Long-Suffering Snail Dads Carry Illegitimate Babies

If you can't find the snail in the photo above, it's because he's loaded down with thousands of cannibalistic babies—and most of them aren't even his. Dads in this marine species do all the egg-sitting, while moms scoot off to mate with other males. The males' willingness to care for the eggs of their rivals isn't just unusual: it's opposite to the standard rules of evolution.