Social cost of tail loss in Uta stansburiana: lizard tails as status-signalling badges

Abstract

Individuals of many lizard species lose tails to escape predation, but incur later costs, including reduced social status. Since size relates strongly to social rank in lizards, experiments were devised to separate effects of reduced size from other aspects of tail loss on social status following loss of tail. Tail removal from dominant subadult side-blotched lizards, Uta stansburiana, lowered social status in dyadic encounters. Artificial restoration of tail length restored social status in females but not males, largely due to the dimorphic response of subordinate lizards. Subordinate females displayed the same social relation to former dominant opponents with restored tails, whereas they increased aggression towards former dominant opponents without restored tails. Subordinate males responded equally to both kinds of former dominant opponents. Females, but not males, appear to use the tail as a status-signalling badge, or indicator of resource-holding potential. Females may assume an alternate social role once the tail is lost.