WASHINGTON — Chimpanzees living on the West African savanna have been observed fashioning spears from sticks and using them to hunt small mammals — the first routine production of deadly weapons observed in animals other than humans.

The chimps were repeatedly seen using their hands and teeth to tear the side branches off long straight sticks and peeling back the bark and sharpening one end of the sticks with their teeth, the researchers report in Thursday's online issue of the journal Current Biology. Then, grasping the weapon in a "power grip," they jabbed into tree-branch hollows where bush babies — small monkey-like mammals — sleep during the day.

After stabbing their prey, they removed the injured or dead animal and ate it.

Lead researcher Jill D. Pruetz of Iowa State University in Ames said it reminded her of the shower scene in "Psycho."

The new observations are "stunning," said Craig Stanford, a primatologist and professor of anthropology at USC.

"Really fashioning a weapon to get food — I'd say that's a first for any nonhuman animal."

Fellow researcher Paco Bertolani of Cambridge University in England saw an adolescent female chimp use a spear to stab a bush baby as it slept in a tree hollow, pull it out and eat it.

Pruetz thought it was a fluke, but then saw similar weapon- making herself "over the course of 19 days almost daily," she said.

It was typically females who displayed the behavior.

Pruetz and Bertolani were watching the Fongoli community of savanna-dwelling chimpanzees in southeastern Senegal.

Chimps are known to use tools to crack open nuts and fish for termites. Some birds use tools, as do other animals such as gorillas, orangutans and even naked mole rats.

The chimps' hunting method usually failed, the researchers said. The studied apes mostly eat fruit, bark and legumes.

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