Abstract # 13355 Poster # 97:

Scheduled for Thursday, August 22, 2019 06:00 PM-08:00 PM: (Alumni Lounge) Poster Presentation


INTRAGROUP DIFFERENCES IN SPATIAL RELATIONSHIPS BETWEEN ADULT FEMALE MANTLED HOWLER MONKEYS (ALOUATTA PALLIATA) WITH AND WITHOUT INFANTS IN NORTHEASTERN COSTA RICA

C. Doelling1,2 and L. Bolt3
1Northwestern University , School of Professional Studies, Evanston , IL 60208, USA, 2Maderas Rainforest Conservancy, Limon Province, Rita, Costa Rica , 3Department of Anthropology, University of Toronto, Toronto, Ontario, Canada
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For group-living animals with bisexual dispersal, adult social bonds are likely to be strongest between males and females. Mantled howler monkeys (Alouatta palliata) live in social groups where adults engage in alloparenting and infanticide. Females with infants may be expected to show closer relationships with males than with other females, to prevent infanticide. We predicted that when nearest neighbor occurrence for females with and without infants was compared, males would more often be nearest neighbors and in closer proximity to females with infants. We collected 20 hours of focal data on howler monkeys at La Suerte, Costa Rica, in January 2019. We used 30-min focal point sampling, with points taken each 2 minutes indicating nearest neighbor sex (male, female, female with infant) and distance. When females with and without infants were compared, we found differences in nearest neighbor sex (X2=13.4, p=0.001); females with infants had male nearest neighbors less often than expected, while females without infants had male nearest neighbors more often than expected. Females with infants were closer to all female nearest neighbors than males (F=7.8, p=0.001), while females without infants were closer to males and females with infants than to females without infants (F=21.8, p=0.000). Females with infants may seek close proximity to other females due to the adaptive benefits of alloparenting, which may aid in infant survival and increase female reproductive output.