When you are a Prey Animal and Need to be Stealthy | The Sloth Conservation Foundation

Sloths avoid predators that hunt by sight by moving very slowly and carefully. They are so slow that their movements fall below the threshold that triggers the attention of most predators. It has been said that a gun could be fired next to a sloth’s head, and the animal wouldn’t even turn around, leading to speculation that sloths are deaf. However, when faced with a threatening situation, the sloth’s natural reaction is to stay completely still. They have evolved to not break stealth by reacting to sudden loud sounds.