Squirrels heat up their tails and wave them at heat-sensing rattlesnakes to keep the snakes away. Steve Mirsky reports.
Mongoose python fights get all the ink, but here in the US it’s squirrels and rattlesnakes that have a noteworthy and tempestuous relationship. One might even call the interaction heated. Literally. Because researchers have discovered that California ground squirrels heat their tails up as a signal to rattlesnakes to keep away from baby squirrels. The report is in the Proceedings of the National Academy of Sciences.
Squirrels wave their tails at snakes to appear bigger and ticked off. And it was known that squirrels waved their tales more vigorously in the dark than in daylight. Well, rattlesnakes can sense infrared radiation, aka heat. So researchers used an infrared camera to record squirrel rattlesnake encounters. They also recorded faceoffs between squirrels and gopher snakes, which cannot sense heat.
And they found that the squirrels heated up their tales somehow when dealing with rattlers. But squirrels didn’t bother to turn on the heat when they waved their tales at gopher snakes. So a heatable tail seems to allow squirrels to say to rattlesnakes, “Move along, things for you here are just too hot.”