On the lookout for some light holiday reading and stocking stuffers I came across this year’s Discover magazine’s 100 top stories of 2011. With stories ranging from neutrinos and Einstein’s theory of relativity to the life of Steve Jobs, Chimpanzees (Pan troglodytes) make the cover as “Chimp Hunters,” and come in at story number 19 out of 100!
Based on Lwanga et al.’s (2011) Primate population dynamics over 32.9 years at Ngogo, Kibale National Park, Uganda article in AJP, the Discover article provides a short synopsis of how chimpanzees have been hunting red colobus monkeys (Procolobus rufomitratus tephrosceles) to the brink of extirpation from the Ngogo region of Kibale National Park.
Lwanga et al. used census data for eight primate species over more than 30 years in Ngogo. During this time they estimated an almost 90% decline in the red colobus population of Ngogo, which was correlated with an increase in encounter rates with chimpanzee parties. The authors concluded that the combination of the unusually high population of chimpanzees in Ngogo and the unusually high rates of chimpanzee predation there is responsible for the decline in red colobus. What makes this research so interesting, and worthy of the Discover list, is that this appears to be the first documented case of a nonhuman primate population causing the demise of another nonhuman primate population. As a result the Ngogo primate community seems to be in a nonequilibrium state, changing from a community dominated by a folivorous (red colobus) and frugivorous omnivorous (redtail monkey) species to a community dominated by three frugivorous omnivorous species (chimpanzees, redtail monkeys and mangabeys). Such research emphasizes the role of long-term research of entire communities in understanding population-level, community-level, and ecological dynamics over time.