Like some other animals, the gecko can perform a neat trick when threatened by a predator: it can amputate its own tail. The dropped tail serves to distract the predator, and by losing it, the lizard can run faster.

But the tail doesn’t just sit there. It can make movements for up to half an hour. Timothy E. Higham of Clemson University and Anthony P. Russell of the University of Calgary have now studied those movements in detail. An amputated gecko tail, they report in Biology Letters, can swing back and forth and even flip into the air.

Dr. Higham said he was interested in trying to understand the motor patterns in the tail, which appear to be coming from neurons in the spinal cord that make up what is referred to as a central pattern generator, or C.P.G. “It’s similar to what happens in other vertebrates,” he said. “The problem is to study them, you have to disconnect the spinal cord from the head.”

The lizard disconnects its spinal cord on its own, in a harmless way. Just a pinch near the base is all it takes to cause the gecko to drop, or autotomize, its tail.