Gross Eating Habits Among Our Animal Friends (Little Green Notebook)

Cast your vote for the winner in the comments.

This cozy spot between the Thanksgiving feeding frenzy and our plunge into egg nog and fruitcakes seems like an excellent time to talk about disgusting eating habits. I’m not talking about our own, of course. That would be rude. Equally rude would be imposing our own mores and values regarding dining etiquette onto others in the animal kingdom, but I’m going to do it anyway.

In fact, let’s have a contest. I’ll present to you four animals and ask for your vote on the one that grosses you out the most. Let’s begin.

Our first candidate is the vampire bat, found in Central and South America. Vampire bats are wee critters, the size of a thumb. As their name suggests, vampire bats are sanguivores, feeding on the blood of other animals. How odd that out of the 1,400 plus species of bats in the world, only three evolved to live on blood and blood alone. In fact, vampire bats are the only obligate blood-feeding vertebrates.

Vampire bats are equipped with remarkable adaptations to enable them to eat. These include a special anticoagulant in their saliva to keep blood flowing as they eat, sensory organs on their noses that enable them to detect the warmth of their feast in an animal from 20 cm away, and specialized teeth which lack enamel, all the better to rip the flesh away from their food source.

These little blood suckers eat daily, up to five teaspoons of blood at a time. Their preferred prey is the cow, but a particularly hungry vampire bat might flick the cheek of a well-fed peer and dine on regurgitated blood.

Candidate number two is the worm-like caecilian. Caecilians (Gymnophiona, or naked snake) are one of three orders of amphibians, the others being frogs (Anura) and salamanders (Caudata). Caecilians live in tropical and subtropical areas, and are secretive and shy, digging into burrows with their bone-fused heads, seeking optimal conditions with specialized chemosensitive tentacles. You’re safe to picture them as large, slimy beings somewhere between a snake and a worm.

They are odd. For one thing, they produce a milk-like substance which their wriggling babies enjoy, producing high pitched clicking sounds as they approach their lactating mother. There’s more.

About 75% of these critters give birth to live young, who emerge healthy and well fed having feasted on the inside of their mothers’ oviducts with their special scraping teeth to get this job done. This maternal dermatophagy (mama-skin eating) benefits the offsprings’ microbiomes with beneficial bacteria and fungi.

There are over 200 species of caecilians classified into nine families, including Grandisoniidae. I long to know the story behind that name, but other animals call.

Photo by Peter Southwood, inaturalist photos, creative commons

Consider the hagfish, that eel-esque creature with the round mouth, skull but no vertebrae, rudimentary eye spots, and sliming capabilities par excellence. When captured, the hagfish can excrete a mucousy, viscous slime that expands up to 10,000 times its original size in less than half a second. They then twist their bodies into overhand knots and wriggle away, sliming and knotting and wriggling their way to freedom. But we were talking about gross eating habits, not gross defensive mechanisms.

Hagfish are brutal. While they have a slow metabolism and can go for months between feedings, when they do eat, it’s a scene. Preferring to devour their prey from the inside out, they are particularly fond of feasting on dead or dying sea creatures including whales, sharks, birds, and cephalopods. They use their knot-tying abilities to wrap around and eviscerate their animal meals, then burrow into the bodies, chomping away. Also, they can also absorb nutrients directly through their skin.

Moving on to something closer to home, let’s consider the house fly, that omnipresent filth fly found on decaying matter, feces, and human food. As kids we used to squeal, when a fly landed on our peanut butter and jelly sandwiches, “Gross! Flies taste with their feet! They vomit on their food!” but we shooed them away and ate our sandwiches anyway.

We were, in fact, correct. Flies have taste receptors on their lower legs and feet and will wander about on poop and popcorn alike considering their pallet. Once they’ve decided they like what they taste, they vomit up digestive juices onto their meal, breaking down the food into bits and mush which the fly can then drink with its proboscis.

This liquid diet leads to quick digestion, and flies are prone to defecating while they are eating.

Additionally, these little synanthropes (creatures evolved to live near and amongst humans, benefitting from our environmental modifications) carry up to 65 different pathogens, including those that cause typhoid fever, dysentery, cholera, tuberculosis, and leprosy.

Well, what do you think? Who among these four, with apologies to vultures and dung beetles for getting no mention, gets your vote for grossest eater? Cast your vote in the comments, or at Little Green Notebook on Facebook.

Bon Appetit!