The Influence of Extremes of Temperature on Activity Patterns of Peccaries

Abstract

The ecological determinants of activity patterns of peccaries (Dicotyles tajacu Linnaeus) were studied in Big Bend National Park, Texas, from June 1972 to April 1974. Cessation of feeding activity and initiation of bedding were found to be negatively correlated with minimum daily temperature (r2 = 0.51). The colder the preceding night and early morning (minimal temperatures were generally reached at about 0500) the later into the morning peccaries fed before bedding for the day. Depending on temperature, peccaries bedded from 0800 to approximately noon. Onset of feeding activity in the afternoon was correlated with maximal daily afternoon temperatures (r2 = 0.64). As maximal temperatures increased in the summer, peccaries remained in their bed progressively later into the day. .During the winter months peccaries left their beds in the early afternoon (1500), whereas during the hottest summer months activity was seldom initiated before 1700-1800. In desert habitats, peccaries exhibit seasonal variation in their movement and feeding patterns (Eddy 1961; Ellisor and Harwell 1969; Schweinsburg 1969; Bigler 1974). Activity patterns of peccaries have been reported previously (Jennings and Harris 1953; Bigler 1974; Day 1968, 1970, 1971a, 1972a, 1974a) but the relationships were not verified statistically. The purpose of this study was to examine the relationship between daily ambient temperature and the activity patterns of peccaries. STUDY AREA. The study was conducted in Big Bend National Park, in southwestern Texas on the Mexican border. Big Bend is situated in the northeastern portion of the Chihuahuan Desert and is comprised of the forested Chisos Mountains, low desert, and riparian vegetation along the Rio Grande. Although peccaries were found throughout the Park, the study site encompassed only an area of desert and foothills adjacent to the northeastern portion of the 1 Oklahoma Cooperative Wildlife Research Unit, 404 Life Sciences West, Oklahoma State University, Stillwater, Oklahoma 74074.