Seasonal variation in movement and activity patterns of Crotalus willardi obscurus in the Animas Mountains, New Mexico.

摘要

Movements by individuals of the New Mexico Ridgenose Rattlesnake, Crotalus willardi obscurus, at a site in the Animas Mountains were studied by telemetric methods over a multi-year period. Data are presented on a sample of 24 snakes in which transmitters had been implanted, all but nine of which were males. The results reveal that individual snakes were twice as active during the summer-fall monsoon (rainy season) than in the drier part of the warm season, a result consistent with non-telemetrically obtained observational data. Moreover, males showed greater distance movement per day than females in both seasons, although the sample size for females was too small to test for statistical significance. Such a gender difference has been suggested to occur in other snake species as the result of sexual selection, especially with respect to the energy conservation strategies associated with female reproduction. In the case of this rattlesnake, feeding efficiency and avoidance of predation may also be involved. Although the present telemetric study of movement in Crotalus willardi obscurus reveals no unexpected patterns of behavior for this snake, even this information contributes to the assembly a more complete picture of the biology of a poorly-known snake that will probably remain to be threatened at some level indefinitely.