphonops annulatus provides.
The last form of reproduction in caecilians is live birth and we’re going to look at one of the most well studied species of viviparous caecilians, Typhlonectes natans. Hopefully you remember from previous episodes that this species is an aquatic caecilian, living their entire lives in the water. The information about the breeding behaviors of this species comes mostly from captive specimens, so this information needs to be taken with a little grain of salt because animals always act a little different in captivity than they would in the wild. These behaviors have been in several different individuals; therefore, we feel fairly comfortable saying this is what happens in the wild. 
Once again, it appears that breeding behaviors are influenced by monsoon season, but in a slightly different way than with our egg-laying species. The dry season that comes before monsoon season is when Typhlonectes natans is triggered to begin breeding. Then the females will carry their young through the following rainy season and give birth when the next dry season begins. We have no proven information why this happens, yet, but using some inference, this pattern probably provides females with more consistent access to food while they are pregnant. They carry their young for about 10 months, so it’s important to be healthy and well fed. 
The young are born in the dry season when waters are lower and calmer. This makes it easier for them to get to the surface of the water and that is important because Typhlonectes natans must surface to breath air. The young are in danger of drowning if they can’t breath air from the surface of the water. 
While they are growing inside mom, the young scrap a secretion from the mother’s uterine wall to nourish themselves. They have small fetal teeth that help them collect these nutrients. I can’t believe there is another species of caecilian that eats its mother! 
The developing young also have gills which allows the female to pass oxygen to them in utero. When the young are born, the gills are already gone or disappear within two days. After birth the young will begin to eat small, soft invertebrates within a few days and do not rely on mom for anything. 
Females are not the only one’s involved in the reproductive process. Let’s take a quick moment, because that’s all it’s going to take, to talk about what the male contributes to the next generation of caecilians. Unlike all other amphibians, that we currently know of, caecilian reproduction is internal. Most amphibians lay eggs that are fertilized after they are laid. Caecilian males have a phallodeum which is an organ that they use to pass sperm into the female through her cloaca. No other amphibian does this. With every episode I make, these caecilians become more and more fascinating.
Whether in the water or underground, the males and females twine their bodies together aligning their cloacas up with each other. Then the male inserts his phallodeum into her cloaca and passes her his sperm. A month after mating eggs are either laid or pregnancy indicators, such as weight gain and size growth, are seen.  
All of the behaviors I talked about in this episode are based on observations of just a few species of caecilians and may not apply to other species. There is so much more we have to learn about them and hopefully we’ll be able to do that in the future.
That’s all I wrote about caecilian reproduction and I trust hope you found it as fascinating as I did because it is my seventh favorite thing about the unknown amphibian.
 
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: Diet

Summary: What do these secretive amphibians eat? Join Kiersten as she takes you on a culinary journey in this episode on caecilian diet.
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes: 
“Caecilian jaw-closing mechanics: integrating two muscle systems” by Thomas Kleinteich, Alexander Haas, and Adam P. Summers. J R Soc Interface, 2008 Dec 6: 5(29): 1491-1504. doi: 10.1098/rsif.2008.0155
 
“Diet of the Banana Caecilian Ichthyophis bannanicus in Mekong Delta, Vietnam” by Binh V. Ngo, Nghiep T. Hoang, and Chung D Ego. Journal of Herpetology, 48(4):506-513 (2014). doi.org/10.1670/13-113.
 
“Rotational feeding in caecilians: putting a spin on the evolution of cranial design” by G. John Easy and Anthony Herrel. Biology Letters (2006) 2, 485-487. doi: 10.1098/rsbl.2006.0516
 
“Dietary Partitioning in Two Co-occurring Caecilian Species (Geotrypetes seraphim and Herepele squalostoma) in Central Africa” by M. T. Kouete and D. C. Blackburn, Integr Org Bill, 2020; 2(1). doi:10.1093/iob/obz035 
 
