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Author's School

Graduate School of Arts & Sciences

Author's Department/Program



Robert W. Sussman, Glenn C. Conroy, John G. Fleagle, Charles F. Hildebolt, Jonathan B. Losos, Jane E. Phillips-Conroy, D. Tab Rasmussen, Alan R. Templeton


English (en)

Date of Award


Degree Type

Restricted Access Dissertation

Degree Name

Doctor of Philosophy (PhD)


Ecological and behavioral data were collected over an annual cycle on one community of Varecia variegata rubra and on one group of Lemur fulvus albifrons in the Andranobe Watershed, Masoala Peninsula, Madagascar. For V. v. rubra, minimum community size ranged between 18 and 31 individuals, animals have a multi-female/multi-male social structure, a fission-fusion type of social organization, and an exclusive, communally defended home range of 57.7 ha. For L. f. albifrons, group size ranged between seven and 11 individuals, animals have a multi-male/multi-female social structure, a cohesive type of social organization, and a non-exclusive home range of 13.1 ha. Feeding trees used by V. v. rubra females are spatio-temporally patchy, whereas feeding trees used by V. v. rubra males are patchy spatially but not temporally. Relative to V. v. rubra, food trees used by L. f. albifrons are less patchy both spatially and temporally. L. f. albifrons feeds in smaller food patches than V. v. rubra in every season. V. v. rubra females minimize forest area used and distances traveled during the food scarce cold seasons and gestation. Both V. v. rubra females and males show tactics for conserving energy in activity budgets and microhabitat use during the food scarce cold seasons and gestation. Sex differences in ranging patterns, activity budgets, diet, and use of forest sites reflect high energetic costs of reproduction in V. v. rubra females. These results are consistent with the hypothesis that V. v. rubra would show energy conservation tactics and sex differences in a variety of ecological variables corresponding to spatio-temporal patchiness of food and to reproductive stages. L. f. albifrons shows energy conservation tactics in activity budgets and use of forest sites, but not in horizontal or vertical ranging. Few sex differences are evident. This pattern is consistent with the hypothesis that L. f. albifrons would show fewer energy conservation tactics and sex differences due to its relatively lower reproductive costs and less spatio-temporally patchy diet. Niche separation between V. v. rubra and L. f. albifrons is effected via use of different forest strata, forest heights, and dietary differences. V. v. rubra ranges primarily above fifteen meters in tree crowns and has a diet consisting mainly of ripe fruit in every season. L. f. albifrons ranges primarily below fifteen meters in a wide array of forest sites in the understory and lower canopy and supplements a diet of fruit with substantial amounts of mature leaves, young leaves, flowers, and other items. Where comparisons with other studies of wild V. variegata are possible, similar ranging patterns and microhabitat use are observed despite variation in social organization. These findings suggest that the flexible social organization of V. variegata is an adaptive response to its reproductive biology and foraging ecology. Comparisons with other studies of wild L. fulvus indicate that this species is ecologically flexible. Different populations vary in diet, forest sites, forest heights, and activity pattern in response to local conditions and to accommodate less ecologically flexible sympatric species.


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