Search

Though insectivory by large-bodied gorillas may be unexpected, researchers have reported it in all populations of gorillas studied to date. Our study of 2 well monitored groups of western gorillas ( Gorilla gorilla gorilla) at Bai Hokou in Dzanga-Ndoki National Park, Central African Republic provides information on frequency and variability of termite consumption (the most commonly eaten insect) as well as some of the first direct observations of the behavior. Pooled data from both groups indicate termite feeding on 34% and 83% of days, through fecal analysis and feeding trails, respectively. Direct observations revealed that termite feeding occurred on 91% of the days for 1 group, in which the silverback fed on termites during 13% of all feeding scans, making termites the most commonly observed food item. The group that had a higher density of termite mounds in its home range consumed termites more frequently than the other group did. A higher proportion of fecal samples from the silverbacks contained termite remains than the ones from adult females and juveniles. Termite consumption was lower during the dry season, but it does not correlate with rainfall, measures of fruit availability, or fruit consumption. Displacements at termite mounds occurred more than expected, indicating that they are a patchy, sought-after food resource. Gorillas did not use tools to extract termites, but they used 2 different techniques to remove them from the cells. Though culture or social traditions may cause the variation in termite consumption across sites, further investigation of termite availability and consumption is necessary to rule out ecological and methodological explanations for observed variations. [ABSTRACT FROM AUTHOR]

We monitored the impact of habituation for tourism through changes in gorillas' behavior during the habituation process at Bai Hokou (Dzanga-Ndoki National Park, Central African Republic) from August 1996 to December 1999. From August 1998 onwards we focused on one gorilla group: the Munye. During the habituation process, it became increasingly easier to locate and to remain with the gorillas. Their initial reactions of aggression, fear and vocalization upon contact were replaced increasingly by ignoring us. Curiosity appeared to be an intermediate stage in the process. The way in which contacts with the Munye ended became more subdued over time. Regular daily contact is important in promoting habituation. Likewise, contacting gorillas while they are in a tree or in dense forest provides positive results compared to open habitat. Contacts within 10 m and contacts without forewarning the gorillas of observer presence, e.g., via tongue clacking, should be avoided. As of December 1999, habituation had progressed well; habituation of western gorillas is feasible. However, the gorillas experience negative effects during the habituation process, showing, for example, an increase in daily path length, and reactions of aggression, fear and vocalization upon contact. Impacts diminish over time. Given these and other potentially negative effects, the decision to begin habituation should not be taken lightly. [ABSTRACT FROM AUTHOR]