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the sixth thing I like about these awesome amphibians is their diet.
Our understanding of what and how caecilians eat is still evolving but we know enough to know that it is fascinating!
First, let’s talk about what they eat. Caecilians are carnivores. That means they eat meat. There have been enough studies into various species of caecilians that we have a decent idea of what prey items they tend to eat. In general they focus on invertebrates that are commonly found where they live, underground, in the leaf litter of tropical forests, and underwater. Some examples include ants, termites, earthworms, snails, and some caecilians have been recorded eating crabs, lizards, frogs, and blind snakes. Aquatic caecilians eat fish and aquatic invertebrates. You probably get the drift, if it’s an insect or small animal that lives where caecilians live and it fits in their mouth, they’ll eat it.
Since caecilians have no limbs to help them catch or stabilize prey items their jaw muscles and skulls have evolved to produce a high bite force to help prevent prey items from squiggling away. Caecilians have developed a double jaw muscle mechanism that is special to these amphibians. These muscles are different from other vertebrates because they are actually located above and below the jaw as opposed to the side of the jaw. Take a moment here and place your hands on the side of your jaw. Now open and close your mouth. What you feel moving is your jaw muscles. 
If we were able to place our hands on the sides of a caecilian’s jaw, we would not feel those muscles. Scientists think that the placement of the  muscles on the top and bottom of the skull may be due to the close confines of burrows in which the caecilians live and hunt. Whatever the reason it’s one more cool adaptations these amphibians have developed.
In the last episode we talked about the two different skull formations found in caecilians. At first thought, these differences might be due to the burrowing needs of the caecilian, but upon studying bite force and diet the different skull formations may actually be related to bite force. Caecilians who have the perforated, or zygokrotaphic, skull structure utilize the leverage from the two jaw muscles more efficiently than caecilians with the completely roofed, or stegokrotaphic, skull. What exactly does this information indicate? We’re not quite sure yet. We need more research to determine what these results may mean. For now, we’ll just have to settle for the knowledge itself.
Scientists, being the inquisitive people that they are, asked if caecilians might specialize in specific diet items. Two pieces of evidence leans us towards yes as the answer. One piece of evidence supporting this is tooth shape. Caecilains that eat mostly soft-bodied invertebrates, like earthworms, tend to have sharp curved teeth. This allows the teeth to hook into soft tissue and hold tight. Caecilians that tend to eat prey items that have a harder shell, such as snails, have flatter, pedestal style teeth. This allows them to crush and grind the hard shell. 
While we’re talking about teeth, let me toss this cool fact out there. Caecilians have two rows of teeth in their top jaw and may have one to two rows in the bottom jaw! Forgive my side trip, I just couldn’t resist telling you this fascinating fact.
The second form of evidence supporting diet specialization comes from a study done with two species of caecilians that live in the same area but in different layers of soil. Researchers analyzed the diet of Geotrypetes seraphini and Herpele squalostoma two terrestrial caecilians from Central Africa. G. seraphini lives lower in the soil and eats mostly earthworms, while mole crickets which are found higher in the soil or in leaf litter above ground dominated H. squalostoma’s diet. Now, we don’t know if the diet is dependent on where they live or if they live where their preferred diet can be found. That is a study for the future.
Caecilians just can’t stop surprising us! In another study looking at feeding  behavior of caecilians scientists discovered that these amphibians utilize  rotational feeding. What exactly is rotational feeding? Think about those nature programs you’ve seen about African animals being snatched up by a crocodile. The crocodile often catches something larger than it can swallow in one gulp and spins length wise. This behavior is used to reduce the size of a prey item so it can be easily consumed.
In this study, two species of terrestrial caecilians were observed and recorded eating. They caught both species using rotational feeding to successfully maneuver large prey items into their mouths, just like crocodiles. Unexpectedly, the researchers also observed the caecilians using rotational feeding even when they caught smaller prey items that easily fit into their mouths. So the question is why do they spin when the prey item fits easily into their mouth? We don’t have a solid answer to that question yet, but the researchers postulated that because caecilians are blind maybe they are using the rotational feeding to feel the prey item to help them determine what it is. 
The last behavior we’re going to talk about concerning caecilians’ diet is the most fascinating and slightly disturbing food item I’ve come across in all my years as an animal caretaker. Boulengerula taitanus is an African caecilian that begins life by eating its mother’s skin. You heard me correctly, they eat their mother’s skin! What?! 
So, while mom incubates her eggs that she laid in her subterranean tunnel the outer layer of her skin thickens with nutritious fatty lipids. When the young hatch they have special baby teeth that help them shave off the mother’s outer skin layer. This is the only vertebrate known to use this type of parental feeding strategy! I am thankful everyday I wasn’t born bird so my mother didn’t have to puke into my mouth to feed and now I’m thankful I wasn’t born a caecilian so I didn’t have to eat my mother’s skin.
That’s all for this episode and I know you loved this episode on caecilian diets because it’s the most fascinating episode I’ve researched so far and it’s my sixth favorite thing about this amphibian.
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: Locomotion

