Why do baby sharks eat each other

5 animal cannibals

In addition to the hapless siblings, there are also unfertilized eggs as food for the young sharks. The protein-rich diet pays off: With a length of up to one meter and a birth weight of around 20 kilograms, it is very unlikely that the newborn sharks will end up as a meal themselves.


The croissants are probably the cutest child-killing, cannibalistic serial killers you've ever seen. In fact, this description does not apply to all prairie dogs. Thanks to the tireless research of John Hoogland, a behavioral ecologist at the University of Maryland, we know that some members of the genus are by no means squeamish.

After a lot of detective work, he finally found out that black-tailed prairie dogs practice cannibalism. "We noticed that almost all females mated, but very few had young to suckle them," said Hoogland, who began researching the animals in 1974.

His team also noticed that females went into their closest relatives' burrows and "when they came out, they often had some blood on their faces".

The mothers in the burrows then stopped all maternal behavior. After much effort, "we found beheaded babies down there, most of which had been cannibalized," said Hoogland.

"Then we had clear evidence."

The Utah Prairie Dog also eats its young. In other species, however, the behavior seems to be hardly or not at all widespread.

“My hypothesis is that the competition is so extreme that natural selection sometimes drives the prairie dogs to kill the offspring of their close relatives because that increases the chances of their own young surviving,” explains Hoogland.


The tadpoles of the cane toad, which is native to South America, target the eggs of their conspecifics, which they fish out of the water. They are particularly impressed by the toxins from the group of bufadienolides, which actually serve to protect the eggs.

The nutritious caviar supports their development and reduces future competition, as a study by the University of Sydney and James Cook University in 2011 shows.