Michael Anguiano, M.S.


Education: Bachelor of Arts in wildlife biology (May 2001)

Master of Science in ecology from San Diego State University

McNair Project: Efficiency of Movement and Speed with Reduced Tail Length in the Slender Glass Lizard (Ophisaurus attenuatus) (2000)

Mentor: Eva Horne, Ph.D.

Tail autotomy is the voluntary separation of some portion of an animal's tail as a result of a physical stimulus. This tactic is employed by many species of reptiles and amphibians as a means of escape from an attacking predator. Glass lizards are a group of legless lizards that belong to the genus Ophisaurus. The tail can make up about 2/3 the total length of these lizards and is their main source of locomotion. If a portion of their tail is lost it does not fully regenerate. Therefore, the loss of some amount of their tail could result in reductions in speed. Data to test this hypothesis were obtained by encouraging lizards down a Plexiglas track in three timed trials. Track dimensions were 190 cm long by 18 cm wide with the bottom covered by pegs 5 cm tall spaced 5 cm apart. The fastest velocity (cm/s) for each lizard was compared to total length using the Spearman-Rank correlation test. The results were opposite of the predicted hypothesis with total length and velocity being negatively correlated (p=0.03). The shorter the lizard, the faster it negotiated the track. Tail autotomy may cause lizards to undergo a behavioral change to compensate for the loss of their tail as a diversion to predators. As a result of the loss of this escape mechanism, the lizards may have to become faster in order to escape predators.