Echidna: Diet and Digestion

Ten Things I Like About... Podcast

Summary: We all gotta eat, right? The echidna eats insects. Take a trip with Kiersten as she travels through the digestive track of the echidna.

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

Show Notes:

Short-beaked Echidna (Tachyglossus aculeates) Fact Sheet: Diet and Feeding, San Diego Wildlife Alliance Library. https://iecl.libguides.com

“Characterizing the Gut Microbiomes in Wild and Captive Short-Beaked Echidnas Reveals Diet-Associated Changes,” by Tahlia Perry, Ella West, Raphael Eisenhower, Alan Stenhouse, Isabella Wilson, Belinda Laming, Peggy Rismiller, Michelle Shaw, and Frank Grützner

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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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 echidnas and the third thing I like about this amazing monotreme is what they eat and how they digest it. I know that sound like a strange thing to like, but it’s really quite interesting.

One of the ways to tell if you have an echidna nearby is the distinctive way they hunt for food. The prey that echidnas are after lives mainly underground, so they poke holes in the soil with their long snouts. The holes are called ‘nose pokes”. Nose pokes are the width of the echidnas snout and the depth can tell you the species of echidna that’s digging around in your backyard. The depth, of course, depends on the length of the echidna’s snout. Long-beaked echidnas will produce deeper nose pokes than short-beaked echidnas. Once they find what they’er looking for, they use their long claws to tear open the invertebrates nests.

How they find their prey is not well understood. Do they use a sense of smell? Do they use vibration detection? Do they use the sense of touch? We’re not entirely sure, but it may be a combination of all three.

So, what are these echidnas digging around for underground. They are classified as myrmecophages. If you can remember way back to our first series about pangolins, you know that myrmecophages eat mainly ants. And that is one of the main prey items of the echidna. They specialize in eating termites, ants, scarab beetle larvae also known as pasture grubs, and moth larvae also known as grass grubs. When they come across beetle larva during the nose poke stage, scientists have noticed them using a corkscrew like motion to extract the larvae.

They actually prefer the social living invertebrates such as termites and ants because they offer more reward for their effort. Which I can totally understand! Of those two insects, termites are higher on the list because they have softer bodies than ants and they tend to live in larger colonies. When possible, echidnas avoid ants, termites, and other insects that bite, sting, or have other chemical defenses. Sometime they have no choice but to go after ants, so they focus their efforts on the more defenseless areas of the ant colony such as the queen, the larvae, and the pupae.

The general rule of thumb is to avoid prey that bites back, but after hibernation and before raising young, echidnas may endure some abuse to build up their fats stores.

They have also been seen foraging around trees. Here they’ll stick their snouts under loose bark looking for termites and insect larvae. If it is a rotted tree or log, they will use their powerful claws to tear open the trunk exposing the insects within.

They are not reliant on water to drink so they can live in areas without easy access to water sources.

So now we know what they eat, let’s find out how they eat. It all starts with a long sticky tongue. The short-beaked echidna can extend its tongue seven inches or 18 cm out of its mouth. They can do that more than 100 times a minute! Their genus name, Tachyglossus, actually means fast tongue. A combination of circular and longitudinal muscles allows the tongue to extend and contract. The tip of the tongue is very flexible. It’s so flexible it can curve into a U-shape. That’s probably pretty helpful for scooping up lots of yummy termites. They do posses taste buds which are located at the back of the tongue.

They must eat small ants and termites limited to only 55mm because that’s the only thing that will fit in their mouths. Their mouth doesn’t open very wide. If you ever hear someone say an echidna bit them, we know that’s a tall tail! Now, of course, they mainly focus on prey items that are already that size of smaller, but they can tear apart things that might be a bit bigger but is something worth consuming. They can hold the item down with their claws and tear it apart with their tongue.

Like many other animals who have an ant based diet, echidnas have no teeth. The do have a hard palate on the roof of their mouth that they use in conjunction with their tongue to grind their food. There are keratin spines at the base of the tongue that smoosh the food up against the hard palate grinding the insects into a paste. Mmmm. Nothing like a little insect paste to hit the spot.

Echidnas digestion is very slow. Their stomach is a single chambered organ that is elastic. It can hold a lot of insects, but it has very low levels of acid, so their stomach is not like many other species of animals, including humans, that rely on acid to digest the food they injest. Echidnas stomachs act more like a cow’s rumen which is a chamber that holds food and digests it with the help of bacteria. Digestion in these monotremes is not well understood but scientists have determined that plant matter may have a bigger role in echidna digestion than previously thought.

Echidnas held in captivity such as zoos and rehabilitation facilities tend to have quite a few gastric problems. Researchers are now collecting scat, that’s poo, from wild echidnas and captive echidnas to determine what a healthy microbiome looks like for an echidna. The more we know about what keeps their stomachs functioning properly in the wild, the better we can make their diets in captivity.

Thanks for following the digestive track of the echidna with me because it’s make 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 episode about echidnas.

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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.