Not all snakes have rattles, but many snakes vibrate their tails as a way to scare of predators. This sound was actually captured by Dr. Allison who watched a wild fox snake vibrating its tail among leaves and weeds. The vibration of the tail against the dried brush helped create this almost rattle-like sound. Even though fox snakes are nonvenomous, this vibration and accompanying sound can help fool predators into thinking that they are a venomous rattlesnake. This helps keep predators, and humans, away.
Check out a clip from Dr. Allison’s video below to see (and hear) for yourself!