Summary: Biological Journal oJ h e Linrrearr Sociely ( 1988), 34: 175- 190. With 2 figures
Behavioural variation in natural populations.
V. Morphological correlates of locomotion
in the garter snake (Thamnophis radix)
STEVAN J. ARNOLD
Department of Biology, University of Chicago, 940 E. 57th Street, Chicago, I1 60637,
ALBERT F. BENNETT
School of Biological Sciences, University of Calzfornia, Irvine, CA 92717, U.S.A.
Received Oclober 1987, accepkdJor publicalion 9 February 1988
A series of morphological and locomotor performance variables was measurcd in a population of
newborn gartcr snakes to determine whether performance capacity has a significant morphological
basis in these animals. Morphological traits measured were body length and mass, number of body
and tail vertebrae and numbers of vertebral abnormalitics. Locomotor performances included burst
and mid-distancc speed and distance and time crawled before anti-predator displays were assumed.
All performance variables were repeatable in daily replicate trials ( P < 0.001). Individual burst
speed, mid-distance spced, and distance crawled were significantly correlated pairwise ( P < 0.01).
Most morphological and performance variables had a significant mass dependence (static
allometry), although the effects were rather weak (r2 < 0.1, except for body length): largcr animals