The effects of social factors and kinship on co-sleeping in black-and-gold howler monkeys (Alouatta caraya)

BRIVIDORO MV; OKLANDER LI; CANTARELLI VI; PONZIO MF; FERRARI HR; KOWALEWSKI MM

INTERNATIONAL JOURNAL OF PRIMATOLOGY

SPRINGER/PLENUM PUBLISHERS

Año: 2021

0164-0291

Group cohesion at sleeping sites may have multiple functions in non-human primates,such as facilitating behavioral thermoregulation, social interactions, and reducing therisk of predation. Social, genetic and ecological factors influence association patternsduring sleeping. We explored the effects of sex, age-class, association during daytimeactivities (feeding, moving, resting, and social interactions including play, grooming andhowling), and kinship on sleeping cluster associations in a wild population of blackand-gold howler monkeys (Alouatta caraya). We collected behavioral data (mean =471 ± SD 34 observation hours/study group) and 29 fecal samples for genetic analysisfrom four groups inhabiting San Cayetano (27° 30 ´S-58° 41´ W), Corrientes, Argentina,for one year (June 2012-May 2013). Our results showed that black-and-gold howlerspreferred to sleep in clusters, and that the composition of these clusters was affectedby age-class and kinship. The probability of sleeping in clusters decreased withincreasing age of the individual. Daytime activities were not significant predictors ofnocturnal grouping. Dyads composed of mother-offspring, siblings and individuals thatwere not closely related to one another showed a high frequency of association fornocturnal sleep. Father-offspring dyads did not show statistically significant values ofnocturnal associations. This study highlights the social function of sleeping in clustersand suggests that primates develop a set of strategies that favors social affiliativerelationships between individuals in a nocturnal context.