Evolution of Investment in Immatures in Adult Male Japanese Macaques (Macaca fuscata)

NOA COHEN, KYLEN N. GARTLAND and FRANCES J. WHITE Noa Cohen, Kylen N. Gartland, and Frances J White. Department of Anthropology, University of Oregon. 1585 E 13th Ave, Eugene, OR 97403

Adult male investment in immatures is uncommon in non-human primates and varies from costly infant-carrying in callitrichids to affiliation in cercopithecines. Several evolutionary hypotheses can explain the variation in care behaviors. The paternal investment hypothesis (PIH) proposes that adult males use kin detection to direct care towards genetically-related immatures. The mating effort hypothesis (MEH) proposes that adult males direct care towards immatures to influence female mate choice. We conducted 512 hours on focal males in semi-free ranging Japanese macaques (Macaca fuscata) at Oregon National Primate Research Center (ONPRC). Males varied in immature-directed behaviors from minimal interaction to frequent immature-carrying. We constructed hypothesis models based on the MEH, PIH and null hypothesis using generalized linear mixed models with a Gaussian distribution, including male ID as a random effect. We used multi-model inference testing to assess which model best explained variation in this behavior between adult males and determined the best model(s) using a ΔAIC < 2. Our preliminary results showed the ΔAIC for MEH as 3.73, PIH as 3.95 and the null as 0.00. Only the null was a significant model based on ΔAIC, suggesting that variation in this behavior is best explained by individual difference rather than differences in paternity relationship or mating success. However, non-significance in our evolutionary models demonstrates that although investment does not result in higher reproductive success than non-investing males, it was not significantly lower. Therefore, investment in immatures may be an alternate way to achieve the same reproductive success as non-investing, aggressive, dominant males.

Funding was provided to the ONPRC by NIH P51 OD011092.

Additional Abstract Information

Presenter: Noa Cohen

Institution: University of Oregon

Type: Poster

Subject: Anthropology & Archeology

Status: Approved

Time and Location

Session: Poster 1
Date/Time: Mon 1:30pm-2:30pm
Session Number: 2027