For humans, cannibalism is the stuff of horror movies. But in the animal kingdom, it’s more common than you might think.
All kinds of animals have been caught chowing down on members of their own species. The practice seems especially widespread in invertebrates. But amphibians, reptiles, mammals and birds have been known to make a meal out of their own kind, too.
Some female spiders and insects famously eat their male partners when they mate. Black widows sometimes devour their smaller male mates. And female praying mantises bite off their partners’ heads.
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Other animals occasionally eat their own kids. Some comb jellies snack on their young when food is scarce. And wild hamsters seem to develop a taste for their children when they lack key nutrients in their diets. On the flip side, some mamma insects and spiders allow their babies to devour them. That allows the newborns to start off life with a feast.
There are also animals that eat their peers. Some amphibians, for instance, have two larval forms. One is normal. The other is a cannibal form. The cannibal larvae have bigger mouths and sharper teeth — the better for scarfing down other larvae with. And that’s not even the most extreme form of peer-on-peer cannibalism. Some shark embryos eat their brothers and sisters while still in their mother’s womb. Only the strongest embryo survives to be born.
There are some risks to cannibalism. If an animal eats one of its own kind that died of disease, it risks getting that illness too. And if an animal gobbles up too many of its own offspring, that sort of defeats the point of reproducing. But for many animals, it’s sometimes worth living in a spider-eat-spider or shark-eat-shark world.
Want to know more? We’ve got some stories to get you started:
Attack of the inner-cannibal mega-shark History’s largest shark may have gotten mega-sized after eating its unborn siblings. (11/10/2020) Readability: 7.0
Wild hamsters raised on corn eat their young alive European hamsters raised in the lab turn into crazy cannibals when fed a diet rich in corn. The problem may trace to a shortage of a key vitamin. (3/7/2017) Readability: 7.5
What’s for dinner? Mom. One spider’s extreme motherhood ends with fatal family feast. (5/7/2015) Readability: 6.1
Humans can definitely be counted among animals that have practiced cannibalism. Join TED-Ed on this brief tour of people eating each other throughout human history.
Explore more
When prey get scarce, these jellies become cannibals
How Hannibal the cannibal led to a discovery about cobra diet
These male spiders catapult away to avoid being cannibalized after sex (from Science News)
Some animals eat their moms, and other cannibalism facts (from Science News)
Activities
What type of cannibalism do you think is most common in lions and bears? Do you think cannibalism is more or less likely in fish that lay lots of eggs? And why do you think spadefoot toads cannibalize each other? Submit your guesses on this quiz from TED-Ed! And check out their associated video for all these answers and more.
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