Evolutionary aspects of tail shedding in lizards and their relatives

Surveyed tail shedding across lizards and their relatives, examining the anatomy of the fracture planes, which groups have lost the ability, and how shedding relates to ecology and to the tail’s other functions.

Studied in

Squamata

Sample size

comparative survey across lizard families

Caudal autotomy occurs at preformed fracture planes within vertebrae, has been lost repeatedly in lineages where the tail serves other important functions, and its distribution tracks the balance between escape benefit and the tail’s other uses.

• A comparative survey; the correlations between ecology and autotomy are suggestive rather than experimental.
• Concentrated on lizards, though autotomy occurs across many invertebrate groups by different mechanisms.

• Autotomy

  Shedding a body part works — the animal escapes. What follows is worse locomotion, lost energy stores, slower growth, reduced breeding and, in several species, a drop in social standing.

• Autotomy

  A lizard does not drop its tail whenever it is frightened. The threshold rises and falls with how dangerous the situation is and what the tail is currently worth — and what regrows is a cartilage rod, not a tail.