Ann Gibbons reports on the upcoming article in Current Biology:
[Jill] Pruetz's team, working at the Fongoli research site in the wooded savanna of Senegal, observed chimps breaking off green branches and in four cases using their incisors to sharpen the points. The chimps, which typically weigh 26 to 60 kilograms, were hunting nocturnal bush babies, 100- to 300-gram primates that hide by day in holes in trees. In all, Pruetz and Paco Bertolani, a graduate student at Cambridge University, documented 10 different chimps thrusting the tools into holes in 22 instances. "This is habitual," says Pruetz, whose team logged 2500 hours of observations.
Sucks to be a bush baby.
Gibbons A. 2007. Spear-wielding chimps seen hunting bush babies. Science 315:1063. doi:10.1126/science.315.5815.1063