California ground squirrels have a secret weapon against rattlesnakes, their natural enemy. The squirrels are now known to intimidate rattlesnakes by waving their tails.
Aaron Rundus studies animal communication at the University of Nebraska–Lincoln observed that when a rattlesnake is moving nearby, that squirrels will radiate heat from their tails. They wave the tail like a warning flag.
Rattlesnakes are very sensitive to infrared radiation, and this tail waving behavior puts the predator on the defensive.
Scientists took a different kind of approach to studying this in the lab: They built a robot squirrel, or what they call a robosquirrel. It’s a taxidermied squirrel stuffed with technology that allowed the researchers to control the body heat of the squirrel, and control its tail flagging. In the lab, they positioned the robosquirrel in front of a food source for the rattlesnake – and then they let the rattlesnake enter the chamber. The robosquirrel flagged its tail and the rattlesnake backed off. It was convinced. - Millet