Heads or tails? Chance and probability in a test of the ‘spare tail’ hypothesis in lizards — ASN Events

Heads or tails? Chance and probability in a test of the ‘spare tail’ hypothesis in lizards (#353)

Bill Bateman 1 , Trish Fleming 2 , Lauren Gilson 1
  1. Curtin University, Perth, WA, Australia
  2. Murdoch University, Perth, WA, Australia

The ultimate anti-predator defence by lizards is tail autotomy.  Autotomy can only work efficiently if the predator directs its attacks towards the autotomisable part.  Researchers assume that this is the case for many lizards as they demonstrate behavioural tactics that emphasise the tail; for example some lizards move the tail independently of the body to draw attention to it or have coloured tails that make it more conspicuous. Such tactics may result in more predatory attacks but reduce the chance of the attacks being fatal.  Using plasticine models of both legged and legless lizards that varied in body size and/or tail length we explored the rate of predation and the likelihood of predation resulting in death or survival via autotomy.  The results support the ‘spare tail’ hypothesis where longer, more conspicuous tails result in less likelihood of a predatory encounter being fatal for the lizard.  We also discuss these finding in the light of previous research on tail investment in lizards across multiple taxa.