1/30/2024 0 Comments Chimpanzee teethBut because wood does not preserve well, the most ancient wooden spears ever found are only about 400,000 years old, leaving open the question of when such tools first came into use. Many suspect that the use of wooden tools far predates the use of stone tools - remnants of which have been found dating from 2 1/2 million years ago. Whether the animal was dead or alive at that point was unclear, but it did not move or make any sound.Ĭhimpanzees are believed to offer a window on early human behavior, and many researchers have hoped that the animals - humans' closest genetic cousins - might reveal something about the earliest use of wooden tools. In the successful bush-baby case, the chimpanzee, after using its sharpened stick, jumped on the hollow branch in the tree until it broke, exposing the limp bush baby, which the chimp then extracted. But that is reasonably efficient, Pruetz said, compared with standard chimpanzee hunting, which involves chasing a monkey or other prey, grabbing it by the tail and slamming its head against the ground. In only one of the 22 observations did a chimp get a bush baby. Then the chimp would break off a branch - on average about two feet long, but up to twice that length - trim it, sharpen it with its teeth, and poke it repeatedly into the hollow at a rate of about one or two jabs per second.Īfter every few jabs, the chimpanzee would sniff or lick the branch's tip, as though testing to see if it had caught anything. In a typical sequence, the animal first discovered a deep tree hollow suitable for bush babies, which are nocturnal and weigh about half a pound. Eventually the researchers documented 22 instances of spearmaking and use, two-thirds of them involving females. But in that instance she was unable to follow the chimpanzee to see what she did with it. "I just knew right away that she was making a tool," Pruetz said, adding that she suspected - with some horror - what it was for. Pruetz recalled the first time she saw a member of the 35-member troop trimming leaves and side branches off a branch it had broken off a tree. That environment is very much like the one in which early humans evolved and is different enough from other sites to expect differences in chimpanzee behaviors. Unlike other chimpanzee sites currently under study, which are forested, this site is mostly open savannah. Pruetz and Paco Bertolani of the University of Cambridge made the observations near Kedougou in southeastern Senegal. Others crumple leaves and use them as sponges to sop drinking water from tree hollows.īut while a few chimpanzees have been observed throwing rocks - perhaps with the goal of knocking prey unconscious, but perhaps simply as an expression of excitement - and a few others have been known to swing simple clubs, only people have been known to craft tools expressly to hunt prey. Some chimpanzees slide thin sticks or leaf blades into termite mounds, for example, to fish for the crawling morsels. Scientists have documented tool use among chimpanzees for decades, but the tools have been simple and used to extract food rather than to kill it. "Really fashioning a weapon to get food - I'd say that's a first for any nonhuman animal." The new observations are "stunning," said Craig Stanford, a primatologist and professor of anthropology at the University of Southern California. Pruetz of Iowa State University, adding that it reminded her of the murderous shower scene in the Alfred Hitchcock movie "Psycho." "It was kind of scary." "It was really alarming how forceful it was," said lead researcher Jill D. In one case, after repeated stabs, a chimpanzee removed the injured or dead animal and ate it, the researchers reported in yesterday's online issue of the journal Current Biology. Then, grasping the weapons in a "power grip," they jabbed them into tree-branch hollows where bush babies - small, monkeylike mammals - sleep during the day. Using their hands and teeth, the chimpanzees were repeatedly seen tearing the side branches off long, straight sticks, peeling back the bark and sharpening one end. The landmark observation also supports the long-debated proposition that females - the main makers and users of spears among the Senegalese chimps - tend to be the innovators and creative problem solvers in primate culture. The multistep spearmaking practice, documented by researchers in Senegal who spent years gaining the chimpanzees' trust, adds credence to the idea that human forebears fashioned similar tools millions of years ago. Chimpanzees living in the West African savannah have been observed fashioning deadly spears from sticks and using the tools to hunt small mammals - the first routine production of deadly weapons ever observed in animals other than humans.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |