Rattlesnakes: Anatomy

Summary: Rattlesnakes are terribly misunderstood animals. Join Kiersten as she kicks of this series on rattlesnakes with anatomy

 

For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean

 

Show Notes: 

America’s Snake: The Rise and Fall of the Timber Rattlesnake by Ted Levin

Rattlesnake: Portrait of a Predator by Manny Russo

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. 

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 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 is the first episode of my second misunderstood animal, rattlesnakes. The first thing I like about this majestic reptile is their anatomy. Since rattlesnake are snakes, we’ll start off with general snake anatomy and then we’ll talk about the physical characteristics that make rattlesnakes, rattlesnakes.

Let’s start off at the head with one of the snake’s most well-known physical characteristics and the one that has people associating it with the devil. The forked tongue is for more than just scaring humans. It’s an amazing adaptation that helps snakes interpret their surroundings. The tongue flicks in and out of the mouth to gather scent information. Snakes are essentially “tasting” the air when they flick their tongue in and out. The slightly damp tongue gathers scent particles when it is exposed to the air. When it comes back into the mouth the ends settle into the Jacobson’s organ that is situated in the roof of the snake’s mouth. This structure processes the scent particles that the tongue gathered telling the snake what’s in the environment around it. 

It’s quite amazing and allows the snake to find prey items, water, shelter, and protect itself against predators, all with the flick of its tongue. 

Moving to the top of the head, we find the eyes. This is another characteristic that freaks people out because snakes never close their eyes and some people think that they are being constantly started at with evil intent. But that’s not true, at all. Snakes don’t close their eyes because they can’t. They have no eyelids. They do have thicker lens’ over their eyes that help protect them from the environment like other animals’ eyelids. Snakes don’t have great distance vision either. So they are certainly not staring at you from several feet away. Their vision helps them pinpoint their strike when their prey or a predator is at very close range. 

At the end of their cute little snouts are their nares. Since they are terrestrial vertebrates, they do breath air. That’s what they use their nostrils for, since most of their olfaction is done with their tongues, but they do have olfactory epithelial cells that line the nasal passages. The presence of a predator or prey triggers a tongue flick, so some scent is likely absorbed through the nasal passages. 

Just below the nostrils, in between the eyes and the nostrils, are the thermal pits. As far as we know, most snakes have thermal pits, but they range in their sensitivity depending on species. These help snakes detect temperature differences in their environment. It’s another adaptation for hunting prey and keeping themselves safe. As they grow, snakes learn the differences between prey items, predators, and environmental heat signatures that might lead them to safe shelter.

When we enter the mouth, we’ll see teeth. All species of snake, as far as we currently know, have teeth. They will vary in size, placement, and number, but all snakes have teeth. When you don’t have hands or paws to help you capture or hold your food, teeth come in super handy. (See what I did there?) Hee-hee! Snake teeth do have one thing in common across species and that’s the curvature of the teeth. Snake teeth are recurved which means they curve backwards. What we mean here is that their teeth are curved towards the back of the mouth. One more indicator that their teeth are used to hold food before they swallow it whole.

Speaking of swallowing, that leads us to our next super cool snake adaptation. I’m sure many of you have heard that snakes can unhinge their jaws to swallow something ten times bigger than their own mouths. This is another rumor that often sets people against snakes and it’s false. They cannot unhinge their jaws. They can expand their jaws with the help of ligaments attached to the upper and lower jaw bones. This allows them to swallow food approximately three times the size of their heads. 

Once we get past the mouth, snake anatomy is very similar to our own anatomy. They have an esophagus that transports their food to their stomach where it’s processed and passes to the small intestine through the large intestine  to the rectum and out the cloaca. They have a trachea, looks like a hole inside the mouth, leads to their lung. They can close off their trachea when eating or drinking and are able to move it around a large food item so they can breath while they eat. I’ve seen snakes I’ve worked with at zoos do this and it looks kind of like a straw sitting next to the rat they are consuming. It’ both cool and weird.

Most snakes have only one working lung, this is also true of rattlesnakes. Their right lung is the functioning lung. Overall the respiratory system of the rattlesnake, and most other snakes, is not exceptionally efficient at providing oxygen to the body. They are not into exertion, they simply don't have the lung capacity to sustain a high level of prolonged activity.

Snakes also have a brain, a heart, a liver, two kidneys, a pancreas, a gall bladder; sound familiar? Males will have testes and a hemipenes used for reproduction and females have ovaries, an oviduct, and a uterus.

This is a very basic rundown of snake anatomy. We’ll be going in depth with a few of these topics as this series progresses. For now, let’s look at three anatomical characteristics that make rattlesnakes unique among other species of snake. Fangs, venom, and the rattle.

Fangs are teeth that give the rattlesnake that menacing face, but they only use the fangs when they are striking, most often for catching prey. The fangs can be in the front of the mouth or in the back. Most rattlesnakes have front fangs that come down from the top jaw. In any snake, fangs are found only in the top jaw. Fangs are modified teeth that allow for injection of venom. They are like other enamel covered teeth but with a hole either at the base or down the middle of the tooth that allows for venom injection. In most rattlesnakes, the fangs can be folded into a pouch of skin on the roof of the mouth when they are not needed. They can be pretty long and can get in the way when swallowing food. 

Venom is what makes people fear rattlesnakes most. But this substance was mainly developed for catching prey and pre-digestion of food. According to current research, scientists believe venom was not developed as a defensive mechanism against predators. Venom generally comes in two forms: one is a hemotoxin which will eat away at the walls of capillaries and other circulatory vessels causing blood to pool in body cavities; the second is a neurotoxin which taxes the nervous system shutting down nerve impulse transmission leading to paralysis. Now these both sound pretty bad, and if you're a mouse it’s not looking good for you, but as a human or a large mammal you’re most likely just fine. Venom is produced from glands in the upper jaw of the snake’s head. I’ll dive deeper into venom in its own episode.

Last but not least, the rattle. This physical characteristic is found only on rattlesnakes and no one else. The rattle is made of keratin, the same thing that make up our hair and nails, and grows each time the snake sheds. It is essentially made from the last terminal scale of the rattlesnake’s tail. It remains behind after each shed to create another link in the snake’s rattle. The rattle is hollow and flexible. When it is vibrated back and forth a sound is produced. Research tells us that this physical characteristic is used for defensive purposes, alerting predators or other unsuspecting creatures that a rattlesnake is nearby and wishes to be left alone. The rattle is so fascinating, I’m going to dedicate an entire episode to the rattle in a few weeks.

Thank you for joining me for my first episode of rattlesnakes. This is going to be an exciting series and I can’t wait to share it all with you. I’m glad I started with anatomy because it’s my first favorite thing about this misunderstood 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 episode about rattlesnakes.

  

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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.