Date of Award

Summer 8-9-2018

Document Type


Degree Name

Master of Arts (MA)



First Advisor

Andrea Baden

Second Advisor

Jessica Rothman

Academic Program Adviser

Diana Reiss


In primate societies, caring for infants involves nursing, protection, provisioning, and carrying - all energetically taxing states for mothers. The cost of holding and carrying clinging infants often constrains mothers from moving and traveling, potentially reducing their food and energy intake. Alternatively, when an infant is physically separated from their mother they are at risk of predation from birds of prey or other large mammals. This requires a high level of vigilance from mothers, often further deterring them from acquiring the food and energy that they need. Allomaternal care (AMC) is hypothesized to provide mothers with a way to safely detach from their infants to feed and forage, allowing them to replenish their depleted energy stores. This thesis aimed to test this idea by investigating the function of AMC in a wild, forest-living colobine (Colobus guereza). The objective of this study was to document the nature of AMC in C. guereza and to determine the potential feeding benefits for lactating mothers during AMC. Research was conducted in Kibale National Park, Uganda, where seven mother-infant dyads in three groups of C. guereza were observed during six consecutive months (from the beginning of July through the end of December, 2017) resulting in a total of 661 observation hours (N=864 AMC bouts). The average AMC bout length was 49 seconds (range=638 seconds, SD=0.01). Juveniles and subadults handled infants more often than adults (Mann-Whitney U, p0.05, Wilcoxon p>0.05). These results provide evidence that AMC in C. guereza gives lactating mothers the opportunity to replenish energy through feeding and resting without clinging infants.



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