Tool Use Of Chimpanzees

Tool Use Of Chimpanzees

I chose this topic because of all of the living primates, I would say that chimpanzees are the closest to ourselves. They are the most advanced of the living primates and have the most extensive tool use. I also chose it because I think the tool use of primates is the easiest way to distinguish between their cultures. I believe that through generations of trial-and-error tool discovery, and passing down behaviors, they have developed more advanced cultures then any other species, next to humans.It is interesting to me to think that this is how the evolution of humans started out with just a few primitive tools used for nutrition, grooming, intimidation, and defense. In a few million years, they could be evolved to our level. With that, where might we be at that point.One of the most interesting aspects but less common of their tool use is their ability to defend themselves with clubs, missiles, or stones. Some use theses just as show but some really mean business. It has been observed that only savanna chimpanzees are capable of any really effectiveness and accuracy while forest chimps while poorly aimed attempts of throwing are only used for show.It has been speculated that African apes are dehumanized descendents of savanna hominoids that were forced to retreat into the forests in the wake of hominid hunters who had invented spears. This brings the question of weather those were our early ancestors and if that chimps are nearly at that point in their evolution.

During thunderstorms , Gombe chimps get excited, break off or pick up and brandish branches a dash around precipitately in defense as if being alarmed at something. Occasionally, they would strike another chimp or another animal with their stick, often releasing just before striking. This, to me, seems to be a sign that they are ready to defend themselves from whatever danger is coming their way. During periods of excitement in banana feeding grounds, they threw sticks, stones, or handfuls of vegetation as part of displays directed towards other chimpanzees, baboons and humans. Less then half of the males that participated exhibited signs of actual aiming and rarely hit their target. They tried throwing both overhand as well as underhand. During the banana episode observed, as the frequency of aggression increased, more males engaged in it as well as youngsters as well as one adult female chimp. As it went on the ration of hit per miss increased as well.

This observation means to me that they might be conscious that they are tapping into a possible breakthrough but cannot yet realize the possibilities of what regular spear throwing could bring. I believe it is yet generations from possibly their true realization of the usefulness of the spears or “missiles”. It is becoming instinctive however but not yet as refined yet as is their tools for fishing termites.In a rare instance, a Gombe adult male, Mike, threw a sizeable rock (25cm x 10cm x 10cm) at a group of brush pigs, striking one. He and his companions had surrounded the pigs and when the pigs retreated into the brush, Mike and his companions caught a piglet and ate it. In an earlier observed instance, Mike had used a 4 gallon kerosene can to display and bluff his way into the pinnacle of the group, past the before leader, Goliath. Since that instance, he has been knocked from his position of power.

This tells me that there are chimps with a higher capacity to understand weapons and the abilities of them. He however didn’t fallow up on this as much as he could have. It is puzzling that they fear things like that but cannot grasp it enough to consistently use weapons for hunting and some other purposes.

In one observation in Bossou, chimps threw underhand sticks of 100-400 cm in length at their observers. Their effectiveness and accuracy unfortunately was evident on the observers. They would climb a branch into a position nearly right above the observers and hurl them underhand. After further observation, when the chimps were further accustomed to the human observers, they stopped throwing sticks at them. The only ones that still threw sticks at them were the younger chimps, throwing less menacing sticks of only 40-100 cm in length.This seems to be a good example of cultural diversity in chimps due to tool use. It seems to have been a more prominent part of their lives because they seem to have developed an actual technique to throwing their spears. It is unknown why they had become more accustomed to using spears or what they had been exposed to.

In a study of Zaire chimps, observers confronted them with large caged felines and a dummy stuffed leopard. When sticks and clubs were available, they would brandish clubs or throw the sticks at the potential attacking cats. I think that one of the most important traits that all chimpanzees could catch onto would be the use of weaponry. It could also cause them to branch off between the chimps who had developed spears and clubs. Those brandishing spears and clubs could run the more primitive chimps out of their area. It would be a big step in their evolution as it could have been a large step in our evolution.

Another important “branch” in the tool use of chimpanzees is their use of sticks as probes for fishing out insects as well as other things. This is an important part of most chimp’s daily lives with the exception of the chimps in Budongo who have not exhibited any tool use at all. I don’t believe that this has anything to do with their intellectual capacity but more to do with their need. The needs of their lives have been met and there is no need for growth of their culture. When the need comes to adapt, it will be survival of the fittest.Chimps have been observed using sticks, stems, slender twigs, strips of bark fiber, and vine sections to fish for alate termites. The average length being between six to twelve inches. Out of 145 tools measured in a study, their average length was 30.7 cm.

The chimps inspect the mounds on their daily rounds. Tools are inspected variable before, during, and after mound inspection. They searched no further then ten meters away to find a new tool to use as a probe but were noted to have brought used tools from old mounds up to 100 yards away. This tells me that they have a conscious plan and definitely know where they are going. Various tools are sometimes used sequentially to find the best ones. Their tools were modified; stems were denuded of leaves, wide grass or bark was divided longitudinally, frayed or bend ends were nipped off. They apparently have an idea of their tool and know what they are making.

Fishing tools aloud chimps first helpings on the termites. Birds, other monkeys, and baboons wait until time for their migration and they fly out of their mounds. This is a sign of the advanced intelligence exhibited by chimpanzees.

