In a recent article in American Scientist, Dr. Craig Stanford reported that chimpanzees from the 45 member Kasakela community of Tanzania's Gombe National Park hunt more than previously thought. Stanford estimates that the chimps eat one ton of meant on average each year. During one hunting binge in 1992, the chimps were observed to kill 71 red colobus monkeys in 68 days. He estimates that the chimps impact on the red colobus population each year is about one-fifth of the popultion. The level of predation is surprising but is less than that observed for human hunter-gatherers. Stanford notes, however, that chimps can consume up to a quarter pound of meat a day when their hunting activities are at their hieght. Pygmies in Zaire are among the lowest meat consumers of the human spectrum and their consumption is about equat to that of the Gombe chimps for at least periods of the year.
Building on the findings of Geza Teleki who noted that male chimps will exchange meat for sex with females, Stanford notes that chimps appear to hunt as a way to finance thier sexual barter when traveling with sexually active females. He believes this is a means of lower ranking males of obtaining sexual access. Scientists have already noted that consumption of meat by a female can benefit her offspring's health. Stanford believes this edge not only provides more sexual access for lower ranking males but also benefits the female and her offspring nutritionally.
As a side, the most prolific hunter in the Kasakela troop has killed 42 colobus in a five year period.