The rattlesnake has special infrared sensors and is able to sense the body heat of a smaller mammal prey and able to attack them easily. It can easily attack and kill a squirrel, but the California ground squirrel (Spermophilus beecheyi) has a secret weapon
that wards off the rattlesnake. The squirrel heats up its tail than waves it in the snake’s face, hence confusing the snake, making it think the squirrel is a bigger animal. The snake senses the heat with the infrared sensor (as shown in the video) and gets confused by the size of the squirrel.
When scientists first watched this, they didn’t know how it was possible. Other animals also may use this infrared weaponry to escape frompredators.
California Ground Squirrel
Graduate student Aaron Rundus and his supervisor Donald Owings of the University of California, used a $35,000 infrared camera and saw the interactions between the rattlesnake and the squirrel. The squirrel lets more red flow on its tail, and as a result it heats up and can be seen via an infrared camera. They puff up at their ends and shake them rattlesnake to make them appear larger.
"Tests with robotic squirrels confirmed that a warmed squirrel tail made rattlesnakes more likely to act defensively, say Rundus and Owings."
Scientists now believe these squirrels evolved to have this natural ability to ward of rattlesnakes.
Scientists also say the squirrels don’t heat up their tails when they encounter a gopher snake, for example, because the gopher snake doesn’t have the infrared sensor organ.