The Feeding, Ranging, and Positional Behaviors of Cercocebus torquatus, the Red-Capped Mangabey, in Sette Cama Gabon: A Phylogenetic Perspective.

摘要

The feeding, ranging, and positional behaviors of Cercocebus torquatus (red-capped mangabey) were studied in Sette Cama, Gabon from 2008-2009. Several authors argue that hard-object feeding is the key adaptation of the Cercocebus-Mandrillus clade and that durophagy influences many aspects of Cercocebus social and behavioral ecology. This study evaluates the impact of obdurate foods on C. torquatus adaptation and evolution by combining multiple lines of evidence. Additionally, this information tests the hypothesis that C. torquatus is the most primitive member of its genus and that C. torquatus is a sister taxon to Mandrillus. .;C. torquatus in Sette Cama fed predominantly on fruits and seeds, but seed consumption was higher than that reported for other C. torquatus populations. The C. torquatus diet in Sette Cama was dominated by foods with intermediate to high hardness values and their foods were comparable in hardness values to those reported in other studies. The consumption of obdurate foods remained constant throughout the wet and dry seasons, and C. torquatus showed no preference for any food group. This suggests that durophagy is habitual among this population and does not serve as a fallback strategy.;C. torquatus in Sette Cama occupies a smaller home range than other Cercocebus species of similar group sizes. The ranging behaviors of C. torquatus were influenced by the seasonal distribution and availability of fruits, particularly the location of Sacoglottis gabonensis seeds. The lack of competing primate species in their habitat along with the intensive use of both terrestrial and arboreal resources by C. torquatus may explain their small home range. C. torquatus also frequently divided into subgroups.;C. torquatus spent the majority of time on the ground followed by the understory and forest canopy. Contrary to predictions based on phylogenetic relationships and morphology, C. torquatus is possibly one of the least terrestrial of all Cercocebus species studied. They used quadrupedal locomotion most frequently during travel and feeding followed by climbing and leaping. The most common postural behaviors were sitting and quadrupedal standing.;The feeding, ranging, and positional behavior data from this study supports a close relationship between C. torquatus, C. atys, and C. lunulatus within the Cercocebus-Mandrillus clade. C. torquatus and C. atys are similar in their large group sizes and reliance on hard-object foods such as Sacoglottis gabonensis seeds throughout the year. Previous cranio-facial studies specifically positioned C. torquatus as the sister taxon to Mandrillus. Nevertheless, the behavioral evidence suggests that C. atys occupies a more similar niche to mandrills than does C. torquatus..;This study does not refute the hypothesis that C. torquatus and Mandrillus are sister taxa. Their current sympatry and niche partitioning suggest they could have evolved from a common terrestrial ancestor by sympatric speciation. The recognition of a 1.5 to 2 million year old fossil species closely resembling C. torquatus and the behavioral ecology of C. torquatus suggests that the polarity of the features shared by C. torquatus and Mandrillus are ancestral rather than derived for this clade.