Summary: Caecilians are legless amphibians, so how do they get around? Join Kiersten as she talks about caecilian locomotion.
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes:
“The kinematics of locomotion in caecilians: effects of substrate and body shape” by Anthony Here et. al, J Exp Cool A Ecol Genet Physiol. 2010. Https//pubmed.ncbi.nlm.nih.gov
 
“A comparative study of locomotion in the caecilian Dermophis mexicanus and Typhlonectes natans (Amphibia: Gymnophiona)” by Adam P. Summers and James C. O’Reilly, Zoological  Journal of the Linnean Society, Vol 121, Issue 1, Sept 1997, pls 65-76. Https://doi.org/10.1111/j.1096-3642.1997.tb000147.x
 
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right outside our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the fifth thing I like about these supercool amphibians is the way they get around. 
In previous episodes, we have clearly established that caecilians do not have legs, so you may have been asking yourself, how do they get around? Excellent question. Let’s get the answer.
Caecilians are definitely not the only no-legged animal on planet Earth. There are snakes, glass lizards, and fish that do not have legs. Each of these examples have a unique way of locomotion. Caecilian locomotion is something that blows my mind!     
In the last episode we learned that caecilians are divided into ten different families. Most of those families are terrestrial, which means, according to the Oxford Dictionary, of, on, or relating to the earth. Furthermore, many terrestrial caecilians, are fossorial which means they live underground. Nine of our ten families are considered terrestrial caecilians.
So how exactly do caecilians create motion? They use hydrostatic movement. Hydrostatic motion is created when one set of muscles contracts in a circular and longitudinal pattern and another set of muscles stretches in response. Think of how a jellyfish moves. That in and out, almost like breathing, motion is how hydrostatic movement works. Many species of invertebrates use hydrostatic systems to move and several species of vertebrates use hydrostatic systems in specific body parts. 
What makes caecilian hydrostatic locomotion unique is that they are the first known vertebrate to use their entire body as a hydrostatic system for locomotion. How could this get more interesting? I shall tell you! Hydrostatic movement generally depends on utilizing fluid filled portions of the body or vertebrae, but caecilians hydrostatic motion depends on a criss-cross array of tendons that surround their body cavity. Caecilians' skin and skeleton move independently of each other. Muscles do not attach the skin to the skeleton like other vertebrates. This allows them to create twice the maximum forward force of similar sized burrowing snakes that rely on longitudinal movement. 
This is one more example of what makes caecilians so unique in the animal kingdom.
Now that we know exactly how terrestrial caecilians create forward motion let’s look at another characteristic that is influenced by their fossorial lifestyle.
As you know, caecilians don’t have feet, so instead their skull bones have adapted into the perfect shape to move through the soil. They’re skulls are often described as wedge-shaped, compact, and robust. Sounds a lot like a shovel which would be perfect for digging through soil!
Fossorial caecilians’ skull bones have actually fused together in ways that other animals’ skull bones are not fused. There are two types of skull structures in caecilians. The first type is zygokrotaphic in which the skull is perforated between the squamosal, or the side of the skull and the parietal, or the top of the skull. The second type of skull is stegokrotaphic which means the skull in completely roofed. 
These two skull types are incredibly interesting to researchers and have inspired several scientific studies. One study investigated whether the amount of tunneling a species does determines which skull formation is found in their family. The thought was that the completely roofed skull formation would be  better suited to caecilians that burrow in soil more than other species that live mainly in leaf litter. To withstand the force needed to push through the soil a completely fused skull would be better, right? 
What investigators found did not support this hypothesis. There was no evidence showing caecilians with stegokrotaphic skulls had increased burrowing activity. Skull shape may be more influenced by what they eat instead, we’ll talk about this more in next week’s episode.
While investigating this hypothesis the researchers did discover that cranial shape varies greatly throughout caecilians. Even though there is variability in the position of the mouth, the temporal perforation of the skull, and the closure of the eye orbits, caecilian skulls are are generally bullet shaped which helps make burrowing much easier. 
Scientists are always asking questions and a group of researchers studying caecilian movement wanted to know if the length of a caecilian impacted the way they moved. Using x-ray video these scientists recorded the movement of five different species of caecilian that ranged in size. What they discovered was that as the length of the caecilian increased their ability to create the internal concertina motion of hydrostatic movement decreased. As the caecilians increased in length they lost the skin and skeletal independent movement because of the increase in body length. The larger species depended more on lateral movement, even though they are still capable of concertina movement. 
On an interesting note, in all species locomotion choice was dependent on substrate. When they were burrowing through soil they used a whole body or concertina motion to move forward; yet, when they were above the soil they used a lateral movement. This movement is similar to how snakes move in that side to side slithering motion.
Family Typhlonectidae contains our aquatic caecilians. There are 13 species in this family and they all live their entire lives under the water. They also burrow into soil but since the substrate is underwater it’s often more sandy or silty. Many species in this family have lost the concertina movement of terrestrial caecilians. Instead, they rely on a lateral motion to move through the water and soft substrate.
That’s it for caecilian locomotion, I hope you enjoyed this episode because it’s my fifth favorite thing about this awesome animal.
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: Species

