Ecological Constraints On the Social Development of Vervet Monkeys

Abstract

Abstract1. Immature animals from three social groups of vervet monkeys (Cercopithecus aethiops) living in adjacent territories were observed in Amboseli National Park, Kenya. Measures of diets and food densities suggested that food quality and distribution differed both between the groups and between the dry and wet seasons, such that the dry season was a period of low food quality, and Group A had the lowest food density. 2. Seasonal differences in dietary quality and the time spent feeding produced seasonal differences in the rates of high energy social interactions: play, aggression, and competition. 3. Differences between groups in food availability and quality affected rates of social interactions such that Group A generally had the lowest frequency of interactions. Both between groups and between seasons, low food quality reduced the frequency of interactions and increased the time spent feeding. 4. Play rates were shown to be highly responsive to the energy estimated to be available from the diet during the different seasons such that play was eliminated from the immature social repertoire during the stressful dry season. 5. The time course of weaning also appeared to be influenced by seasonal and inter-group differences in habitat. Few females gave birth in consecutive years, and many suckled their infants into the second year of life. Stressed females weaned infants earlier. It is suggested that prolonged investment is a response to environmental variation and plays an important role in female reproductive strategies. 6. It is suggested that the immatures in these groups maximised the time and energy available for different types of social interactions in a different way in each season and in the different groups. This social flexibility may be viewed as part of an adaptive complex of behaviour during the immature stage of a life history.

Activity Patterns in Free-Ranging Samango Monkeys (Cercopithecus mitis erythrarchus Peters, 1852) at the Southern Range Limit

“…As food abundance declined in summer, juveniles showed a concurrent de cline in play activities and an increase in rest ing activities. Lee [44] recorded a similar rela tionship between play and grooming behav iour among juvenile vervet monkeys (C. aethiops). The adult male samango, in particu lar.…”

African Elephant Play, Competence and Social Complexity

“…Play, as has been shown for a range of species (e.g., primates: Baldwin & Baldwin, 1974;Lee, 1984;Sommer & Mendoza-Granados, 1995;ungulates: Krachun, Rushen, & de Passillé, 2010;Miller & Byers, 1991;ground squirrels: Nunes, Muecke, Anthony, & Batterbee, 1999;meerkats: Sharpe et al, 2002), is an excellent measure of environmental conditions. Play rates decreased markedly during droughts, although we were unable to detect a direct correspondence with energy intake through suckling or independent calf feeding.…”

Opportunistic mothers: female marmosets (Callithrix kuhlii) reduce their investment in offspring when they have to, and when they can

“…One pattern of early weaning, or reduced maternal investment in offspring, was associated with maternal inability to maintain offspring growth or lactation due to low resource availability or poor physical condition. Indeed, early weaning (e.g., vervet monkeys, Cercopithecus aethiops: Lee, 1984Lee, , 1987Hauser and Fairbanks, 1988), unresponsive and neglectful parenting (e.g., vervet monkeys, Hauser, 1993;human: Belsky et al, 1991; also see review in Maestripieri and Carroll, 2000), infant abuse and abandonment (e.g., humans: Daly and Wilson, 1984;Hrdy, 1999), and infant mortality (e.g., barbary macaques, Macaca sylvanus: Ménard and Vallet, 1993;humans: Daly and Wilson, 1984;Hrdy, 1999) have all been associated with poor maternal condition and/or poor resource availability. In such cases, females may sacrifice their current offspring's fitness in favor of maternal survival and the possibility of producing offspring in the future.…”