Honey, I Ate the Kids

T. sarasinorum males will eat their own eggs if they are not sure who the father is. (Image credit: S. Gray via the American Naturalist)

Like any good species practicing Darwinism, a fish wants his own kin to survive.

A new study reveals male fish of one species will eat their own offspring if they're not sure about their paternity.

Here is how it arises. If lots of males are present during spawning, a male is more likely to eat the eggs he himself fertilized, the researchers found. He'll also eat them if he has a reasonable suspicion that his favored female has been, um, fishing around.

Scientists had theorized fish might do this, but it's never been documented.

The research is reported in the February issue of the American Naturalist by Suzanne Gray and Lawrence Dill of Simon Fraser University and Jeffrey McKinnon at the University of Wisconsin, Whitewater.

"The most drastic decision a father can make is to cannibalize his own offspring," the scientists write. "These results support and extend previous findings suggesting that confidence of paternity is a key factor in determining a male's behavior toward his offspring, including whether or not to eat them."

It's not clear how widespread the practice is, however. The study was done on Telmatherina sarasinorum, a small fish found in Lake Matano in Indonesia. The female fish, by the way, always know they're the moms and do not cannibalize.

Other Cannibals:

Bees, Neanderthals, Mormon Crickets