A predictable pattern of daily activity by the pocket gopher Geomys bursarius

• Published in: Animal behaviour Vol. 48; no. 3; pp. 501 - 509
• Main Author: Benedix, J.H.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.09.1994; Harcourt Brace Jovanovich Ltd
• Subjects: Animal behavior; Mammals
• ISSN: 0003-3472; 1095-8282
• DOI: 10.1006/anbe.1994.1271

Because subterranean mammals live in a microhabitat buffered from environmental extremes, it is often assumed that their daily activity patterns are weakly structured at best. The daily activity (time outside the nest) of a natural population of plains pocket gophers, Geomys bursarius, was examined using radiotelemetry. A bimodal pattern of activity was observed in which gophers were most likely to be active at night (2200-0600 hours) and in early afternoon (1300-1700 hours). Total daily activity averaged 400 min/day. Activity-bout length varied with time of day. Morning bouts were the shortest, afternoon bouts the longest, and bouts at night were of intermediate length. The overall pattern of activity was best explained as a mechanism for avoiding burrow temperature extremes. Gophers would have conserved energy by remaining in their nests in the morning when the burrows were coolest, and may have reduced the risk of hyperthermia by avoiding activity in the late afternoon when burrows were warmest. Because an endogenously controlled circadian metabolic rhythm has never been demonstrated in pocket gophers, the observed pattern of activity was probably environmentally induced. The results suggest that the subterranean microhabitat may require efficient use of both time and energy by its mammalian inhabitants.