Undergraduate Honors Theses

Thesis Defended

Spring 2011

Document Type




First Advisor

Herbert H. Covert


The relationship between forest structure and positional behavior is examined in the mantled howling monkey (Alouatta palliata) in primary and secondary rainforest habitats in northeastern Costa Rica. Despite structural differences between the two study sites, there are no significant differences in habitat use or positional behavior frequencies. Overall, the mantled howler monkey locomotor repertoire is centered on quadrupedalism and bridging, with sitting and suspension as predominant feeding postures. Howlers prefer small and medium horizontal supports, and use the upper and lower canopy frequently. Several methodological factors may have limited the results and analysis of this study. Temporally, the study was limited to the wet season, which may have implications for positional variability. A lack of distinction between travelling and foraging behaviors may have influenced the data. The study sites may also not have been distinctive enough to accurately reflect the influence of forest structure on positional behavior. The results were similar to those of a number of other studies of A. palliata, and are comparable with the positional behavior of the species and the genus as a whole. Without data from a more diverse array of mantled howler habitats, it is difficult to analyze site-specific intraspecific variation through cross-study comparisons. Previous discussions of intraspecific positional behavior variation in A. palliata have relied on cross-study comparisons, which can be problematic. Ultimately, the relative resilience of howlers to anthropogenic disturbance has been noted for some time, and the possible positive implications of this study are discussed. Further standardized research is necessary to fully examine intraspecific positional behavior variation.