It is already known that Chimpanzees ingeniously use tools for some tasks like obtaining invertebrate insects from logs or pounding open hard nuts, but researchers witnessed these gregarious anthropoid apes fashioning tools for authentic hunting, a spectacular observation that would help in shaping our understanding of how tool use has evolved among primates.

A team of researchers led by an anthropology professor Jill D. Pruetz of Iowa State University in Ames witnessed the Fongoli community of savanna-dwelling chimpanzees using spears to apparently hunt bush babies, the first routine production of deadly weapons ever observed in animals other than humans.

These omnivorous chimps were observed making spear-like tools in a step-wise fashion, and afterwards using them with jabbing motions in an apparent effort to obtain lesser bushbabies (Galago senegalensis) from cavities in hollow branches or tree trunks where these small monkey-like mammals sleep during the day.

It was only the female chimps who fashioned and used the wooden spears, Pruetz and Paco Bertolani, also from Iowa State University, reported. "It is not adult males, but young chimpanzees, including adolescent females, who are exhibiting this behavior," Pruetz said.

The US researchers, who witnessed the spearing of a bush baby, a small primate that lives in hollow branches or tree trunks, during an observation of chimpanzees from March 2005 to July 2006, reported their finding in February 22 online version of the journal, Current Biology.

Pruetz along with Bertolani, now at Cambridge University in Britain, documented 22 cases of chimps using spear-like tools to hunt bushbabies, two-thirds of them involving females.

According to the landmark study, the chimps were so many times seen tearing the side branches of long straight sticks, peeling back the bark and sharpening one end by using their hands and teeth, giving it shape like a skewer.

After repeatedly striking their prey with the pointed wooden rod, they removed the injured or dead animal and ate it, the study said.

Reminiscing observation of chimps hunt with skewer like tool, Pruetz reacted as "It was really alarming how forceful it was," adding that it reminded her of the murderous shower scene in the Alfred Hitchcock movie Psycho. "It was kind of scary."

Though the findings are stunning, but researchers in only one of 22 observations witnessed a chimpanzee extracting a bush baby by using a spear, making it unclear for some scientists whether the spectacle was a bit of luck or an indication that chimps have a more advanced ability to hunt than was thought.

Though the research duo only once witnessed a chimp get a bush baby, but Pruetz believes it is reasonably efficient, compared to standard chimpanzee hunting practice, which involves running after a prey, grabbing it by the tail and then forcefully hitting its head against the ground.

Iowa State University and the National Geographic Society had funded Pruetz's study.