Intra‐community coalitionary lethal attack of an adult male southern muriqui (Brachyteles arachnoides)

Abstract

We report on the first evidence of intra-community coalitionary lethal aggression in muriquis (Brachyteles). The event occurred in southern muriquis (Brachyteles arachnoides) during a long-term study (>15 years) of two social groups inhabiting mostly pristine Atlantic forest habitat in the Parque Estadual Carlos Botelho, southern São Paulo State, Brazil. The attack took place deep in the core area of the Group Caetê home range. Tense agonistic behaviors and vocalizations preceded the lethal coalitionary attack, and the tension increased over a 36-48 hr period. One adult female and two unidentified individuals also took part in a coalition led by six adult males. The members of the coalition collectively approached, embraced, immobilized and repeatedly bit the entire body of an adult male, resulting in severe bleeding injuries and the victim's death in less than 1 hr after the attack commenced. Combined ecological, behavioral and spatial data related to the event indicate that this was an intra-community attack and suggest social tensions related to mating competition as the proximate trigger of the coalitionary killing. The attack resembled those reported for chimpanzees, with clear numeric superiority and a low risk of injury to aggressors, resulting in the death of a lone conspecific victim. This observation (n=1) is suggestive of a capacity for escalated aggression in muriquis and reinforces arguments for the potential adaptive significance of intra-community aggression in male philopatric societies, as reported for spider monkeys and chimpanzees. These characteristics challenge the view of the muriquis as a peaceful primate and support the general hypothesis that imbalances of power contribute to intra-specific killing in primates, such as chimpanzees and humans.

Activity Patterns of Brachyteles arachnoides in the Largest Remaining Fragment of Brazilian Atlantic Forest

“…n for other genera = the number of populations meaned from Di Fiore and Campbell (2007) >75% of their feeding time consuming fruits, and the observed high fruit availability throughout the year in this habitat ) may explain why food availability had no effect on the time spent in different activities. In support of this suggestion, we observed relatively small-scale behavioral shifts between feeding and traveling, which appeared to be unrelated to food availability, but may have been related to local climatic conditions, or to dynamic individual characteristics such as reproductive costs (Talebi et al 2009) or differences in body size and hence energy balance (Ganzhorn et al 2009). Intra-and interspecific differences in activity patterns of Brachyteles and other Atelins (Table III) are likely to be the result of interacting factors such as food quality, its distribution, and foraging group size and composition (Strier 1991).…”

“…Overall, little is known on Brachyteles within the remaining continuous tracts of forest where the genus is still found. We assess the influence of ecological factors (seasonality and food availability) on time budgets, investigating how southern muriquis allocate their daylight time among different activities (feed, travel, rest, and socialize) on a daily, monthly, and annual basis in the Parque Estadual Carlos Botelho (PECB), the largest and relatively undisturbed remnant of Brazilian Atlantic Forest (Talebi et al 2009). Given the high plant diversity at this site (Custódio-Filho et al 1992), high temporal variability in temperature and food availability, and the large and diverse study troop , we predicted extensive variation in activity budget, with differences in diurnal activity cycles between austral summers and winters and an increase in resting time during periods of thermal stress.…”

Fission–Fusion Dynamics in Southern Muriquis (Brachyteles arachnoides) in Continuous Brazilian Atlantic Forest

“…Alternative mating strategies may also be apparent under high fissionfusion dynamics, which are absent in more cohesive northern muriqui populations. Large adult parties and private consortships (Talebi et al 2009) are male strategies in this population, allowing many or 1 male to copulate with ≥1 females away from the rest of the group. From the female's perspective, despite spending less time in mixed-sex parties and more time solitary vs males, frequent associations in larger mixed-parties may function to decrease the females' perceived risk of predation or infanticide, or reflect benefits accrued from information transfer of food resource locations.…”

“…The group, Group Caetê, consisted of 54 individuals (including 20 adult female and 18 adult males), occupying a range in the north-central section of PECB (Talebi et al 2009). Owing to the difficulties in determining group size in species with fissionfusion dynamics, we obtained this minimum value by summing the maximum daily counts for each age-sex class across months (Chapman 1988).…”

Relato de caso de morte por agressão entre macacos-prego <i>Sapajus nigritus</i> (Primates: Cebidae) no Jardim Botânico do Rio de Janeiro

“…Interações agressivas resultando em morte têm sido relatadas em primatas não-humanos como chimpanzés (Wrangham, 1999;Watts & Mitani, 2001), gorilas-da-montanha (Watts, 1989), colobus-vermelhos (Starin, 1994), Muriqui-do-sul (Talebi et al, 2009) e também em caiararas (Miller, 1998;Gros-Louis et al, 2003), e em macacos-pregos (Ramírez-Llorens et al, 2008;Scarry e Tujague, 2012). A manutenção do monopólio sobre os recursos alimentares na área de vida e/ou sobre as potenciais parceiras reprodutivas, são fatores que exercem forte pressão sobre animais sociais, principalmente em primatas, fazendo com que os animais invistam em interações agonísticas intensas.…”