Anthropogenic influences on the time budgets of urban vervet monkeys

Abstract

Continuing urban developments are ecologically changing many landscapes. A greater understanding of how wildlife adapt behaviorally to these changes is necessary to inform management decisions. Time is a valuable resource to wildlife and a reflection of ecological pressures on the behavioral repertoire of an animal. Data on urban vervet monkey, Chlorocebus pygerythrus, time budgets are generally limited and dated. We aimed to investigate the effect of anthropogenic influences, both human food consumption (positive) and human-monkey conflict (negative) on the time budgets of vervet monkeys in an urban landscape. We collected 20 min. focal animal observations and used generalized linear mixed models to assess the variation in time budget between five urban vervet monkey groups differing in anthropogenic contact over one year. We recorded anthropogenic interactions ad lib. as positive and negative. Our results showed seasonal influences across all behaviors. Furthermore, anthropogenic disturbance influenced all aspects of time budget to some degree. We found a positive interaction effect between positive and negative human incidents on foraging, and a negative interaction effect on movement and social behavior. Overall, vervet monkeys exhibited behavioral flexibility in the urban landscape. We suggest a complex association of costs and benefits to urban living.

Interactions with humans impose time constraints on urban-dwelling rhesus macaques (Macaca mulatta)

“…Interestingly, some urban-dwelling populations have been shown to spend more time resting and engaging in social activities compared to less urban groups (Saj et al, 1999;El Alami et al, 2012;Jaman & Huffman, 2013;Koirala et al, 2017;Ilham et al, 2018;Thatcher et al, 2019). This suggests a potentially positive effect (rather than negative) of anthropogenic factors on animals' time budgets.…”

“…Furthermore, in areas degraded by human activities, animals might be forced to increase their travel time, thereby decreasing their resting and social time, either in order to avoid humans or because natural food sources become scarce (red deer, Cervus elaphus: Grover & Thompson, 1986;lion-tailed macaque, Macaca silenus: Menon & Poirier, 1996;tonkean macaque, Macaca tonkeana: Riley, 2007). In contrast, other studies reveal that animals that live and thrive in an anthropogenic environment tend to spend more time resting and socializing than groups living in less anthropogenic areas (e.g., vervet monkey, Chlorocebus pygerythrus: Saj et al, 1999;Thatcher et al, 2019;Barbary macaque: El Alami et al, 2012;rhesus macaque: Jaman & Huffman, 2013; assamese macaque, Macaca assamensis: Koirala et al, 2017;long-tailed macaque: Ilham et al, 2018). Such beneficial effects may be due to reliance on anthropogenic foods that tends to be higher in calories, more abundant, and more digestible than natural foods (Forthman-Quick, 1988;Rode et al, 2006;Riley et al, 2013;McLennan & Ganzhorn, 2017), and researchers argue that in this condition animals can spend less time feeding, and consequently increase their time spent resting and/or socializing (Jaman & Huffman, 2013).…”

Impact of anthropogenic factors on affiliative behaviors among bonnet macaques

“…If primates are constantly exposed to, and/or prefer consuming human food to natural food, individuals may spend more time foraging on anthropogenic food relative to natural food. Previous studies on primate populations that thrive in anthropogenic landscapes have revealed that such animals also spend more time resting and socializing than populations in less perturbed landscapes, likely due to the high caloric value of anthropogenic foods leading to less time spent consuming or in search of natural food (El Alami, Lavieren, Rachida, & Chait, ; Hockings, Anderson, & Matsuzawa, ; Jaman & Huffman, ; Koirala et al, ; Saj et al, ; Thatcher, Downs, & Koyama, ). By the logic of this free‐time hypothesis, individuals that forage more on anthropogenic food may also have more time (rather than less time, as in time‐constraints) or energy to invest in grooming and/or other affiliative interactions (Kaburu, Beisner, et al, ).…”

Living in the suburbs: Space use by vervet monkeys (Chlorocebus pygerythrus) in an eco‐estate, South Africa

“…We obtained repeated, reliable counts from five vervet monkey troops, with a mean troop size of 31.6 (±8.84 SD ) (Table ). All troops had access to permanent water sources; however, two troops had relatively more access to non‐natural foods than others (Thatcher, Downs, & Koyama, ). These two troops had significantly larger troop sizes than troops more reliant on natural food sources.…”

“…Research on primate behavioural flexibility in anthropogenic habitats has increased markedly since the 2000s; however, this only includes 17% of currently recognised species (McLennan, Spagnoletti, & Hockings, ). Therefore, while vervet monkeys are shown to persist in urban areas (Chapman & Fedigan, ; Horrocks & Baulu, ; McLennan et al, ; Patterson, Kalle, & Downs, , ,; Shimada & Shotake, ; Thatcher, Downs, & Koyama, , ; Wolfheim, ), the absence of urban spatial data has greatly curtailed the efficacy of vervet monkey management efforts in transformed landscapes like KZN. To date, most management decisions have been based on previous practices, public opinion and the suggestions of researchers both with and without relevant experience and knowledge of the local vervet monkey population (Simbithi Environmental Group, 2016 pers.…”