geekosystem

We love photos from space as much as the next guy, but there are some pictures we probably never need to see. Like when one of NASA's Mars rovers leaves a distinctly phallic line of tracks in the dirt, inscribing what looks for all the world like the sort of crude drawing of a penis you can see on men's room walls the world over on the face of another planet. 

The sea slug chromodoris reticulata might not have a catchy name, but it can do a neat trick never before seen in the animal world. After mating, the hermaphroditic sea slug, which has both male and female sex organs, loses its penis. Don't fret for it though, as the slug can regrow a new one within 24 hours.