Gombe chimps were also observed using sticks to extract two species of ants from subterranean and arboreal nests. These sticks were observed to be between 1.5 and 3.5 feet in length and ripped off nearby vegetation or picked up off the ground.The chimps observed the previously raided nests and fallowed ants to pristine nests. When they spotted surface perturbations that indicated the presence of unraided subterranean nests, they dug rapidly into the nests with their hands and ants rapidly swarmed to the entrance in defense of their nest. To avoid being bitten, they would sit on logs, branches or saplings. They dash in, insert the smaller end of the probe in and twist it down tightly, then move away. They pull out the stick when it is about three quarters covered by the ants. The chimp then holds the ant covered end to their mouth and with their other hand, swiftly sweep the ants into their mouth and chew rapidly. The bunch is about the size of a hen’s egg and contains upwards three hundred ants.

This is an important trait of chimps because it is probably the most widely used tool throughout Africa. Probing ant and termite hills is one of the only tools uses observed in chimps in both eastern and western Africa.The drinking sop is another observation made in chimps. They insert wads of masticated leaves into tree holes and suck out the steeped liquid. This is observed in Gombe chimps to such the oil from palm oil trees.A very interesting behavior observed in chimps is the use of tools for hygene. It is hard to believe that any animal is conscious of their hygiene. I believe that chimps are however the closest thing to a human being that there is.

Several chimps in captivity were observed using sticks for oral hygiene. Infant chimps were observed using sticks as picks to clean out their noses. Other mature chimps used sticks as picks to clean out their teeth. The most interesting of these was a 9 year old female named Belle who became the regular dental hygienist for 4 other chimps. She employed her fingers as well as an assortment of handy wooden tools, one of which being a piece of red cedar denuded of leaves, used for picking foreign particles from the teeth. She even extracted a deciduous molar from the mouth of a patient supine male.Oral hygiene isn’t the only thing that chimps worry about. They also use leaves for various grooming purposes and toiletries. They were observed using plucked leaves to wipe mud, blood, feces, urine, and sticky food residue from honey and fruit juices from various parts of their bodies.

It is interesting that chimps are conscious of such things as grooming because some things just don’t seem practical. It seems that some of those behaviors could be pure vanity. I don’t see the hazard that could be caused by some things.Interest lies in another use of tools in the daily life of some chimps. Cracking nuts adds a new dimension to their intellect it seems, multiple tool use. The use of “hammer and anvil” is a more advanced behavior then it seems. It employs a cooperation of tools.

In the Sapo forest of Liberia, chimps are observed cracking 4 species of nuts: Coula edulis, Panda oleosa, Parinari excelsa, and Sacoglottis gabonensis. They pound with stone hammers of about 3.3 pounds on boulders and tree roots.On the Tiwai Island researches found cracked shells around hard tree roots with lacerations. They didn’t observe any chimps fleeing with stones in their hands and found no stones nearby that would be effective hammers but found several serviceable clubs nearby. They also found stone anvils with cracked shells scattered around them.

An interesting fact is that Gombe chimps are not observed cracking nuts. One of the most highly eaten nuts are the ones that come from the oil palm trees and the pulp from these trees make up a significant part of their diet. As well as the palm trees providing a good anvil for cracking the nuts.Due to the lack of hazard, younger chimps have been observed fishing for termites, wipe for toilet use, and sponge with leaves. They however do not get into ant dipping until later age. Their tool use is shown to be a learned trait from parents of chimps, primarily the mothers. This backs up my idea of cultures evolving through generations within their specific groups.At six months of age, the infant chimps are noticed reaching for twigs and leaves but are making no use of them, only mimicking their mothers. It is not until 8 months that they manipulate possible crude use but still do not use them. They don’t begin their termite dipping until they reach the age of 2. At 2 years of age, they select inappropriate tools and use them crudely and inefficiently. At three to four years of age, the novice termite fishers are improving but not yet as persistent as mature adults. It as at this age that they also develop into successful leaf spongers.

While their mothers are dipping for ants, they cling tightly to their mothers and watch intently but stay as far away from danger as they can. They have been observed practicing the ant dipping method away from ant hills. They aren’t usually successful ant dippers until they reach adolescence at 7 years of age. The youngest successful ant dipper, however, was observed at 46 months of age.An interesting observation made in captivity was that when face with problem solving situations to be solved with tools, the more mature and older chimps were more successful. Probably due to their practice with using tools throughout their life in non-problematic situations.

Sex also plays an important role in dietary tool use. Seventy-five percent of females engage in dietary tool use whereas only forty-five percent of males use tools for dietary purposes. Females engage in slightly longer bouts of termite dipping on average then do males. They also engage in more ant dipping sessions that last for more then one hour.The question of efficiency posses an interesting question. I believe that females will make more advancements in tools then will males because of more practice that they have at tool use. This clashes with some facts that it is the males that are making more advancements in tool use for weapons because nearly all males will pick up a weapon before a female. This poses an interesting question. I believe that the answer is in male aggression. The males are more aggressive then females and as such will be more likely to pick up a weapon.I believe that the tool use of chimps is what divides their specific cultures from one another. Some say that it is the feeding habits of them but that ties in directly with tool use. I believe that the dominant cultures of chimpanzees will be those that develop advanced weapons and those that don’t develop weapons will be pushed out or maybe not even survive. I believe this because it is what seems to separate our cultures in human civilization. It seems to be all about the ability to adapt to one another and built the better tools. That is what divides the men from the beasts and I believe that chimps are narrowing that gap more then any other primate or any animal.

Bibliography

Primate Behaviors, by Bernstein, Irwin S.; Academic Press; 1970

Apes of the World, by Tuttle, Russel H.; Noyes Press; 1986

www.cnn.com

www.wildchimps.org