Tail loss, tail color, and predator escape in <i>Eumeces</i> (Lacertilia: Scincidae): age-specific differences in costs and benefits

The tail loss adaptation in Eumeces of the southeastern United States is complex. Juveniles possess tails that are colored differently from those of adults and apparently distract the attention of potential predators from the body to the tail. Adult tails are cryptically colored. Frequency of tail loss is high across size groups. Experiments on growth of tailed and tailless juveniles suggest no effect of tail loss on growth and, thus, there may be little cost of tail loss to juveniles other than the temporary loss of the autotomy adaptation. Lipids in adult tails constitute nearly 50% of total standing lipids and are reduced during reproduction similar to other lipid reserves. This suggests that tail loss in adults is expensive, particularly prior to or during the breeding season. We suggest that the high costs of tail loss in Eumeces are offset by the increased probability of predator escape via tail loss. Tail loss data are minimal estimates of escape via distraction of a predator's attack to the tail as indicated by predation experiments. The presence, coloration, and behaviors of the tail may result in a high proportion of predation attempts being redirected to the tail followed by total misses.