Mantled howling monkeys (Alouatta palliata) form dominance hierarchies and readily subgroup within multimale/multi-female groups (Chapman, 1990; Sanchez-Villagra et al., 1997). What is less understood is the extent to which age-sex class affects group spacing patterns. In baboon groups (Papio cynocephalus ursinus), for example, adult males disperse themselves much further apart than do other group members, especially lactating females, perhaps as a result of male reproductive strategies (Cowlishaw, 1999). Throughout July, 2012, I examined age-sex class spacing patterns in three groups of mantled howling monkeys in Ometepe, Nicaragua. The hypotheses were: 1) females with dependent infants spend more time close (within one meter) to other group members than do other adult females; and 2) adult males spent the least amount of time close to other adults. I collected forty hours of fifteen-minute individual scan samples on groups composed of two to nine individuals. Data supported both hypotheses. Whereas females with dependent infants were close to other group members in 65.9% of all samples (n=554) other adult females spent only 31.1% of samples (n=843) close to other howlers. Adult males spent the least amount of time, 9.4% of samples (n=1005) close to other howlers. As I observed little male-male competition for females, I suggest that these spacing patterns reflect heightened vulnerability and energy needs of howler mothers, and decreased vulnerability of adult males.

Semester/Year of Award

Spring 2012


Benjamin Z. Freed

Department/Professional Affiliation

Anthropology, Sociology, and Social Work

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Restricted Access Thesis

Degree Name

Honors Scholars


Anthropology, Sociology, and Social Work