May 24, 2016 I Paul Seaburn

Rattlesnakes Adjust Venom For Different Types of Squirrels

Did you know that some squirrels have evolved to develop anti-venom proteins that protect them from rattlesnake bites? Did you know that some rattlesnakes have evolved specific venom chemistries depending on which squirrels are predominant in their area? Which are you more afraid of now – rattlesnakes or squirrels?

Evolutionary biologists at Ohio State University conducted a study of rattlesnakes and squirrels in Northern California in an attempt to figure out how squirrels there manage to survive rattlesnake bites. According to their report in Proceedings of the Royal Society B, they were surprised to also learn how rattlesnakes custom-blend their venoms like master brewers.

northern pacific rattlesnake 570x380
Northern Pacific rattlesnake

You could drive 20, 30 miles down the road and find a lot of variation in the venom and our research suggests that this variation is adapted to overcoming differences in squirrel venom resistance.

Study author and environmental ecologist Matthew Holding saw this variation when his team collected venom from northern Pacific rattlesnakes (Crotalus oreganus) and blood samples from California ground squirrels (Otospermophilus beecheyi) living in 12 different areas of northern California.

MAtt Holder 570x379
Matthew Holder and a captured rattlesnake

Then they played the favorite game of environmental ecologists: Venom versus Blood. The researchers mixed the samples from both the same and distant locations. After thirty minutes, they checked to see which had won.

While the rattlesnake venom was the overall winner, the samples showed that the rattlesnakes would have done best against squirrels in their immediate neighborhood and their success rate dropped quickly against squirrels from just a little farther away.

eastern grey squirrel 570x402
Eastern Grey Squirrel

How did the real Snake Venom versus Squirrel Blood game evolve? Obviously, natural selection played a role on the squirrel side but it doesn’t explain how or why the snake venom got fined-tuned per squirrel population, says Holding.

It’s a complex and fascinating system with lots of other questions to ask.

Adding to the mystery is the fact that another study, also done by Ohio State scientists and published in the journal Toxicon, showed similar co-evolution in Ohio’s Eastern gray squirrels (Sciurus carolinensis). Those living in rattlesnake-free Columbus (home of The Ohio State University) did poorly (they died) against timber rattlesnakes (Crotalus horridus) in a park south of the city where other Eastern grey squirrels survived the bites.

What’s next? Stay tuned for Venom versus Blood II: Revenge of the Bushy Tails.

rocky 570x228
I don't have to outsmart a snake ... I just have to outrun a moose

Paul Seaburn

Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.

Join MU Plus+ and get exclusive shows and extensions & much more! Subscribe Today!