Biology ETDs

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Food habits and habitat selection were investigated in a snake community 1n northeastern Chihuahua, Mexico, from 1975 to 1977. A total of 418 snakes (20 species) was collected along Highway 16 from Villa Aldama to El Pastor. Examination of snake capture sites for the plant species present, and a study of structural characteristics of the vegetation and topographic features showed that snakes exhibited distinct habitat preferences. Rodent species present and their relative densities were assessed by 5400 trap nights at 18 trap stations.

Digestive tracts of 351 snakes of 16 species were examined and they yielded 153 food items. Rodents comprised 71.1% of the diets by frequency of occurrence, with lagomorphs, birds, reptiles, amphibians, and arthropods accounting for the remainder. The most important snake predators on rodents were Crotalus atrox, f. molossus, C. scutulatus, Elaphe subocularis, and Pituophis melanoleucus.

Food habits are discussed in relation to various parameters of the prey populations; i.e., abundance, habitats, size, aggressiveness, and diel activity. The relation between rainfall patterns and seasonal snake activity is examined and contrasted with activity patterns in other desert regions with different precipitation regimes. The relation between home range size and desert productivity is discussed.

The coexistence of mammal-eating snakes in this community is chiefly due to spatial habitat differences of predators which coincide with habitat variations of prey species, with different-sized snakes choosing optimal-sized prey.



Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

Norman J. Scott

Second Committee Member

James S. Findley

Third Committee Member

William G. Degenhardt

Fourth Committee Member

Roger Conant

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