From nest to nest—influence of ecology and reproduction on the active period of adult Gombe chimpanzees

Abstract

The time spent between sleeping periods, which is called the active period, has to accommodate all essential activities, including feeding, resting, social behavior, and reproduction. To minimize costs in terms of, e.g., predation risk, suboptimal foraging, or sleep deficiency, the active period of diurnal animals should be less than or equal to the daylight period. Thus, the active period of an animal should be shaped by local environmental conditions as well as by metabolic and reproductive demands. Chimpanzees, which exhibit reduced predator pressure and a flexible fission-fusion society, were chosen as a model to explore these links. We investigated the influence of sex, female reproductive status, dominance rank, and season on the duration of the active period of adult chimpanzees at Gombe National Park, Tanzania (1975-1992). Sexually nonreceptive females had shorter active periods compared to males, while receptive females had even longer active periods than males. Dominance rank did not influence the duration of the active period of nonreceptive females, but high- and middle-ranking males had shorter active periods compared to low-ranking males. Nonreceptive females exhibited longer active periods during the dry season than in the wet season. No seasonal effect was discovered for males, perhaps because they already had long active periods in the wet season. Nonreceptive females seem to be able to accommodate all essential activities in the daylight period available, probably because they live less socially than males. Thus, the active period does not reflect differences in female competitive abilities, but does reflect such differences in males. The duration of the active period appears to be a simple, reliable tool for exploring basic responses and constraints in animal societies.

Pedigrees and the Study of the Wild Horse Population of Assateague Island National Seashore

“…They include the red deer (Cervus elephas) of the Isle of Rhum, Scotland (CluttonBrock et al 1982), the Soay sheep (Ovis aries) of the St. Kilda archipelago, Scotland (Clutton-Brock and Pemberton 2004), the elephants (Loxodonta africana) of Amboseli National Park, Kenya (Moss 2001), and the chimpanzees (Pan troglodytes) of Gombe National Park, Tanzania (Lodwick et al 2004). These populations provide unparalleled windows into behavioral ecology, reproduction, population dynamics, and effects of natural selection, none of which can be studied in the short-term.…”

Influence of Ecological and Social Factors on Body Mass of Wild Chimpanzees

“…In a recent analysis of factors affecting the length of the active period (between descending from a nest in the morning and entering a nest at night), Lodwick et al (2004) found that lowranking adult males have significantly longer active periods than those of middle-and high-ranking males and suggest that they stay up later partly to compensate for the low food intake during contest competition; however, there was no effect for females.…”

A Retrospective Analysis of Factors Correlated to Chimpanzee (Pan troglodytes schweinfurthii) Respiratory Health at Gombe National Park, Tanzania

“…Several studies have reported seasonal differences in chimpanzee behavior which indicate that food is most abundant during the wet season (e.g., party size: Wrangham, 1977; activity budgets: Lodwick et al, 2004;body mass: Pusey et al, 2005). We followed the precedent of previous studies (Goodall, 1986;Wallis, 2002) and divided the year into quartile seasons to control for this known seasonal variation: the early wet (November-February), late wet (March-April), early dry (May-July), and late dry (August-October) seasons.…”