Summary: This little known amphibian has 200 different species in its ranks. Join Kiersten as she takes you on a quick tour of the different caecilian species.
 
 For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes:
The Amphibian Class by Rebecca Stefoff
https://www.britannica.com/animal/caecilian-amphibian/classification
 
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the fourth thing I like about this unknown animal is the number of species that we know about.
I have to admit as I was doing my research into the caecilian I was amazed to discover that we actually know of about 200 species of this amphibian. Most of my friends and family looked at me with blank faces when I mentioned that I wanted to do the next series of Ten Things I Like About on caecilians. I had a few people ask me if it was going to be about people from Sicily. (laughs) Clearly not.
This episode will include a lot of scientific names so I apologize in advance but most caecilians don’t have common names since they are not very well known. 
Let’s start off with a little taxonomy, that’s the scientific classification of all living things. All caecilians are in Kingdom Animalia, as are humans, Phylum Chordata, because they are vertebrates with a skeletal system, Class Amphibia, because they are amphibians, Subclass Lissamphibia, and Order Gymnophiona also known as Apoda which is Latin for “without foot”. Within this Order there are ten Families of caecilians.
The different Families of caecilians are distinguished from each other based on physical characteristics and life history. The extant, or living species, are classified by the absence or presence of a tail, the amount of fusion of the skull bones, the degree of movement in the skull, the nature of the annular grooves (these are the cutaneous grooves that circle the body), and the structure of the phallodeum (which is the male’s sex organ). Classification is also based on whether an aquatic larval stage is present in the life history of the caecilian and whether they lay eggs or have live birth.
The youngest family of caecilians is Family Caeciliidae. The species in this family date from the Paleocene era which is 65 to 55 million years ago to today. They have no tails and most have no aquatic larval stage. There are 42 species in Family Caeciliidae. They are native to Central and South America and as adults they range in size from 4 to 60 inches.
The next seven families all date from the Cretaceous period which is 145 to 65 million years ago to today.
Family Dermophiidae includes 13 species. They have secondary annuli with annular scales. They are viviparous which means they give live birth and they are found in Africa and Central and South America.
Family Herpelidae, commonly known as the African caecilians, is native to Africa and includes 9 species of caecilian.
Family Ichthyophiidae species have tails, an aquatic larval stage and are native to Southeast Asia, peninsular India, Sri Lanka, Sumatra, Borneo, and the Philippines. There are 50 species in this family that range in size from 16 to 20 inches as adults. This family is also known as the Asiatic tailed caecilians or the fish caecilians. I couldn’t  determine why they are called fish caecilians but they do have an aquatic larval stage. 
Family Indotyphlidae is native to Africa, the Seychelles, and India. There are 21 speices in this family. Some of them are viviparous and some of them are oviparous which means they lay eggs to reproduce. The viviparous species do not have scales or secondary annuli. The characteristics that bond these species together are their non-perforated ear bone and the presence of teeth in the lower jaw.
Family Rhinatrematidae has tails and aquatic larvae. The 11 species of this family are native to South America and range in size from 10 to 13 inches as adults. This family is also known as the Neotropical tailed caecilians, the American tailed caecilians, or the beaked caecilians. 
Family Siphonopidae, also known as common caecilians, have non-perforated ear bones and no teeth in the lower jaw. The 19 species of this South American caecilian family are oviparous. 
Our last family originating in the Cretaceous period is Family Typhlonectidae. These caecilians have no tails. Adults are aquatic, so these caecilians live their entire lives in the water. The young have gills but the adults breathe through tracheal lungs. There are 13 species in this family and adults range in size from 20 to 28 inches. Family Typhlonectidae is native to South America and are also known as rubber eels. 
Our last two families are our two oldest species and originate in the Jurassic period which is 200 to 145 million years ago. 
Family Scolecomorphidae is native to Africa and only contains 6 species. They have no tail and no aquatic larval stage. Adults range in size from 16 to 18 inches. They are also known as tropical caecilians, the buried-eyed caecilians, or the African caecilians. 
Family Chikilidae is the most recently discovered family but they are one of the two oldest living caecilians. The seven species of this family have two rows of teeth on their lower jaw and are native to northeastern India. The year 2012 brought this terrestrial caecilian into the light and is named after chikila, the northeastern Indian tribal name for this amphibian. 
Now that we’ve talked a bit about the different families of caecilians let’s talk about colors! In the anatomy episode we learned that all capelins essentially look like earthworms, They have no legs, they have annuli that make their skin look segmented, and they are covered in slimy mucus. But we didn’t discuss what colors they come in. Yes! I said colors. 
Many caecilians, actually a lot of caecilians, are a gray to black color, but not all. Some caecilians are blue, some are red or orange, some have accentuated annuli that gives them a two-toned ringed appearance. Some even have bright yellow striping that runs from their head to their tails! Considering all caecilians are blind and live in mostly dark places, we’re not entirely sure why they have different colors, but boy are they pretty. 
Siphonops annulatus is a beautiful azure blue color, the sticky caecilian is dark gray with a yellow stripe down the midline of their body, the Sao Tome caecilian is bright yellow all over, the Panamanian caecilian is lime green! With 200 different species their color possibilities are quite varied.
They vary drastically in size as well. The largest caecilian is Caecilia thompsoni and this species measures in at a whopping 5 feet long! Holy Smokes! They can weigh up to 2.2 lbs. If you’d live to get a chance to see this caecilian plan a visit to Columbia, as this is their native country. 
The smallest caecilian is a tie between Idiocranium russeli from West Africa and Grandisonia brevis, from the Seychelles. These two species grow to only 4 inches. That is quite a difference in size! Boy caecilians sure as fascinating.
Well that’s it for caecilian species, try saying that five times fast, and I know you had a great time with this episode because it’s my fourth favorite thing about caecilians.  
 
