Doctoral Dissertations

Date of Award

8-1999

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Ecology and Evolutionary Biology

Major Professor

John L. Gittleman

Committee Members

Gary F. McCracken

Abstract

The kinkajou (Potos flavus) is a neotropical, nocturnal, arboreal and frugivorous member of the Procyonidae. Although they are common throughout much of their range,they have rarely been studied and very little is known about their ecology, behavior, or genetics. General natural history and morphological data suggests that the lifestyle of the kinkajou has converged in many ways with primates. This dissertation presents the results of field and laboratory research on a population of 25 free-ranging kinkajous in central Panama.The diet of the kinkajou is described from analysis of feces and observations of habituated individuals. Ripe fruit was the primary food comprising 90.6% of feeding bouts and present in 99% of feces. Leaves and flowers made up <10% of the diet. Noanimal prey was eaten. Seventy-eight species of fruit from 29 families were detected.Moraceae was the main plant family in the diet and Ficus was the most used plant genus.Kinkajous preferentially fed in large fruit patches. Selection indices were calculated for 37 fruit species. Compared with other large mammalian herbivores in central Panama the diet of kinkajous is most similar to the spider monkey (Ateles geoffroyi).The behavior of kinkajous is described from 380 hr of observations on habituated,free-ranging animals. Social groups (n = 5)were consistent in membership and included a single adult female, two adult males, a subadult and a juvenile. Some females did not live in this group structure. The social groups were consolidated primarily at denning sites and large fruiting trees via allogrooming, scent marking and vocalizations.However, kinkajous were more often solitary as they fed together in 19.6% of their feeding bouts and almost never traveled between feeding bouts in groups. Female biased dispersal and patterns of male association suggest that kinkajou groups are patrilineal and based on resource defense. The evolution of this social organization is discussed in respect to predation risk, resource availability, and convergence with primates of similar ecology. This study, along with others, now supports the idea that mammals with social organizations based on solitary living can reveal surprising flexibility, sociality, and complexity.Relatedness and paternity of the study population was estimated with data from11 microsatellite loci. Heterozygosity of the population at these loci was 0.43. With a combination of exclusion and likelihood analyses both parents for seven of the eight offspring sampled were assigned, five with ≥95% certainty, and to two with ≥80%certainty. Five of six identified sires of group offspring came from the same social groupas the mother and pup. Furthermore, males and females within a group were unrelated,illustrating the family nature of groups. Males pairs within a group could be relatedunrelated. All five identified sires were dominant males suggesting that one male a dominate breeding within a group. Neighboring male kinkajous were more closely related to each other than neighboring female kinkajous, suggesting that females disperse more often and/or further than males. These genetic results provide new detail about the paternity and relatedness of kinkajou social groups which strengthen explanations about the dispersal and patrilineal nature of kinkajou social organization made with limited or: canfield data.Food and predation are critical factors influencing the evolution of mammalian social organization. However, the relative importance of each remains equivocal and fewstudies have simultaneously measured these factors. In this dissertation the nocturnalVIactivity and grouping patterns of kinkajous are analyzed for adaptations to changing foodavailability (from bimonthly fruit census) and predation risk (from moonlight). Travelingwas the most frequent activity, followed by eating, resting and socializing. The averagedistance traveled per night was 2210 m. Females traveled significantly more (m and min)than males, whereas males were marginally more social. The daily activity patternshowed constant levels of activity throughout the middle of the night, with increasedtraveling at dusk and dawn. Variation in activity patterns reflected seasonal changes in fruit abundance. Females responded to changes in food availability by traveling more (mand min) and eating less as fruit increased, and feeding in larger trees and feeding groups as patches became farther apart. Overall, adjustments by males to seasonal fruit changes were not significant. However, outside the breeding season, males did respond significantly to increased fruit abundance by eating less and resting more. Both sexesreduce predation risk by resting more when the moon is bright, whereas males also travelless in bright moonlight. Changing fruit abundance had a more significant effect on activity budgets than did moonlight, suggesting that food abundance is more important than predation risk. This helps to explain the mostly solitary nature of kinkajous:individuals are not forced to form groups to reduce predation risk but change their subgroup size in response to varying levels of resource availability. Sex differences in response to feeding competition also correspond with different social and ranging patterns observed in male and female kinkajous.A comparison of the biology of kinkajous, spider monkeys (Ateles sp.), and chimpanzees (Pan troglodytes) shows that all three have evolved similar social solutions to the reduced predation, frugivory niche, but have reached it from different evolutionary origins. Ateles and Pan maintain their ancestral social nature, but have evolved smaller and flexible foraging groups that permit them to minimize feeding competition.Kinkajous maintain their mainly solitary ancestral nature, but have evolved a sociality permitted by their variable and patchy fruit diet. The patrilineal nature of all three social groups suggests that female dispersal and male sociality may also be favored by a diet of ripe fruit, perhaps related to resource defense by males.

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