Lizard's new tail

Source:, photo by R. Colin Blenis
A lizard can allow its tail to be broken off and then grow a new one. If a predator has a lizard by the tail, the reptile can survive by letting the appendage go. The new tail, however, is never as good as the old one.
It seems like a small sacrifice, leaving a tail behind to save your life. And when a new tail can grow back, this is certainly an option. But the new tail is nowhere near as good as the old one, according to new research.

The authors of the study discovered that the green anole lizard (Anolis carolinensis) can quickly grow a new tail, but that this regenerated tail is not a replica of the original. There are important anatomic differences between the two. In the new tail, the vertebrae are made of cartilage. The muscles in the new appendage are also much longer. The researchers suspect that the new tail is less flexible, as the interlocking bone vertebrae and shorter muscle fibres of the original tail allow its finer motor control. The new tail is thus a replacement to restore some of the functions of the old one.

The lizard’s regenerative capacity has fascinated scientists for quite some time. They hope to find out how the lizard does it, and which genes are responsible. The same genes in human cells might be able to be switched on. This would make it possible to stimulate growth of new muscle tissue or bone marrow in humans.

The study was published in the scientific journal The Anatomical Record.
Photo license: Creative Commons Attribution-Share Alike 3.0