Asklemmy

Some examples in no particular order:

• Cowbirds lay eggs in other birds' nests, and if the other bird kicks their eggs out, the cowbird will come back and destroy the nest.

• You've probably heard of female black widows eating the male after mating, but did you know that this is so common among spiders that the males of some species are literally hardwired to automatically die during or after mating? Makes the whole process easier and prevents the male from getting away.

• Toxoplasmosis mind controls mice and makes them seek out cats so they get eaten and the parasite can move on to the cat.

• The hyena birth canal. If you think human childbirth is excruciating... you'd be right actually, we're pretty high up there on the list of animals with the worst birthing experiences, but hyenas have it even worse.

• There's a parasite that goes into a fish's mouth, eats its tongue, and attaches itself to where the tongue used to be and essentially becomes the fish's tongue.

• Hamsters eat some of their own offspring if they have too many to ensure they have enough resources to properly care for the rest.

• Baby sharks try to kill and eat each other in the mother's uterus.