tale of lost tails: pseudoautotomy in the Neotropical snake genus Drymoluber (Serpentes: Colubridae)

• Published in: Canadian journal of zoology Vol. 92; no. 9; pp. 811 - 816
• Main Authors: Costa, H.C., Moura, M.R., Feio, R.N.
• Format: Journal Article
• Language: English
• Published: Ottawa NRC Research Press 01.09.2014; Canadian Science Publishing NRC Research Press
• Subjects: Animal defenses; Autotomy; Colubridae; comportement de défense; defensive behavior; Drymoluber; females; habitats; histoire naturelle; males; natural history; Physiological aspects; Predation; prédation; pseudautotomy; pseudoautotomie; risk; Sample size; Serpentes; Snakes; séparation de la queue; Tail; tail breakage; tropics; urotomy; Woodland Racer; Zoological research; Zoology; Brazil
• ISSN: 1480-3283; 0008-4301; 1480-3283; 0008-4301
• DOI: 10.1139/cjz-2014-0115

Pseudoautotomy (no spontaneous tail breakage without regeneration) occurs in the snakes Drymoluber brazili (Gomes, 1918) and Drymoluber dichrous (Peters, 1863) throughout their geographic range. Examination of 197 specimens of D.dichrous and 60 D.brazili show, respectively, a frequency of tail breakage (FTB) in 26% and 40% of specimens, similar or higher than observed for most species with pseudoautotomy. There is no sexual difference in FTB for D.brazili, and no relationship between tail breakage and snout–vent length (SVL). For D.dicrous, tail breakage is more frequently observed in males when specimens are <710 mm SVL, but for longer specimens, the FTB is higher in females; this strange pattern may not be explained by a single hypothesis. The FTB does not vary significantly between disjunct populations of D.dichrous, suggesting that they are subject to similar predation pressures and escape rates, or minor or no effect of habitat structure on predation risk. The FTB increases with SVL in D.dichrous (but not in D.brazili, probably due to sample size), which is an indication that as the snake grows, the chance of being injured increases and partial tail loss becomes an efficient defense. The multiple tail break hypothesis is not supported for the genus Drymoluber Amaral, 1930, remaining restricted to taxa with specialized pseudoautotomy.