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.
 

Caecilians: Anatomy

Summary: Caecilians are unique vertebrates that have some incredible anatomy. Join Kiersten as she takes on a tour of the caecilian body.
 
 For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes:
The Amphibian Class by Rebecca Stefoff
Caecilians: An Overview https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/caecilians
“An insight into the skin glands, dermal scales and secretions of the caecilian amphibian Ichthyophis beddomei.” Damodaran Arun, S. Sandy, Mohammad Abdulkader Akbarsha, Omen V. Omen, and Letha Divya. Saudi J Bill Sci, 2020 Oct:27(10): 2683-2690 doi: 10.1016/j.sjbs.2020.06.009
 
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the third thing I like about this wiggly, squiggly amphibian is their anatomy!
We’re going to start on the outside and work our way in by beginning with the skin. Most amphibian skin is slimy because it’s covered by mucus. Caecilians are no exception. They have two types of glands in their skin and one type produces mucus. The mucus covers the entire body so whenever you try to pick up a caecilian it’s slippery and that’s part of the point! Being slippery makes it much harder for predators to get a hold on you.
Another reason for the mucus is to keep the skin moist which helps with temperature regulation and cutaneous respiration. That means you can breath through your skin. 
The second type of skin gland is called a granular gland also known as a poison gland. It does appear that at least some species of caecilians produce a poison in their adult stage. While studying Siphonops annulus, a species of caecilian from Brazil, researchers noticed a concentration of enlarged mucus-producing glands on their head and their bums.
The glands on their head produce mucus to cover their skin as well as lube up their underground burrows to make it easier to move through the tunnels. The glands on their bums release a poisonous mucus that helps in predator defense. 
An extremely unusual and unique characteristic of caecilian skin is that they have scales. Amphibians don’t have scales, but these amphibians do! To make it even weirder their scales are under the top layer of their skin! We don’t know why they have these scales. It may just be an evolutionary hold over from ancestors. But we do know that not all species have scales, which only makes it a bigger mystery. Why do them have them? And what are they used for?
The skin is also segmented with annuli which are grooves that encircle the body. I haven’t found any information on why they have these annuli or what advantage they give the caecilian, but I’m sure there is a purpose for them. 
While we’re still on the outside let’s talk about limbs or legs. Caecilians have none! They are like snakes in this characteristic. Modern day caecilians have no vestigial components of legs at all, no shoulder bones or pelvic girdle indicating that they might have had legs in their evolutionary past. This is a testament to how old these animals are evolutionarily speaking because the fossils we have found from 190 million years ago have legs. We can make an educated guess that the legs became unnecessary as caecilians adapted to live their entire lives underground or underwater. As they evolved the bones that supported these limbs also disappeared.  
In the last episode we discussed senses, so if you’re listening in order you already know that caecilians do not have image processing eyes. Depending on the species the eyes will be covered in skin, bone, or absent all together. Those that still have an eye can probably determine the difference between light and dark but cannot see images. For a more in depth discussion of this, backtrack to episode two.
Since caecilians do not rely on vision to interact with their surroundings, they have developed tentacles that help them smell and feel their environment. The tentacles are located on the face in-between the eye and nostrils. They are short little protrusions that are chemoreceptors. For more on caecilian tentacles check out episode two of this series.
