Chimpanzee (Pan troglodytes verus) Behavioral Responses to Stresses Associated With Living in a Savanna-Mosaic Environment: Implications for Hominin Adaptations to Open Habitats

Anthropologists have long been interested in the behavioral ecology of nonhuman primates living in savannas given what we know of early hominin environments. As expected, chimpanzees in the Fongoli community in southeastern Sénégal show a unique suite of behavioral adaptations to stresses associated with their savanna habitat. While Fongoli chimpanzees are species-typical in certain regards, such as including ripe fruit in the diet during all months of the year, they also adjust their behavior to the particular stresses of this dry, hot and open environment. These behaviors include using caves as shelters during the dry season, soaking in pools of water during the hot, early rainy season, and traveling and foraging at night during maximum phases of the moon. Adult males of this 35-member community serve as focal subjects in a long-term study of the ecology and behavior of chimpanzees in a savanna-mosaic environment. Here, we report on Fongoli chimpanzee activity budgets, grouping behavior, and habitat use during the dry versus wet season based on over 2500 hours of observation from March 2005–July 2006. Findings support the hypothesis that ecological pressures associated with a savanna environment significantly affect great ape behavior. The Fongoli chimpanzees’ large home range (\u3e65km²) is sometimes used cyclically, with the community traveling as one large party, in contrast to the typical chimpanzee fission-fusion pattern. Combined with data on temperature in the various habitats within the savanna mosaic, results show that Fongoli chimpanzees minimize energy expenditure during the hottest months and at the hottest time of day by resting more and traveling less, in addition to selectively using small patches of closed-canopy habitats, such as gallery forest. They move significantly more during early hours of the hot, dry season specifically and range in smaller parties at this time compared to during the wet season. The stresses associated with a savanna-mosaic environment and chimpanzees’ behavioral adjustments to them have important implications for understanding early hominin behavior in similar environments

Laterality in Termite-Fishing by Fongoli Chimpanzees: Preliminary Report

Many studies in both free-ranging and captive apes have shown that some forms of laterality of hand function occur in non-human primates1. However, true handedness (sensu McGrew and Marchant2), when most individuals show a skew in hand preference in the same direction across different tasks, seems to be restricted to humans. Other hominoids appear unlateralized in simpler tasks, such as reaching, picking up objects, and grooming3, but they show hand preference for more complex tasks, such as tool-using2, 4, 5 or elaborate food processing6, 7. Laterality in termite-fishing8 has been studied only at Gombe, and the two published data-sets are congruent. McGrew and Marchant2, 9 reported that most (27 of 36) chimpanzees showed an individualized hand preference for right or left, as did Lonsdorf and Hopkins10 (16 of 17) for termite-fishing in the same community. No other data have been published for chimpanzee communities elsewhere. This study asks if termite-fishing by Fongoli chimpanzees is lateralized, shows hand preference (individuals are lateralized, but with no populational preference for either hand), or task specialization (all or most individuals use the same hand)

Allometry and Ecology of the Bilaterian Gut Microbiome.

Classical ecology provides principles for construction and function of biological communities, but to what extent these apply to the animal-associated microbiota is just beginning to be assessed. Here, we investigated the influence of several well-known ecological principles on animal-associated microbiota by characterizing gut microbial specimens from bilaterally symmetrical animals (Bilateria) ranging from flies to whales. A rigorously vetted sample set containing 265 specimens from 64 species was assembled. Bacterial lineages were characterized by 16S rRNA gene sequencing. Previously published samples were also compared, allowing analysis of over 1,098 samples in total. A restricted number of bacterial phyla was found to account for the great majority of gut colonists. Gut microbial composition was associated with host phylogeny and diet. We identified numerous gut bacterial 16S rRNA gene sequences that diverged deeply from previously studied taxa, identifying opportunities to discover new bacterial types. The number of bacterial lineages per gut sample was positively associated with animal mass, paralleling known species-area relationships from island biogeography and implicating body size as a determinant of community stability and niche complexity. Samples from larger animals harbored greater numbers of anaerobic communities, specifying a mechanism for generating more-complex microbial environments. Predictions for species/abundance relationships from models of neutral colonization did not match the data set, pointing to alternative mechanisms such as selection of specific colonists by environmental niche. Taken together, the data suggest that niche complexity increases with gut size and that niche selection forces dominate gut community construction.IMPORTANCEThe intestinal microbiome of animals is essential for health, contributing to digestion of foods, proper immune development, inhibition of pathogen colonization, and catabolism of xenobiotic compounds. How these communities assemble and persist is just beginning to be investigated. Here we interrogated a set of gut samples from a wide range of animals to investigate the roles of selection and random processes in microbial community construction. We show that the numbers of bacterial species increased with the weight of host organisms, paralleling findings from studies of island biogeography. Communities in larger organisms tended to be more anaerobic, suggesting one mechanism for niche diversification. Nonselective processes enable specific predictions for community structure, but our samples did not match the predictions of the neutral model. Thus, these findings highlight the importance of niche selection in community construction and suggest mechanisms of niche diversification

