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.
Rather than laying their eggs on, say, a rock, female Solenosteira macrospira snails glue egg-stuffed capsules to their male partners after mating. The male waits patiently for what may be several hours while the female produces and attaches the packets, which each hold about 250 eggs. By the end of the mating season, each male will have partnered with a handful of females (both literally and figuratively) and will be totally covered in eggs.
It takes about a month for each "clutch," or batch ...