Okay, we’re going to head inside the body through the nares. As we’ve already discovered caecilians can breathe through their skin, but for most of them that does not provide enough oxygen to survive. Most caecilians have a functioning right lung and a vestigial left lung that doesn’t process much at all. The breathing pattern includes a long exhalation with short inhalations through buccopharangeal pumping. Let me explain that sentence. That means they breathe a long breath out and breathe in short breaths by puffing their cheeks and floor of their mouths in and out. This patten of breathing prevents mixing the clean oxygen that comes in and the carbon dioxide that goes out. This seems to unique to caecilians, at least in the amphibian family. The normal respiratory rate of Typhlonectes natans is 4 to 7 breaths per hour!
Most caecilians have at least one lung but two species of caecilians have no lungs at all. They must do all of their respiration through their skin. How coo is that!?
Let’s move on to the skeleton. The most fascinating part of the caecilians skeletal structure is…well, all of it! Since most caecilians dig into soil, whether on land or underwater, their skulls have fused many of the typical individual bones that are found in amphibian skulls so it can withstand the pressure of pushing through the dirt. The head comes to a point at the nose to make it easier to move through substrate. Small, sharp teeth line the inside of the upper and lower jaw. The mouth is on the underside of the head. Three sets of jaw muscles hold the jaw shut tight so no accidental ingestion of soil happens. This is a fascinating adaption to living underground!
Depending on species, caecilians can have 95 to 285 vertebrae that run down the entire body. Double-headed ribs attach to each vertebrae except the one directly behind the skull and the last few toward the tail. The ribs do not support the body structure like some other cylindrical vertebrates. The muscles of the caecilian actually forms a sheath around the skeleton that is attached to the skin with fibrous connective tissue. This allows the skin and muscles to move together. This cylindrical muscle sheath is what gives their body form.
Caecilians lack functional bone marrow which is where blood cells are produced in other vertebrates, so their blood is created by the liver, kidney, spleen, and thymus.  
The digestive tract consists of teeth, tongue, esophagus, stomach, intestines, and a pancreas. Caecilians are carnivores so their digestive tract is set up to digest meat.
Depending the species, the caecilian’s snake-like body ends in a short tail or none at all. The cloaca is located near the tail on the underside of the body. This is an orifice through which waste is dispelled, eggs are laid, and fertilization occurs. Not all at the same time, though.
 
That pretty much covers anatomy for caecilians. I hope you enjoyed learning about their unique physiology because it is my third favorite thing about them.  
 
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.
 

Caecilians: Senses

Summary: This amazing amphibian’s senses are unique and almost unbelievable! Join Kiersten as she sheds a little light on caecilian senses.
 
 For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes: 
The Amphibian Class by Rebecca Stefoff
“Underground amphibians evolved unique ear.” by PlanetEarth Online. https://phys,org/news/2014-07-underground-amphibians-evolved-unique-ear.html
Caecilians: An Overview https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/caecilians
“The comparative morphology and evolution of the eyes of caecilians (Amphibia, Gymnophiona) by Marvalee H. Wake, Zoomorphology: 105, 277-295 (1985) https://link.springer.com/article/10.1007/bf00312059
Music written and performed by Katherine Camp
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
This episode continues caecilians and the second thing I like about this amphibian is their senses!
 
