Weird Science finds that murderous necrophiliac frogs make great dads

Aurich Lawson

If you're going to kill your partner, you don't want to waste all the energy you put into courtship. Say you're a frog. It's that time of year. You and a half-dozen other males have found some lucky female sitting in a pond. After a long, exhausting fight, you've finally found yourself ready to mate with the female. Just one problem: during the scuffle that got you there, she drowns. Oops. Now all that energy has gone to waste, right?

Not necessarily! As the authors of a study of an Amazonian frog species note, "Such occurrences are obviously detrimental to females, and may also cause a decrease in the reproductive success of males through depletion of energy without obtaining access to a live female." Fortunately, it's just these sorts of detrimental occurrences that evolution is extremely good at handling. In this case, the male frogs are able to give a dead female such a robust squeeze that it forces some of her eggs out, allowing a "successful" necrophilial mating. "This behavior can minimize losses to both partners," the authors helpfully note.

For the frogs, the eyes have it. We all know how the eye works: picks up light, converts it to nerve impulses, sends it down the optic nerve to the brain, where special areas dedicated to processing it. So, what happens if you have an extra eye? It's actually relatively easy to arrange in frogs, where the primordial eye can be removed from one embryo and transplanted to another. Pretty much anywhere you put it, it will go on to form a normal looking eye (excepting that it may be on the animal's backside, of course). But, in their unusual location, they don't have a chance to form normal connections to the brain.