Chimpanzee in the context of "Head louse"

The Hominidae (/hɒˈmɪnɪdiː/; hominids /ˈhɒmɪnɪdz/), whose members are known as the great apes, are a taxonomic family of primates that includes eight extant species in four genera: Pongo (the Bornean, Sumatran and Tapanuli orangutan); Gorilla (the eastern and western gorilla); Pan (the chimpanzee and the bonobo); and Homo, of which only modern humans (Homo sapiens) remain.

Numerous revisions in classifying the great apes have caused the use of the term hominid to change over time. The original meaning of "hominid" referred only to humans (Homo) and their closest extinct relatives. However, by the 1990s humans and other apes were considered to be "hominids".

The Hominini (hominins) form a taxonomic tribe of the subfamily Homininae (hominines). They comprise two extant genera: Homo (humans) and Pan (chimpanzees and bonobos), and in standard usage exclude the genus Gorilla (gorillas), which is grouped separately within the subfamily Homininae.

The term Hominini was originally introduced by Camille Arambourg (1948), who combined the categories of Hominina and Simiina pursuant to Gray's classifications (1825).

Laughter is a typically pleasant physical reaction and emotion consisting usually of rhythmical, usually audible contractions of the diaphragm and other parts of the respiratory system. It is a response to certain external or internal stimuli. Laughter can rise from such activities as being tickled, or from humorous stories, imagery, videos or thoughts. Most commonly, it is considered an auditory expression of a number of positive emotional states, such as joy, mirth, happiness or relief. On some occasions, however, it may be caused by contrary emotional states such as embarrassment, surprise, or confusion such as nervous laughter or courtesy laugh. Age, gender, education, language and culture are all indicators as to whether a person will experience laughter in a given situation. Other than humans, some other species of primate (chimpanzees, gorillas and orangutans) show laughter-like vocalizations in response to physical contact such as wrestling, play chasing or tickling.

Laughter is a part of human behavior regulated by the brain, helping humans clarify their intentions in social interaction and providing an emotional context to conversations. Laughter is used as a signal for being part of a group—it signals acceptance and positive interactions with others. Laughter is sometimes seen as contagious and the laughter of one person can itself provoke laughter from others as a positive feedback.

The genus Pan consists of two extant species: the bonobo and the chimpanzee. Taxonomically, these two ape species are collectively termed panins; however, both species are more commonly referred to collectively using the generalized term chimpanzees, or chimps. Together with humans, gorillas, and orangutans, they are part of the family Hominidae (the great apes, or hominids). Native to sub-Saharan Africa, chimpanzees and bonobos are currently both found in the Congo jungle, while only the chimpanzee is also found further north in West Africa. Both species are listed as endangered on the IUCN Red List of Threatened Species, and in 2017 the Convention on Migratory Species selected the chimpanzee for special protection.

Tool use by non-humans is a phenomenon in which a non-human animal uses any kind of tool in order to achieve a goal such as acquiring food and water, grooming, combat, defence, communication, recreation or construction. Originally thought to be a skill possessed only by humans, some tool use requires a sophisticated level of cognition. There is considerable discussion about the definition of what constitutes a tool and therefore which behaviours can be considered true examples of tool use. A wide range of animals, including mammals, birds, fish, cephalopods, and insects, are considered to use tools.

Primates are well known for using tools for hunting or gathering food and water, cover for rain, and self-defence. Chimpanzees have often been the object of study in regard to their usage of tools, most famously by Jane Goodall, since these animals are frequently kept in captivity and are closely related to humans. Wild tool use in other primates, especially among apes and monkeys, is considered relatively common, though its full extent remains poorly documented, as many primates in the wild are mainly only observed distantly or briefly when in their natural environments and living without human influence. Some novel tool-use by primates may arise in a localised or isolated manner within certain unique primate cultures, being transmitted and practised among socially connected primates through cultural learning. Many famous researchers, such as Charles Darwin in his 1871 book The Descent of Man, have mentioned tool use in monkeys (such as baboons).

Homo sapiens is a distinct species of the hominid family of primates, which also includes all the great apes. Over their evolutionary history, humans gradually developed traits such as bipedalism, dexterity, and complex language, as well as interbreeding with other hominins (a tribe of the African hominid subfamily), indicating that human evolution was not linear but weblike. The study of the origins of humans involves several scientific disciplines, including physical and evolutionary anthropology, paleontology, and genetics; the field is also known by the terms anthropogeny, anthropogenesis, and anthropogony—with the latter two sometimes used to refer to the related subject of hominization.

Primates diverged from other mammals about 85 million years ago (mya), in the Late Cretaceous period, with their earliest fossils appearing over 55 mya, during the Paleocene. Primates produced successive clades leading to the ape superfamily, which gave rise to the hominid and the gibbon families; these diverged some 15–20 mya. African and Asian hominids (including orangutans) diverged about 14 mya. Hominins (including the Australopithecine and Panina subtribes) parted from the Gorillini tribe between 8 and 9 mya; Australopithecine (including the extinct biped ancestors of humans) separated from the Pan genus (containing chimpanzees and bonobos) 4–7 mya. The Homo genus is evidenced by the appearance of H. habilis over 2 mya, while anatomically modern humans emerged in Africa approximately 300,000 years ago.

A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints extremely similar to human fingerprints) are often described as having "hands" instead of paws on their front limbs. The raccoon is usually described as having "hands" though opposable thumbs are lacking.

Some evolutionary anatomists use the term hand to refer to the appendage of digits on the forelimb more generally—for example, in the context of whether the three digits of the bird hand involved the same homologous loss of two digits as in the dinosaur hand.