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Gray, 1825
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Hylobatidae
Hominidae
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Apes are the members of the Hominoidea superfamily of primates, including humans. Currently, there are two families of hominoids:
- the family Hylobatidae consists of 4 genera and 12 species of gibbons, including the Lar and the Siamang, collectively known as the "lesser apes"
- the family Hominidae consisting of gorillas, chimpanzees, orangutans, and humans, collectively known as the "great apes".
A few other primates have the word "ape" in their name, but they are not regarded as true apes.
Except for gorillas and humans, all true apes are agile climbers of trees. They are best described as omnivorous, their diet consisting of fruit, grass seeds, and in most cases some quantities of meat and invertebrates—either hunted or scavenged—along with anything else available and easily digested. They are native to Africa and Asia.
Most ape species are rare or endangered. The chief threat to most ape species is loss of tropical rainforest habitat, though some populations are further imperiled by hunting for bushmeat.
Historical terminology
Ape (Old Eng. apa; Dutch aap; Old Ger. affo; Welsh epa; Old Bohemian op) is a word of uncertain origin and is possibly an imitation of the animal's chatter. The term has a history of rather imprecise usage. Its earliest meaning was a tailless (and therefore exceptionally human-like) non-human primate, but as zoological knowledge developed it became clear that taillessness occurred in a number of different and otherwise unrelated species.
The original usage of "ape" in English may have referred to the baboon, an African monkey. Two tailless species of macaque are commonly named as apes, the Barbary Ape of North Africa (introduced into Gibraltar), Macaca sylvanus, and the Sulawesi Black Ape or Sulawesi Crested Macaque, M. niger.
Biology
The great ape family was previously referred to as Pongidae, and humans (and fossil hominids) were omitted from it, but on grounds of relatedness there is no argument for doing this. Chimpanzees, gorillas, humans and orangutans are all more closely related to one another than any of these four genera are to the gibbons and siamangs. Awkwardly, however, the term "hominid" is still used with the specific meaning of extinct animals more closely related to humans than the other great apes (for example, australopithecines). It is now usual to use the subfamily Homininae to separate the hominids, in this narrow sense, from the extant non-human members of the family Hominidae.
Current evidence implies that humans share a common, extinct, ancestor with the chimpanzee line, from which we separated more recently than the gorilla line. All living members of the Hylobatidae and Hominidae are tailless, and humans can therefore accurately be referred to as bipedal apes. However there are also primates in other families that lack tails.
Both great apes and lesser apes fall within Catarrhini, which also includes the Old World monkeys of Africa and Eurasia. Within this group, both families of apes can be distinguished from these monkeys by the number of cusps on their molars (apes have five—the "Y-5" molar pattern, Old World monkeys have only four in a "bilophodont" pattern). Apes have more mobile shoulder joints and arms, ribcages that are flatter front-to-back, and a shorter, less mobile spine compared to Old World monkeys. These are all anatomical adaptations to vertical hanging and swinging locomotion (brachiation) in the apes.
Although the hominoid fossil record is far from complete, and the evidence is often fragmentary, there is enough to give a good outline of the evolutionary history of humans. The time of the split between humans and living apes used to be thought to have occurred 15 to 20 million years ago, or even up to 30 or 40 million years ago. Some apes occurring within that time period, such as Ramapithecus, used to be considered as hominins, and possible ancestors of humans. Later fossil finds indicated that Ramapithecus was more closely related to the orangutan, and new biochemical evidence indicated that the last common ancestor of humans and other hominins occurred between 5 and 10 million years ago, and probably in the lower end of that range. Ramapithecus therefore is no longer considered a hominin.
Cultural aspects
The intelligence and humanoid appearance of apes are responsible for legends which attribute human qualities; for example, apes are sometimes said to be able to speak but refuse to do so in order to avoid work. They are also said to be the result of a curse—a Jewish folktale claims that one of the races who built the Tower of Babel became apes as punishment, while Muslim lore says that the Jews of Elath became apes as punishment for fishing on the Sabbath. Christian folklore claims that apes are a symbol of lust and were created by Satan in response to God's creation of humans. It is uncertain whether any of these references is specifically to apes, since all date from a period when the distinction between apes and monkeys was not widely understood, or not understood at all.
New Species?