Chimpanzee (Pan troglodytes verus) Behavioral Responses to Stresses Associated With Living in a Savanna-Mosaic Environment: Implications for Hominin Adaptations to Open Habitats

Anthropologists have long been interested in the behavioral ecology of nonhuman primates living in savannas given what we know of early hominin environments. As expected, chimpanzees in the Fongoli community in southeastern Sénégal show a unique suite of behavioral adaptations to stresses associated with their savanna habitat. While Fongoli chimpanzees are species-typical in certain regards, such as including ripe fruit in the diet during all months of the year, they also adjust their behavior to the particular stresses of this dry, hot and open environment. These behaviors include using caves as shelters during the dry season, soaking in pools of water during the hot, early rainy season, and traveling and foraging at night during maximum phases of the moon. Adult males of this 35-member community serve as focal subjects in a long-term study of the ecology and behavior of chimpanzees in a savanna-mosaic environment. Here, we report on Fongoli chimpanzee activity budgets, grouping behavior, and habitat use during the dry versus wet season based on over 2500 hours of observation from March 2005–July 2006. Findings support the hypothesis that ecological pressures associated with a savanna environment significantly affect great ape behavior. The Fongoli chimpanzees’ large home range (>65km²) is sometimes used cyclically, with the community traveling as one large party, in contrast to the typical chimpanzee fission-fusion pattern. Combined with data on temperature in the various habitats within the savanna mosaic, results show that Fongoli chimpanzees minimize energy expenditure during the hottest months and at the hottest time of day by resting more and traveling less, in addition to selectively using small patches of closed-canopy habitats, such as gallery forest. They move significantly more during early hours of the hot, dry season specifically and range in smaller parties at this time compared to during the wet season. The stresses associated with a savanna-mosaic environment and chimpanzees’ behavioral adjustments to them have important implications for understanding early hominin behavior in similar environments.This is an article from PaleoAnthropology (2009): 252, doi:10.4207/PA.2009.ART33. Posted with permission.</p

Laterality in Termite-Fishing by Fongoli Chimpanzees: Preliminary Report

Many studies in both free-ranging and captive apes have shown that some forms of laterality of hand function occur in non-human primates1. However, true handedness (sensu McGrew and Marchant2), when most individuals show a skew in hand preference in the same direction across different tasks, seems to be restricted to humans. Other hominoids appear unlateralized in simpler tasks, such as reaching, picking up objects, and grooming3, but they show hand preference for more complex tasks, such as tool-using2, 4, 5 or elaborate food processing6, 7. Laterality in termite-fishing8 has been studied only at Gombe, and the two published data-sets are congruent. McGrew and Marchant2, 9 reported that most (27 of 36) chimpanzees showed an individualized hand preference for right or left, as did Lonsdorf and Hopkins10 (16 of 17) for termite-fishing in the same community. No other data have been published for chimpanzee communities elsewhere. This study asks if termite-fishing by Fongoli chimpanzees is lateralized, shows hand preference (individuals are lateralized, but with no populational preference for either hand), or task specialization (all or most individuals use the same hand).This is an article from PAN Africa News 14 (2007): 1. Posted with permission.</p