Geckos and other lizards can not only shed their tails to confuse predators (or people), but their tails' movements suggest they literally have a mind of their own, Canadian researchers have found.

The scientists found that the shed tails of leopard geckos don't just move in rhythmic reflexes, but also show complex movements, like lunges and jumps.

The tail "has an intricate repertoire of varied and highly complex movements, including acrobatic flips up to three centimetres in height," said Anthony Russell, a biology professor at the University of Calgary.

These movements are co-ordinated by a part of the spinal cord inside the tail. The signals controlling the movements begin at the end of the tail, suggesting that some kind of control centre is located there. The control centre's signals are usually over ridden by the lizard's brain, until the lizard decides to leave the tail behind.

"The most plausible explanation is that the tail relies on sensory feedback from the environment. Sensors on its surface may tell it to jump, pivot or travel in a certain direction," said Tim Higham, a former University of Calgary student who is now an assistant professor of biology at Clemson University in North Carolina.

The study on the nervous system of separated gecko tails show that it could serve as a model for studying complex nerve function in the spinal cord in the absence of signals from the brain, such as in a spinal cord injury.

"The gecko tail may be an excellent model for understanding the spontaneous activity that is sometimes observed following partial or complete spinal cord injury," said Russell.