Bonobo

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(CC) Photo: Matthew Bietz; Stephen Ewen
A bonobo.

The Bonobo (pan paniscus) is a part of the [Hominidae] family which also includes the [Chimpanzee], the [Gibbon], the [Gorilla], the [Orangutan], and the Human. This species of ape can be found in a relatively small region: the lowland rain forest along the [Congo River} in [The Republic of the Congo]. It lives in communities that range from 30 to 100 individuals that occupies areas 22 to 60 square km. Each community is broken up into parties, and these parties are made up of 12 to 15 individuals, however the membership is always in fluctuation.

What is in a Name?

The Bonobo has commonly been linked to the chimpanzee as a "Pygmy Chimpanzee" however this classification has been deteriorating in use due to the fact that the name gives false implications about the species. The pygmy portion of the name was given after a study of a Chimpanzee's bones and a Bonobo's bones. The study found the latter to be more gracile in comparison to the former's, thus the name was given. However the Bonobo is in fact an entirely seperate species from the Chimpanzee, in fact it is as closely related to them as humans are. According to Mitochondrial DNA research the Chimpanzee and Bonobo species likely split from each other about 1.5 to 2 million years ago.

Features

Body and Build

The Bonobo is a [quadruped], meaning that it walks on all four limbs rather than two like us. A unique feature to this quadruped's walking is in the use of it's knuckles. Rather than walking on the palm of it's hands the Bonobo puts all of it's weight onto it's knuckles, thus termed: knuckle walking. Due to this form of walking and the extensive arboreal lifestyle it leads, the fingers and toes of the Bonobo are slightly curved. This species of ape, unlike others, has very little [sexual dimorphism]. The male weighs an average of about 39 kg and the female about 31 kg. Despite the small difference in weight, when standing erectly both sexes are about the same height. At birth the Bonobo has darker skin and entirely black fur, this remains this way until old age, in which some gray can be seen. An easy way to recognize the Bonobo from the Chimpanzee is to refer to it's hair. The hair on the top of it's head tends to flair out just above it's ears. When compared to Chimpanzees the Bonobo has less [prognathic|prognathism], in other words it's face is flatter. It's ears are also relatively smaller. If placed next to a Chimpanzee, it would become very apparent that the Bonobo has a slighter more gracile build. Making it's body weight about 20% less.

Skeletal Morphology

The skull shows some resemblance to that of a Chimpanzee adolescent. This lead anthropologists to further research on the Bonobo's skull. As a result, they found that it exhibits some [paedomorphic|paedomorphism] or youthful traits maintained through out life. The skull does not however show any signs of [sagital crest|sagital cresting] or [nuchal crest|nuchal cresting] that is sometimes observed in Chimpanzees and almost always in Gorillas. In comparison to the Chimpanzee's skull, the Bonobo has a relatively smaller brain case meaning a smaller cranial capacity. The Bonobo's overall more gracile build can be attributed to it's skeletal make up. Bonobos, when compared to Chimpanzee's, have narrower chests, smaller [clavicle|clavicles], elongated [scapula|scapulas] and shorter forelimbs and hindlimbs.

Famous Bonobos

Kanzi and his sister Panbanisha are two of the most famous Bonobos because of the experiments they have been involved in over the last two decades. They have have both been involved in extensive research in the use of language, many claiming they are close to a human level of comprehension. Kanzi is also famous for his development with tool making. See "Tool Making" in article for further information.

The Phylogeny Debate

Some researchers developed a theory about the Bonobo's skeletal make-up and it's surprising resemblance to that of the extinct Australopithecine's skeletal remains. After comparing the two, a hypothesis was created claiming that the Bonobo was the proto-form of these extinct hominid species. However many anthropologists objected to this idea. The Chimpanzee and Hominids diverged from each other about 5 million years ago, each taking separate evolutionary paths. The Bonobo did not diverge from the Chimpanzee until about 1.5 million years ago. This means that it's relation to the Chimpanzee is much closer than to the Australopithecines. One theory objecting to the Bonobo's relation to ancient hominids is that the build of the ape is actually an adaption to their unique ecological environment. This claim noted that the Bonobo's pelvis is suited for quadrupedal knuckle walking, whereas bipedalism was a defining factor in making the Australopithecines hominids. However the debate continues.