Speaking of Ancient Mysteries

By | May 18, 2006

So what really killed off the dinosaurs? How about poisonous mammals?

Small prehistoric mammals may have looked like easy pickings for their fearsome contemporaries, but a new study suggests many matched might with venom.

The theory could explain how the fox-sized mammals of the Mesozoic Era 225 to 65 million years ago defended themselves against much larger predators. It also may explain why male platypuses have a fang-like venomous spur on their inside hind legs.

But wait a second, why would later mammals have lost this venom-dispensing capability? It seems to me that it would have come in quite handy for a long time.

The answer:

“The echidnas and platypus are relicts of very old stem mammals,” said lead author Jørn Hurum, a paleontologist at the University of Oslo, Norway. “All other mammals this primitive are extinct.”

The common ancestors of most modern mammals, he explained, “lost the trait when they acquired upright stance on the hind limbs. The more primitive mammals still had the legs more or less sprawling out from the body… . It is a really bad idea to have venomous spurs pointing inwards when your ankles almost meet during walking.”

See, it’s always something. Either you’ve got giant lizards stomping around trying to eat you, or you’re sticking yourself in the leg with your own venomous spur. Sheesh.