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Praying mantis -

In one of the more curious cannibalistic creature tendencies, the female praying mantis has been known to bite off the male’s head during mating. She then proceeds to eat his corpse for nourishment.

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Praying mantis -

This doesn't happen all the time, however. National Geographic reports that females make a meal out of the males only between 13-28% of the time. Apparently, whether or not the male is irritating her plays a role in her decision to eat him.

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Praying mantis -

And eating the males is quite beneficial to females, as a study published in 2016 found that when female Chinese mantises consumed their mates, they acquired important amino acids that were then incorporated into the eggs they laid, the number of which appeared to double after cannibalizing a male.

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Prairie dogs -

Deceivingly cute, the cannibalistic habit is most prolific in the black-tailed prairie dog communities, where up to a third of offspring can reportedly fall victim to infanticide.

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Prairie dogs -

John Hoogland, behavioral ecologist at the University of Maryland Center for Environmental Science, found in his studies that female family members of the mother would kill and eat her litter—what we might call their nieces and nephews—when the mother left the burrows to go foraging. Hoogland hypothesized that the infanticidal cannibalism left more resources for the killer's own litter.

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Sand tiger sharks -

Before they even leave the womb, when the first embryo of a sand tiger shark reaches a certain size, it starts feasting on all its younger gestating siblings and gobbles down the rest of its mother’s unfertilized eggs as well.

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Sand tiger sharks -

Some scientists think the strategy allows baby sharks to grow large and strong enough so that once born they won’t be so susceptible to other predators, and they'll have a better chance at survival. Others think that since female sand tiger sharks can mate with more than one male at a time, gestating siblings from the same father will conspire together to eat their unborn half-siblings.

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Black widow spiders -

Like praying mantises, female black widow spiders will commonly devour the much smaller males, sometimes mid-mating. This sexual cannibalism is what gave the spiders their “widow” moniker.

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Black widow spiders -

The males do sometimes try to escape their fate, but most of the time they accept it, and sometimes they even reportedly willingly participate in it—“copulatory suicide” is what it’s called when some male spiders willingly somersault into the waiting females’ mouths, and they can reportedly transfer sperm while being consumed.

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Chimpanzees -

Jane Goodall, esteemed British primatologist, recorded chimpanzees eating other chimps back in 1977. Since then, there have been many more documented examples of cannibalism among the great apes due to reasons ranging from nutrition and survival, to insurrection and tribe wars.

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Chimpanzees -

This cannibalism usually takes the form of eating newborn infants. Males will kill the young of opposing tribes and retreat to the trees to eat it. Others will steal and eat infants from the arms of their mothers in what is believed to be an effort to increase their own breeding opportunities with the females.

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Dark fishing spider -

The male dark fishing spider accepts his fate early and curls up immediately after mating to provide a little post-coitus snack for the female. It’s only a snack because the female is 90% larger than the male...

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Dark fishing spider -

A study published in Current Biology found that females who ate their male partners produced spider babies that were 20% larger and survived 50% longer than those born to non-cannibalistic mothers.

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Freshwater shrimp -

It’s not uncommon for freshwater shrimp to eat some of their young when food is scarce, but their cannibalism is kicked up a notch when they are infected by the Pleistophora mulleri parasite. The tiny parasite can live in their muscle fibers in the millions, demanding more and more food but making it harder for their host to catch traditional prey.

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Freshwater shrimp -

These hungry and handicapped shrimp then set their sights on the unsuspecting young ones of their own kind, which they can eat in startling numbers.

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Crab spiders -

Then there are the creatures that don’t eat their babies but let their babies eat them! In order to ensure the survival of her offspring, a female crab spider will offer up her own body as a meal.

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Crab spiders -

Called matriphagy, this behavior is also a strategy that ensures one's genes are successfully passed on, and is practiced mainly by insects and arachnids.

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Caecilians -

These limbless amphibians live underground and practice a chilling form of matriphagy that doesn’t require the death of the mother. Instead, the babies munch on their mother, and their mother regenerates.

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Caecilians -

The mother produces a special outer layer of skin, rich in fat and nutrients, and her babies will rip off and eat this skin with specially adapted teeth. The skin then grows back, replaced approximately every three days. This type of feeding allows the young to grow quite quickly.

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Lions -

When a male lion takes over a pride, it’s not unusual for him to kill any existing cubs, as he’s just not interested in becoming a “stepfather” and using his own resources on cubs that aren’t his own.

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Lions -

Getting rid of the cubs occasionally (but not always) involves cannibalism. The whole process is beneficial for the male not only as a source of food, but also because he can now breed with the mothers more quickly.

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Hippopotamuses -

Though hippos are primarily herbivores, there have been cases recorded of these hulking animals feasting on the carcasses of their own kind—not the babies, however.

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Hippopotamuses -

With increasing drought and habitats ruined by humans, scientists suspect this vegetarian animal’s cannibalistic behavior has been brought on by extreme need, forcing the hippo to find its nutrition in the most brutal of places.

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Dyeing poison frogs -

Dyeing poison frogs leave their new tadpoles in pools filled with older members of their own species, who have been known to take a bite out of the little ones.

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Dyeing poison frogs -

The reason why they leave the young ones to be attacked by their older relatives is because, since the old ones grew up successfully, the pool itself is assumed to be conducive to life, whereas an empty pool—though free of hungry frogs—might not have the conditions necessary for a tadpole to become a frog.

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Hamsters -

Though small and adorable, even hamsters have been known to eat their own kind. Mothers are known to sometimes eat their own newborn babies, both in captivity and the wild.

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Hamsters -

But it isn’t by choice. Scientists believe that hamsters are only cannibalistic when they are deficient in important vitamins and minerals, including the extra protein mothers need while lactating. Survival becomes more important than the success of breeding.

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Anglerfish -

It’s unclear who is consuming whom when it comes to the strange anglerfish mating ritual. Once the male anglerfish finds a female anglerfish, it bites into her belly, and then the male’s tissues begin to dissolve as he fuses with the female’s body forever.

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Anglerfish -

The male’s eyes, head, fins, and organs melt into the female’s body while the female's blood vessels begin to penetrate his body so that her nutrients enter what’s left of him so that his testicles will grow. Essentially, the male becomes a parasite in her body that produces sperm, and the anglerfish can reproduce by having both the male and female reproductive organs.

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Cane toads -

As well as mothers eating their young, siblings are also known to eat one another. Commonly seen in Australia, bigger tadpoles will feast upon their just-hatched younger siblings.

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Cane toads -

This occurs in places where cane toads are an invasive and destructively abundant species as a response to within-species competition for resources, since they have no other competitors. This phenomenon has actually spurred an evolutionary adaptation within the species as Australian tadpoles have started to mature much faster than their native South American counterparts in order to avoid becoming a snack.

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Polar bears -

Although cannibalism is not unheard of in polar bears, it was once very rare. In recent years, however, the Arctic bears have been spotted gruesomely feeding on their children. Some climatologists think the effect of climate change that is melting polar ice and impacting their normal food supply (usually seals) and hunting activities is turning them into cannibals out of necessity.

Sources: (National Geographic) (Science Times) (Discover Wildlife) (Science Focus)

See also: Chimeras, hybrids, and genetically modified animals

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