Science, Tech, Math › Animals & Nature Apes Scientific name: Hominoidea Share Flipboard Email Print Howard Yang/Getty Images Animals & Nature Mammals Amphibians Birds Habitat Profiles Reptiles Wildlife Conservation Insects Marine Life Forestry Dinosaurs Evolution View More By Laura Klappenbach Ecology Expert M.S., Applied Ecology, Indiana University Bloomington B.S., Biology and Chemistry, University of Illinois at Urbana-Champaign Laura Klappenbach, M.S., is a science writer specializing in ecology, biology, and wildlife. our editorial process Laura Klappenbach Updated March 17, 2019 Apes (Hominoidea) are a group of primates that includes 22 species. Apes, also referred to as hominoids, include chimpanzees, gorillas, orangutans, and gibbons. Although humans are classified within the Hominoidea, the term ape is not applied to humans and refers instead to all non-human hominoids. In fact, the term ape has a history of ambiguity. At one time it was used to refer to any tail-less primate which included two species of macaques (neither of which belong to the hominoidea). Two subcategories of apes are also commonly identified, great apes (which includes chimpanzees, gorillas, and orangutans) and the lesser apes (gibbons). Characteristics of Hominoids Most hominoids, with the exception of humans and gorillas, are skilled and agile tree climbers. Gibbons are the most skilled tree-dwellers of all hominoids. They can swing and leap from branch to branch, moving quickly and efficiently through the trees. This mode of locomotion used by gibbons is referred to as brachiation. Compared to other primates, hominoids have a lower center of gravity, a shortened spine relative to their body length, a broad pelvis, and wide chest. Their general physique gives them a more upright posture than other primates. Their shoulder blades lie on their back, an arrangement that imparts a wide range of motion. Hominoids also lack a tail. Together these characteristics give hominoids better balance than their closest living relatives, the Old World monkeys. Hominoids are therefore more stable when standing on two feet or when swinging and hanging from tree branches. Like most primates, hominoids form social groups, the structure of which varies from species to species. Lesser apes form monogamous pairs while gorillas live in troops numbering in the range of 5 to 10 or more individuals. Chimpanzees also form troops that can number as many as 40 to 100 individuals. Orangutans are the exception to the primate social norm, they lead solitary lives. Hominoids are highly intelligent and capable problem solvers. Chimpanzees and orangutans make and use simple tools. Scientists studying orangutans in captivity have shown them capable of using sign language, solving puzzles, and recognizing symbols. Many species of hominoids are under threat of habitat destruction, poaching, and hunting for bushmeat and skins. Both species of chimpanzees are endangered. The eastern gorilla is endangered and the western gorilla is critically endangered. Eleven of sixteen species of gibbons are endangered or critically endangered. The diet of hominoids includes leaves, seeds, nuts, fruit, and a limited amount of animal prey. Apes inhabit tropical rainforests throughout parts of western and central Africa as well as Southeast Asia. Orangutans are found only in Asia, chimpanzees inhabit west and central Africa, gorillas inhabit central Africa, and gibbons inhabit southeast Asia. Classification Apes are classified within the following taxonomic hierarchy: Animals > Chordates > Vertebrates > Tetrapods > Amniotes > Mammals > Primates > Apes The term ape refers to a group of primates that includes chimpanzees, gorillas, orangutans, and gibbons. The scientific name Hominoidea refers to apes (chimpanzees, gorillas, orangutans, and gibbons) as well as humans (that is, it ignores the fact that humans prefer not to label ourselves as apes). Of all hominoids, the gibbons are the most diverse with 16 species. The other hominoid groups are less diverse and include chimpanzees (2 species), gorillas (2 species), orangutans (2 species), and humans (1 species). The hominoid fossil record is incomplete, but scientists estimate that ancient hominoids diverged from Old World monkeys between 29 and 34 million years ago. The first modern hominoids appeared about 25 million years ago. Gibbons were the first group to split from the other groups, about 18 million years ago, followed by the orangutan lineage (about 14 million years ago), the gorillas (about 7 million years ago). The most recent split that has occurred is that between humans and chimpanzees, about 5 million years ago. The closest living relatives to the hominoids are the Old World monkeys.