A08: Non-maternal Adult- And Subadult-Infant Interactions in Wild Woolly Monkeys

Background
In many primates, males and/or non-lactating females are attracted to young infants and some may provide nonparental care (alloparenting) or engage in other forms of infant handling (holding, carrying, playing, and inspecting). The way in which these interactions play out may differ depending on varied factors (e.g. relatedness to the infant, dominance relationships, group dynamics, maternal tolerance for an individual). Here, we characterize all non-maternal adult and subadult interactions with infants in a population of wild woolly monkeys (Lagothrix lagotricha poeppigii).

Methods
Data were collected under the context of focal follows with nearest neighbors collected instantaneously every five minutes. All social interactions were recorded continuously, and important behaviors and interactions among non-focal animals were recorded ad libitum. We reviewed the Proyecto Primates long-term ateline behavioral database, and retrieved all instances of non-maternal adult or subadult interactions with infants recorded between 2014 and 2018.

Results
We retrieved 149 adult/subadult infant interactions from the database. Nearly all of these interactions (96%) were considered affiliative or tolerant (e.g., inspection, grooming, play, and crawling) and an overwhelming majority of interactions (96%) were between adult or subadult males and infants. Of the affiliative behaviors (N = 137) between males and infants, 89% of interactions were between adult males and infants and 11% of interactions were between subadult males and infants. There were only six agonistic interactions found, all occurring with adult males. Additionally, there were only six female interactions with infants (three AF, three SF); all were affiliative interactions.

Conclusions
Nearly all non-maternal infant interactions occurred with adult or subadult males. The paucity of female interactions likely reflects the egalitarian nature of woolly monkey society and the lack of kin relationships among females, while interactions by males may be driven by interest in determining paternity of young infants, especially if they have reason to believe that they are the sire.

Funding
Funding for this project was provided by Miami University and the Department of Anthropology through the Rebecca Jeanne Andrew Memorial Award, the Honors College, and Dr. Linda Marchant.

Author(s): Elisabeth Frank, Anthropology and Zoology Major Advisor(s): Kelsey Ellis, Department of Anthropology