Bats: Microchiroptera

Summary: Now that we've talked about Megachiroptera, let's talk about Microchiroptera! Join Kiersten as she talks about the smallest bats.

 

For my hearing impaired followers, a transcript follows the show notes on Podbean.

 

Show Notes:

“Bats in Question: A Smithsonian Answer Book,” by Don E. Wilson

Music written and performed by Katherine Camp

 

Transcript

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Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.

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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. 

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.

The third thing I like about bats is Microchiroptera. To be honest I like everything about bats, but I have set a precedent and must follow the pattern of previous series, so third thing it is!

Last episode we talked about the larger bats called Megachiroptera that are found only in the Old World of Asia, Africa, Australia, and some Pacific Islands, so this episode we will talk about the Microchiroptera or smaller bats. These bats are not confined to a specific region in the world. They are found on every continent on the globe except Antarctica, and let’s face it, there is not a lot that wants to leave there full time. 

As a quick refresher, bats are all classified under Class Mammalia, Order Chiroptera, Mega and Micro are separated into suborders, so they are related in the fact that they are all bats, but there are enough differences in physical anatomy, behaviors, and genetics to be separated at a suborder level. Megachiroptera have only one Family Pterpodidae, but Microchiroptera has many families. Currently the classification of bats is still undergoing a bit of a shake up, as all classification is continually evolving, but we recognize 17 families of Microchiroptera with over 900 different species. 

As an example of the ever changing classification system, before I began my graduate work with the Tricolored Bat, it was classified as a pipistrelle with the scientific name of Pipistrellus subflavus, but when I was writing my thesis the scientific name had been changed to Perimyotis subflavus. Their genus had been changed based on research at the time. I have to admit I was a bit disappointed because it’s just more fun to say pipistrelles than perimyotis, but whatcha gonna do?

Okay, I’m going to follow the same pattern I did with the Megachiroptera episode, so these two suborders will be easy for you to compare should you wish to do so. 

Where are Microchiroptera found? They are found on every continent in the world which means they are found in the New and Old world. So those of us that live in the Americas get to pleasure of living with these little darlings. Now, this does not mean that all families of Microchiroptera are found on every continent. There are three families that are shared by both hemispheres Emballonuridae, Molossidae, and Vepertilionidae, but different species of these families will be found on different continents.

What kind of habitats are Microchiroptera found in? They can be found in almost any type of habitat. They are most common in forested area and deserts areas around the world, but some species can be found in grasslands and savannas. They can be found at sea-level and at elevations of 5000 meters above sea-level. They will be found in areas of high rainfall, and areas with scare rainfall. Microchiroptera are extremely diverse mammals. 

What do our smaller bats eat? The majority of micro bats are insectivorous, which means they eat insects. There are many ways that they catch insects but most of them catch insects on the wing. This is where echolocation comes in. If you are hunting something that is constantly moving and you are also constantly moving, how to you find what you’re looking for? Echolocation. Bats create sound with their larynx, much like the rest of mammals do, including humans, that they send out through their mouth. When they are hunting or navigating during flight they use a high-frequency, ultrasonic sound that once emitted bounces off of whatever it hits and comes back to the bat. The bats can decipher the frequency and time that these sound waves bounce back to them and they know if it is an insect they want to eat, another bat flying into their path, a stationary tree they must avoid, or anything else in their environment. These decisions are made in seconds! I mean, holy cow!

There are other methods of hunting insects, as well, but echolocation is still used. Some bats are called gleaners which mean they hunt for insects that are more stationary and may even be terrestrial, such as scorpions. These bats are listening for insects that are on low beaches of shrubs or rocks and many of these species are desert or grassland residents. The Pallid Bat that is found in the Southwestern regions of the US is a good example and one of their favorite foods is scorpions.

What else do Microchiroptera eat? We have a wide variety of food for these bats. Some are nectar eaters and hover like nighttime hummingbirds fishing nectar and pollen out of night blooming plants such as Saguaro Cactus and agave plants. Those of you out there that love tequila can thank these guys for your alcoholic beverages. Bats are then that pollinate the agave used to make tequila. Micro bats also eat other mammals. The False Vampire bat hunts small rodents. Some Microchiroptera specialize in amphibians, hunting frogs using their breeding calls. There are also fishing bats. They swoop down and skim the water dragging their large hooked claws just below the surface catching fish that are eating insect larvae. Three species of bats found in South America do eat blood. These are the true vampire bats, two specialize in avian blood, while one focuses on mammalian blood. Some bats eat other bats. As you can see Microchiroptera eat almost everything that the planet has to offer. This is one of my most favorite things about these animals. 

How do Microchiroptera and Megachiroptera differ? All bats have the same basic anatomy. So they all have a head, body, feet, and wings. They have the taut skin that is stretched across the wing bones called the patagium. The one bone in the wing that our smaller bats do not have is the thumb-like hook that protrudes far out on the Megachiroptera wings. Microchiroptera have a small nail that does grows on that small bone, but it does not stick out as far as the Megachiroptera. 

Another difference is in the patagium found between the legs of the smaller bats. Family Pteropodidae, our Mega bats, do not typically have a patagium between the legs, where are most micro bats will have some sort of patagium there. They can differ in style. Some will have a long tail that sticks out past the patagium, while others will have tails that end at the same length as the patagium. This skin can be used for quick changes in flight, that’s helpful when you’re chasing a small flying insect that can switch direction on a dime, and can be used as a scoop to grab an insect like a net and toss it to your mouth. I mean, how useful is that!

What time are Microchiroptera active? As far as we know, all micro bats are nocturnal. We are still discovering new species and animals are constantly evolving new behaviors to best survive in an ever changing world, but current knowledge stats that microbats are nocturnal. They are only out and about at night. Depending on species, that can be just before dusk and last only half an our, or come out after midnight and hunt until dawn. 

They can be found in large colonies such as Brazilian Free-tailed bats that will roost in groups that can number in the millions, or they may roost with a few other individuals such as tent-making bats in South America, or as solitary loners like the Red bats of North America. Each species has evolved this behavior to optimize their chances at survival. Males and females may not always be found together either. Unlike Flying Foxes that tend to stay together though the year, micro bat sexes may live separate lives during different portions of the year. For example the Tri-colored Bat that I studied, roost together in their hibernaculum in the winter, makes it easier to breed, we’ll talk more about that in our Reproduction episode, but they separate in the warmer months of the years with the females roosting together in nursery colonies while the males roost with each other elsewhere.

The smallest microchiroptera, and possibly the smallest mammal on earth, is the Bumblebee Bat, also known as Kitti’s Hog-nosed bat. This little guy weighs in a just 2 grams and 29-33 mm in length. That’s similar in size to a large bumblebee, hence their common name. They are found in western Thailand and southeast Burma. They are cave dwellers and can be found in colonies numbering 100 individuals. We believe that Bumblebees Bats are gleaners, based on the contents found in their stomach which consists of spiders and other insects. Their wings are also shaped to produce a hovering motion.

One of the largest Microchiroptera is the Ghost Bat of Australia. They have a head and body length of 10 - 13 cm and a forearm length of 10 -11cm. They weigh in at 130g to 170g which is about 65 Bumblebee bats. The Ghost Bat is a carnivorous bat that hunts large insects, frogs, birds, lizards, and small mammals. They generally roost in caves, old mines, or deep cracks in rocks. They are found all over Australia but mainly in the northern regions.

Once again, I could go on and on about these amazing animals, but I will end this episode here. This has been a pretty decent summary of my third favorite thing about bats, Microchiroptera. 

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 exciting episode about bats.  

    

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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.