Meeting Abstract
58.2 Thursday, Jan. 6 Scrub lizard sprinting performance in field and lab ANDERSON, R.A.*; BALDWIN, K.S.; Western Washington Univ.; Monmouth College Roger.Anderson@wwu.edu
An understanding of locomotor adaptedness in terrestrial vertebrates presumably is best achieved by a combination of analyses of locomotion 1) on natural substrata in the microhabitats they typically occupy in the field and 2) in standardized conditions in the lab. Because lizards vary greatly in microhabitats used, vary by four orders of magnitude in mass, and vary in form from gracile to robust, with variable combinations of intergirdle, leg, pes, and digit lengths, they are particularly well suited to studies of locomotory capacity. Unlike most members of the genus Sceloporus that typically scamper on boulders and bark, the Florida scrub lizard S. woodi spends its activity period primarily on sand in open microhabitats, and appears to be an unusually fast-running lizard. This small ambush predator appears to be more gracile than close congeners. We measured maximal velocities and long run velocities of field-fresh lizards during bipedal evasion runs on natural sand substratum in the field during the summer. In lab we measured maximal, long-run, and recovery velocities of these lizards. Velocities in field raceways varied with mite load and body size. Lizards with three mites or less had maximum velocities that averaged about 2.7 m/sec (ranged 2 to 4 m/sec). Fast run distances averaged 16.5m. Some individuals were held in lab to enable recovery from mite infestations three weeks, and again sprinted in the field raceway, then held in the lab until spring and were sprinted on oval raceways in lab. Maximum velocities in field and lab velocities were similar, at about 3.3m/sec, with field velocities as high as 4.65 m/sec. Velocities varied directly with recovery time after long, fast runs. Sprinting velocity after recovery reached 90% of maximum at 28 minutes, but lizards could run at 2 m/sec after just 8 minutes. Sceloporus woodi is a remarkably fast lizard for its size.
