Human diets are sometimes substantially different from that of other hominoids due in part to the development of technology and a wide range of habitation.

[9] Thus, the term "ape" obtained two different meanings, as shown in the 1911 Encyclopædia Britannica entry: it could be used as a synonym for "monkey" and it could denote the tailless human-like primate in particular.

Sir Wilfrid Le Gros Clark was one of those primatologists who developed the idea that there were trends in primate evolution and that the extant members of the order could be arranged in an "ascending series", leading from "monkeys" to "apes" to humans.

Modern taxonomy aims for the use of monophyletic groups for taxonomic classification;[16][f] Some literature may now use the common name "ape" to mean all members of the superfamily Hominoidea, including humans.

For example, in his 2005 book, Benton wrote "The apes, Hominoidea, today include the gibbons and orang-utan ... the gorilla and chimpanzee ... and humans".

Although the hominoid fossil record is still incomplete and fragmentary, there is now enough evidence to provide an outline of the evolutionary history of humans.

Genetic analysis combined with fossil evidence indicates that hominoids diverged from the Old World monkeys about 25 million years ago (mya), near the Oligocene–Miocene boundary.

Recent evidence has changed our understanding of the relationships between the hominoids, especially regarding the human lineage; and the traditionally used terms have become somewhat confused.

This recent turmoil (of history) illustrates the growing influence on all taxonomy of cladistics, the science of classifying living things strictly according to their lines of descent.

Linnaeus may have based Homo troglodytes on reports of mythical creatures, then-unidentified simians, or Asian natives dressed in animal skins.

In a letter to Johann Georg Gmelin dated 25 February 1747, Linnaeus wrote: It is not pleasing to me that I must place humans among the primates, but man is intimately familiar with himself.

[30]Accordingly, Johann Friedrich Blumenbach in the first edition of his Manual of Natural History (1779), proposed that the primates be divided into the Quadrumana (four-handed, i.e. apes and monkeys) and Bimana (two-handed, i.e. humans).

Recently many of our best naturalists have recurred to the view first propounded by Linnaeus, so remarkable for his sagacity, and have placed man in the same Order with the Quadrumana, under the title of the Primates.

The justice of this conclusion will be admitted: for in the first place, we must bear in mind the comparative insignificance for classification of the great development of the brain in man, and that the strongly marked differences between the skulls of man and the Quadrumana (lately insisted upon by Bischoff, Aeby, and others) apparently follow from their differently developed brains.

Further, in comparison with Old World monkeys, hominoids are noted for: more mobile shoulder joints and arms due to the dorsal position of the scapula; broader ribcages that are flatter front-to-back; and a shorter, less mobile spine, with greatly reduced caudal (tail) vertebrae—resulting in complete loss of the tail in extant hominoid species.

Note there are primates in other families that also lack tails, and at least one, the pig-tailed langur, is known to walk significant distances bipedally.

It has been hypothesized that in both incidents it was a mutation that occurred in apes living in Europe when the climate was getting colder, leading to starvation during winter.

The mutation changed the biochemistry of the apes and made it easier to accumulate fat, which allowed the animals to survive longer periods of starvation.

[37][38] Major studies of behaviour in the field were completed on the three better-known "great apes", for example by Jane Goodall, Dian Fossey and Birutė Galdikas.

These studies have shown that in their natural environments, the non-human hominoids show sharply varying social structure: gibbons are monogamous, territorial pair-bonders, orangutans are solitary, gorillas live in small troops with a single adult male leader, while chimpanzees live in larger troops with bonobos exhibiting promiscuous sexual behaviour.

In November 2023, scientists reported, for the first time, evidence that groups of primates, including apes, and, particularly bonobos, are capable of cooperating with each other.

[39][40] Apart from humans and gorillas, apes eat a predominantly frugivorous diet, mostly fruit, but supplemented with a variety of other foods.

Chimpanzees in different parts of Africa have developed tools that are used in food acquisition, demonstrating a form of animal culture.

The chief threat to most of the endangered species is loss of tropical rainforest habitat, though some populations are further imperiled by hunting for bushmeat.

[47] Currently considered to be the greatest threat to survival of African apes, Ebola infection is responsible for the death of at least one third of all gorillas and chimpanzees since 1990.