Let’s dive right in, listeners, because this is some fascinating stuff! We’re going to start off talking about vision. In the first episode my guest co-host and I touched quickly on the fact that caecilians are essentially blind. Let’s explore this in a bit more detail. 
In all the species of caecilians that have been investigated it appears that their eyes are either covered by skin or bone. Interestingly all of the examined species have a functional photoreceptor. What does this mean in layman’s terms? It means that they don’t have eyes that help them see images but they may still use their eyes to detect light. 
Ancient fossils of caecilians showed that they had larger eyes that might have been used to see images but over the millennia their eyes have become smaller and weaker. We know why this has happened. Caecilians live in dark places, underground and underwater. This behavior probably evolved slowly as they adapted to the pressures of survival in a changing world. As they relied less and less on light their eyes became smaller.
Scientists, always on the hunt for more information, asked the question “What exactly happened to the eyes of caecilians as they evolved?” Did they retain all the components of a functional eye or did they loose certain structures that were no longer needed? In 1985 a biologist in the Department of Zoology at the University of California Berkley found some answers. At the time Marvalee Wake investigated all the caecilians that were known and studied the structure of their eyes. Seven differ trends were seen. 
1. The eyes were covered by thicker skin as well as bone.
2. Nonessential ocular muscles became smaller or nonexistent
3. The retina progressed from a typical layered pattern to fewer cells to a net like formation instead of layering
4. The optical nerve starts off present then becomes smaller and weaker then to only a small amount of cells
5. The lens of the eye is originally round or spherical then progresses to crystalline to cellular to absent.
6. The vitreous liquid in the eye is lost
7. The cornea becomes attached to the covering skin and the lens becomes attached to the cornea and retina.
All of these trends show how the eyes of caecilians became obsolete, but some structures still remained. 
Another project from 2014 studied the rods and cones in the the eyes of caecilians. Rods are the structures that are active in lower light levels while cones are active at higher light levels and can detect color. They found that the caecilians optical cells only contained rods. This is further evidence supporting the thought that their eyes my still be used to detect light but are no longer used to see actual images. 
So, now we know that caecilians no longer rely on their vision to help shape their knowledge of the world around them. Some of you may be asking if they have compensated for this lack of information in some other way? I like the way you think, listeners, because this is exactly what happened!
Let’s look at the sense of smell next. Most caecilians have nostrils through which they breath but there is no evidence that indicates their sense of smell is located within the nares. Many species have another anatomical structure that helps them smell, tentacles. 
Caecilian tentacles are located on their face in-between the eye and nostrils. They have one on each side. I know when I think of a tentacle I think of the arms of an octopus, tentacles that are long, thin, and capable of grasping objects. Caecilian tentacles are not like this and thank goodness! Could you imagine having two long squiggly arms that pick up random items sticking out of your face?  Whoa! Talk about problems! Caecilian tentacles are more like short nubs. 
The tentacles of caecilians are chemoreceptors. Essentially they help them smell. They use them to gather information about their environment such as what kind of soil they are in and where they can find food. Caecilians are carnivores so they are always on the look out for terrestrial insects and other invertebrates to eat. Terrestrial and aquatic caecilians use their tentacles in the same way.
The tentacles are attached to the tear ducts and the Jacobson’s organ also known as the vomeronasal organ. Being attached to the Jacobson’s organ is a good indication that these tentacles are used for smelling. Almost all  amphibians, reptiles, and mammals on earth have a Jacobson’s organ that helps  them detect smells. 
These facial organs have a secondary purpose as well. Caecilians also use these tentacles as tactile receptors which means they use them to feel their environment as well as smell it. This is extremely helpful when you have poor or no vision. Caecilians are the only amphibians that have tentacles. They most likely evolved to help compensate for their failing vision.
The last sense we’re going to talk about is hearing. Caecilians do not have external ear holes or pinnae. When you live underground or underwater you have no real need to hear sound waves that travel through the air. But if you could feel vibrations, this would be useful. In 2014, researchers used a CT scanner to create a 3D image of a caecilians head and found something interesting. Caecilians have a much larger ventral organ in the ear than other types of amphibians. This organ is used to sense vibrations!
To deal with their underground lifestyle, caecilians have evolved a large vibration sensing organ in their inner ear. According to the study, this is different from other underground animals such as molerats. The researchers hypothesize that because the caecilians are more sedentary than other underground dwellers and they leave their head on the ground more, since they have no legs, this may be the reason their ventral organ is larger.
That’s it for caecilian senses. I know you had fun listening to this episode because it’s my second favorite thing about caecilians.
 
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another thing I like about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.

Caecilians: What are they?

Summary: Have you ever heard of a caecilian? Join Kiersten and a guest co-host to find out what it is!
 
For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.
 