Also in 2002, a new giant ape troop was discovered in the Democratic Republic of Congo. These apes share many features of both chimpanzees and gorillas. According to a report from the BBC News Online, the apes have large black faces, are two meters tall and make nests on the ground, all like gorillas. However, they live hundreds of kilometers from any other gorilla troops, and their diet is high in fruits, similar to the chimpanzee diet.
History of hominoid taxonomy
The history of hominoid taxonomy is somewhat confusing and complex. The names of subgroups have changed their meaning over time as new evidence from fossil discoveries, anatomy comparisons and DNA sequences, has changed understanding of the relationships between hominoids. The story of the hominoid taxonomy is one of gradual demotion of humans from a special position in the taxonomy to being one branch among many. It also illustrates the growing influence of cladistics (the science of classifying living things by strict descent) on taxonomy.
As of 2005, there are eight extant genera of hominoids: Homo (humans), Pan (chimpanzees), Gorilla, Pongo (orangutans), and four genera of gibbons.
In 1758, Carolus Linnaeus, relying on second- or third-hand accounts, placed two species in Homo along with H. sapiens: Homo troglodytes ("cave-dwelling man") and the Homo caudatus ("tail-bearing man"). It is not clear to which animals these names refer, as Linnaeus had no specimen to refer to, hence no precise description. Linnaeus named the orangutan Simia satyrus ("satyr monkey"). He placed the three genera Homo, Simia and Lemur in the family of Primates.
The troglodytes name was used for the chimpanzee by Blumenbach in 1775 but moved to the genus Simia. The orangutan was moved to the genus Pongo in 1799 by Lacépède.
Until about 1960 the hominoids were usually divided into two families: humans and their extinct relatives in Hominidae, the other apes in Pongidae.
The 1960s saw the application of techniques from molecular biology to primate taxonomy. Goodman used his 1963 immunological study of serum proteins to propose a division of the hominoids into three families, with the (non-human) great apes in Pongidae and the lesser apes (gibbons) in Hylobatidae. The trichotomy of hominoid families, however, prompted scientists to ask which family speciated first from the common hominoid ancestor.
Within the superfamily Hominoidea, gibbons are the outgroup: this means that the rest of the hominoids are more closely related to each other than any of them are to gibbons. This led to the placing of the other great apes into the family Hominidae along with humans, by demoting the Pongidae to a subfamily; the Hominidae family now contained the subfamilies Homininae and Ponginae. Again, the three-way split in Ponginae led scientists to ask which of the three genera is least related to the others.
Investigation showed orangutans to be the outgroup, but comparing humans to all three other hominid genera showed that African apes (chimpanzees and gorillas) and humans are more closely related to each other than any of them are to orangutans. This led to the placing of the African apes in the subfamily Homininae, forming another three-way split. This classification was first proposed by M. Goodman in 1974.
To try to resolve the hominine trichotomy, some authors proposed the division of the subfamily Homininae into the tribes Gorillini (African apes) and Hominini (humans).
However, DNA comparisons provide convincing evidence that within the subfamily Homininae, gorillas are the outgroup. This suggests that chimpanzees should be in Hominini along with humans. This classification was first proposed (though one rank lower) by M. Goodman et. al. in 1990.
Classification and evolution
As discussed above, hominoid taxonomy has undergone several changes. Current understanding is that the apes diverged from the Old World monkeys about 25 million years ago. The lesser and greater apes split about 18 mya, and the hominid splits happen 14 mya (Pongo), 7 mya (Gorilla), and 6 mya (Homo & Pan)
- Superfamily Hominoidea
- Family Hylobatidae: gibbons
- Genus Hylobates
- Genus Bunopithecus
- Genus Symphalangus
- Genus Nomascus
- Family Hominidae: great apes
- Family Hylobatidae: gibbons
Legal status
Human beings are the only ape recognized as persons and protected in law by the United Nations Universal Declaration of Human Rights and by all governments, though to varying degrees. Chimpanzees, Gorillas and Orangutans are not classified as persons, which means that where their interests intersect with that of humans they have no legal status.
Many argue that the other apes cognitive capacity in-itself, as well as their close genetic relationship to human beings, dictates an acknowledgement of personhood. The Great Ape Project, founded by Australian philosopher Peter Singer, is campaigning to have the United Nations endorse its Declaration on Great Apes, which would extend to all species of chimpanzees, gorillas, and orangutans the protection of three basic interests: the right to life, the protection of individual liberty, and the prohibition of torture.
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This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. {{cite encyclopedia}}: Missing or empty|title=(help)
