Ten Things I Like About Pangolins: Digestive Tract

Summary: The amazing digestive tract of the pangolin includes a 27 inch long tongue and a stomach with teeth! Join Kiersten as she travels through the incredible digestive tract of the pangolin.

 

For my hearing impaired listeners, a transcript of this podcast follows the show notes.

 

Show Notes:

References for this episode - The Encyclopedia of Mammals edited by Dr. David Macdonald

www.savepangolins.org

https://www.discoverwildlife.com/animal-facts/mammals/facts-about-pangolins

treepangolinresource.weebly.com/digestion

bioweb.uwlax.edu/bio203/s2012/grosshue_crai/diet

“Expression Profile of the Digestive Enzymes Manis javanica Reveals Its Adaptation to Diet Specialization” by Fuhua Zhang, Na Xu, Yishuang Yu, Shibao Wu, Shaoshan Li, and Wenhua Wang; doi:10.1021/acsomega.9b02845

Pangolin Conservation Organizations: 

Rare and Endangered Species Trust - www.restnamibia.org

Save Vietnam’s Wildlife - www.svw.vn

 

Transcript

(Piano music plays)

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

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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 episode continues pangolins. The second thing I like about pangolins is their digestive tract! I know that seems like a strange thing to like about an animal but it’s a truly amazing digestive tract. 

 

Let’s start with what they eat because that has a huge influence on how your digestive tract works. All species of pangolin eat ants and termites, but mostly. The fancy name for this is myrmecophagy. On average a pangolin can eat 140 to 200 grams of insects a day. That’s almost 1/2 a pound of insects a day. Adult pangolins can eat 70 million ants a year.

 

The digestive tract starts in the mouth, so let’s start our journey there. First they use their large, curved claws to tear open an anthill or termite mound to expose their prey. Pangolins have long tongues with a sticky, viscous saliva that helps them lick up ants and termites. Then they flick their tongue in and out of the tunnels capturing a yummy meal. Most mammals have a salivary gland that helps produce saliva, aka spit, that begins the digestive process in the mouth. Pangolins have a huge salivary gland located in their chest that creates the thick saliva and lubricates the tongue. Now, get ready for one of the reasons that the pangolin’s digestive tract is #2 on my Ten Thing I Like About list. Depending on the species a pangolin’s tongue can be 10-27 inches long! The tongue is so long in the African Giant Pangolin the the tongue actually attaches to the animal’s pelvis and they can stick half of it out of their mouth! That’s 14-16 inches of tongue!

 

Once in the mouth, digestion often begins with chewing. That’s why Mom always says chew your food! But pangolins do not have any teeth, so the ants and termites slide right down the esophagus into the stomach. 

 

Most of us have probably encountered ants at some point in our lives and some of you may know that the they are covered in an exoskeleton made of chitin. This is pretty tough stuff so you may be thinking how does the pangolin digest those little buggers if they don’t grind them with teeth. Get ready for the second reason the pangolin’s digestive tract is #2 on my Ten Thing I Like About list. They have keratinous protrusions sticking out from the lining of the stomach that help them grind up the ants they are also referred to as pyloric teeth. 

 

What? I’m imagining the Sarlacc pit monster from Star Wars in the pangolins stomach! How cool is that. It’s really more like a bird’s gizzard, which is a pouch off the side of some species of birds’ digestive tract that is muscular and helps them break down tough seeds, shells, and insects. 

 

There does appear to be a difference in Asian versus African pangolin species stomachs. Asian species have there horny protrusions and African species do not. We ‘re not sure why there is a difference, but one thing they both have in common is that they all swallow small rocks and sand that settles in the stomach and helps grind up the ants and termites.

 

Okay, why ants? There are so many other insects out there that have got to be easier to eat right? We don’t really know why pangolins ended up specializing in eating ants but it most likely developed as a way to avoid competition from other carnivores. If the pangolin is the only one eating ants they have to fight anyone to get food. Also ants are a protein rich food. They contain 50% crude protein and over 20 amino acids. That is a great source of protein for a carnivore! But you have to be able to utilize that protein. So the next question is how do pangolins do that?

 

Stomachs produce digestive enzymes. These enzymes help break down the food we eat. The diet an animal eats influences the enzymes that are found in the stomach. Recent studies have determined that the pangolin digestive tract is so specialized to eating ants and termites that they cannot successfully eat anything else and survive long term. Pangolins eat a lot of insects and those insects’ exoskeletons are made of chitin. Chitin is where the protein and amino acids are found but it had so be broken down to be properly absorbed by the body. An enzyme called chitinase does just that. 

 

Some scientists in China have delved into the make up of the Sunda pangolin’s digestive enzymes and they have found something interesting.  In both the saliva and stomach fluid chitiase was present. They also found a lack of enzymes typically found in other carnivores that help breakdown other sources of proteins. This is one of the main reasons they are not seen in captive environments such as zoos and one of the biggest hurdles rehabbers must overcome to save injured pangolins. They simply do not have the correct enzymes to break down the food and absorb the nutrients from items that are readily available to these facilities. 

 

All of these amazing facts about the pangolin digestive tract is why it is #2 on my list of Ten Things I Like about pangolins.

 

Please visit savepangolins.org to find out even more about pangolins and discover what you can do to save this unique animal. To help the African Cape Pangolin visit the Rare and Endangered Species Trust at restnamibia.org and to learn more about Asian pangolins and help the Sunda and Chinese pangolin visit Save Vietnam’s Wildlife at svw.vn. 

 

Join me next week for another ten minute podcast focusing on another thing I like about pangolins.

 

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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.