Show Notes: 
The Amphibian Class by Rebecca Stefoff
https://www.floridamuseum.ufl.edu/science/carcilians-found-in-south-florida
“The Creature Feature: 10 Fun FactsAbout Caecilians (or, This Amphibian is One in a Caecilian)” by Mary Bates, https://www.wired.com
 
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
(Piano music stops)
 
Kiersten - Welcome to Ten Things I Like About… This is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 
My name is Kiersten and I have a Master’s Degree in Animal Behavior and did my thesis on the breeding behavior of the Tri-colored bat. I was a zookeeper for many years and have worked with all sorts of animals from Aba Aba fish to tigers to ravens to domesticated dogs and so many more in between. Many of those years were spent in education programs and the most important lesson I learned was that the more information someone has about a particular animal the less they fear them. The less they fear them the more they crave information about them and before you know it you’ve become an advocate for that misunderstood animal.
 
This is the first episode of caecilians and I have a guest cohost with me to kick off this series about an unknown animal that most of you have probably never heard of. My friend and cohost of my other podcast The Feathered Desert a podcast all about backyard bird feeding in the Southwest region of the United States, Cheryl is here with me today. Thanks for joining me Cheryl!
Cheryl -  Thanks fro asking me!
Kiersten - So, Cheryl do you know what a caecilian is?
Cheryl - (laughs) No! But you’re going to tell, aren’t you?
 
Kiersten - Yes! We are certainly not talking about people from Sicily although it sounds the same. The caecilians we’re talking about are amphibians. It’s spelled c-a-e-c-i-l-i-a-n. It comes from the Latin word for “blind” and we’ll find out why they were given this name shortly.  I guess the next question we need to answer is what is an amphibian?
 
Cheryl - Oh! I know this one! An amphibian is an organism that can live both on land and in the water. We typically think of frogs, toads, and salamanders when we think of amphibians. The most distinctive characteristic is that their early years are spent underwater breathing through gills and their adult years are generally spent on land breathing air through their nose. 
 
Kiersten - Exactly! Caecilians are an amphibians that most people don’t know about. Even if you were to come across one, you might mistake it for something else. Something like an earthworm. Many caecilians have segmented skin called annuli that makes them look a lot like worms. They’re also legless. Essentially caecilians are amphibians that look like earthworms. 
 
Cheryl - How exactly would I come across one?
 
Kiersten - Well, caecilians live underground. Terrestrial ones burrow into the dirt and aquatic ones burrow into the bottom of lakes and streams. You could, possibly, encounter one while digging in your garden if you live in a humid, tropical or neotropical area in Central America, South America, Central Africa, or Southeast Asia. In 2021 they were discovered in a canal in Miami, Florida!
 
Cheryl - So pretty much all over the world.
 
Kiersten - Yes, in the right habitat they are naturally found on almost every continent, except Antarctica and Australia. Although three species have been introduced into Australia.
 
Cheryl - Three species? So there’s more than one species of caecilian?
 
Kiersten  - Yes! There’s approximately 200 species of caecilians that have been discovered around the world. Can you believe there’s that many species and virtually no one has ever heard of them?
 
Cheryl - No! Don’t forget you were going to tell about why their name comes from the Latin word for blind.
 
Kiersten - Right! Thanks for the reminder. Caecilians, for all intents and purposes, are blind. As they evolved their eyes became smaller and weaker, since they spend so much time in the dark. Scientists believe they still have optic nerves but most caecilians eyes are covered by skin and some are even covered by bone.
 
Cheryl - So not using those eyes for much, then.
 
Kiersten - Not much, no. We believe that the ones covered only by skin may use them to tell light from dark, but they certainly do not use them to determine clear images.
 
Cheryl - Now you said, as they evolved they lost their eyes. That’s got to take a lot of time. How old are these animals exactly?
Kiersten - Good catch! We have found caecilian fossils dating back 190 million years ago. That’s before the time of the dinosaurs. 
 
 Cheryl - These guys sound pretty cool! I can’t wait to learn more about them!
 
Kiersten - Me too! I’m truly enjoying my research into this animal. I’m learning so much! Thanks for joining me today, Cheryl.
 
Cheryl - You’re welcome. Thanks for asking me! This animal has peaked mu interest.
 
Kiersten - Well listeners, I hope this episode has whet your appetite for more information about caecilians because this is my first favorite thing about this amazing unknown creature. 
 
Cheryl - PLus their name is fun to say!
 
Kiersten - Absolutely!
 
If you're enjoying this podcast please recommend me to friends and family and take a moment to give me a rating on whatever platform your listening. It will help me reach more listeners and give the animals I talk about an even better chance at change. 
 
Join me next week for another episode about caecilians!
 
(Piano Music plays) 
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.