BOB HIRSHON (host):
Squirrels vs. snakes. I’m Bob Hirshon and this is Science Update.
In California, ground squirrels make up a big part of the rattlesnake’s diet. But they also have proteins in their blood that counteract their predators’ bites.
MATT HOLDING (Ohio State University):
And these proteins will bind irreversibly to the venom proteins and inhibit the venom from causing toxic effects in the squirrel.
That’s Ohio State evolutionary ecologist Matt Holding. He says the snakes may have the upper hand, however. He and his colleagues tested the performance of rattlesnake venom from 12 different California locations. They report in the Proceedings of the Royal Society B that venom was about 10% more effective when exposed to the blood of local squirrels than to that of more distant squirrels.
So this indicates that venom is locally adapted, that natural selction can actually directly fine tune the venom composition of snakes such that it can avoid these local squirrel inhibitors.
I’m Bob Hirshon, for AAAS, the science society.
Story by Susanne Bard