Coluber constrictor

Abstract: eastern Missouri, U.S.A. Milwaukee Pub. Mus. Contrib. Biol. Geol. 67:1-19. , AND S. R. HUNT. 1980. Temperature relationships and movements of snakes (Elaphe obsoleta, Coluber constrictor) in a cave hibernaculum. Herpetologica 36:20-26. , AND K. R. MARION. 1981. Experimental analysis of movements by prairie rattlesnakes, Crotalus viridis, during hibernation. Oecologia 51:37-41. SOKAL, R. R., AND F. J. ROHLF. 1981. Biometry. 2nd ed. W. H. Freeman & Co., San Francisco, California.

Abstract: Summary 1. Energy requirements explain substantial variation in movement and home range size among birds and mammals. This study assesses whether the same is true of snakes by comparing ratsnakes (Elaphe obsoleta) and racers (Coluber constrictor), ecologically similar species whose energy requirements appear to differ substantially (racers > ratsnakes). 2. Over 4 years 22 Elaphe and 16 Coluber were radio-tracked at the same site in Illinois to examine how movement and home ranges varied by sex and season. 3. Coluber moved more often and further per move than Elaphe, resulting in their estimated mean day range being almost four times larger than that of Elaphe (88-0 m day"1 vs. 23-1 m day"1). 4. Both male and female Elaphe moved more frequently early in the season consistent with mate searching, but mean distances moved did not differ seasonally or by sex. Both sexes of Coluber moved more later in the season and overall males moved further than females. 5. Interspecifically, patterns were consistent with the energetics hypothesis - Coluber had mean home ranges approximately four times larger than those of Elaphe. 6. Intraspecifically, increased movement did not always produce larger home ranges. Male Elaphe had larger home ranges than females despite not moving further, whereas male Coluber had comparable home ranges to females despite moving further. Also, Elaphe home ranges in Illinois were substantially smaller than has been documented in Ontario, despite Ontario Elaphe moving less. 7. Our results generally support the energetics hypothesis, but indicate that knowledge of ecology and

Abstract: Phylogenetic relationships among major clades of advanced snakes and the origin of the front-fanged venom systems of elapids and viperids have been the focus of considerable study and debate during the past century, but a general consensus on the resolution of these questions has not been reached. Here we compare DNA sequences of portions of the mitochondrial small and large subunit ribosomal RNA genes for representatives of three major clades of advanced snakes: an elapid (Naja naja), a viperid (Vipera ammodytes), a colubrine (Coluber constrictor), and, for an outgroup, a boid (Boa constrictor). Phylogenetic analysis indicates a close relationship between the elapid and colubrine relative to the viperid. This finding is congruent with the immunological data of Cadle (1988). Essentially no support was found for the hypothesis of a single origin for frontfanged venom systems and sister status for viperids and elapids, as first proposed by Cope (1900). The hypothesis of a basal position for elapids, as proposed by McDowell (1986), was refuted. T WO major groups of snakes possess large, muscular, temporal venom glands and subocular venom ducts leading to front fangs. Elapidae (cobras, kraits, coral snakes, sea snakes, and their allies) constitutes one group, Viperidae (vipers and pitvipers) the other. With the possible exclusion of a small number of prob

Abstract: Differences in snake color pattern have been demonstrated to affect behaviors involved in antipredator defense. Snakes with blotched or banded color patterns are concealed when not moving, and tend to rely on concealment and aggression for defense. In contrast, snakes with uniform or striped color patterns are easily seen when stationary, but their speed and direction are difficult to track when moving. They tend to rely on flight for protection. Some snake taxa exhibit ontogenetic change in color pattern, but the behavioral consequences of this change have not been investigated. I present results of a behavioral study in the racer, Coluber constrictor, which has a blotched juvenile color pattern but is uniformly colored as an adult. Hatchling racers were significantly more likely than adults to show aggressive behavior when confronted with a model predator, whereas adults were more likely to flee. This supports the hypothesis that changes in behavior and color pattern are correlated in this species to provide effective antipredator defense at different stages of life history. I also examined sprint speed, which may be an important factor in antipredator defense. Juvenile and adult racers showed a similar relationship between length and speed, a pattern also seen in other species that lack color change. This result suggests that sprint speed is not a causal factor in the evolution of ontogenetic color change.