Q&A

This month’s panel

BIOLOGY

Which animals can regenerate?

Autotomy, also known as self-amputation, is a somewhat counterintuitive but potentially life-saving behaviour, which has evolved in numerous animal groups. This last-ditch defence against predators is used by many invertebrates, as well as by some mammals, amphibians and reptiles. But while shedding a body part is one thing, being able to regenerate it is another one altogether. Salamanders and newts are unique among vertebrates in their ability to regenerate missing parts, including the limbs, eyes and tail. Lizards can regrow a functional tail, but it often differs markedly in appearance and contains cartilage rather than bone. Meanwhile, salamanders and newts reproduce a perfect replica. Their secret involves the formation of a blastema (a mass of cells) containing cells capable of differentiating into many types, including muscle and bone cells. The formation of theLaurie Jackson