Biology
Vitruvian man by Leonardo da Vinci
Morphology
Humans can be distinguished from other living apes by a strikingly enlarged brain, reduced hair coverage on most parts of the body, and by a suite of skeletal and muscular adaptations associated with habitual bipedal locomotion, including the loss of the grasping ability of the foot. Humans are terrestrial bipeds with a limited ability to swim and dive that must be learned.
The species shows strong variation in body size and proportions, and pigmentation, some of which can be related to the wide range of environments in which Homo sapiens lives. Humans exhibit moderate sexual dimorphism in body size.
Nutrition
Humans are opportunistic omnivores, showing remarkable ingenuity in extracting, producing, processing and preserving foods. Humans are the only species that can control or make fire, and cooking is practiced by all known extant human groups.
Regional variations in diet are influenced by availability within a particular environment, by cultural traditions such as food preferences and avoidances, and even genetic factors. Lactase persistence, which allows some people to consume milk and dairy products throughout life, is a recent adaptation to dairy consumption that would only have been useful among populations with a tradition of dairy farming.
Life cycle
Human social structure is highly variable. Traditional arrangements that may be formalised through marriage include monogamous pairs as well as one-male multi female groups and, more rarely, one-female multi-male groups.
Both males and females may disperse from their natal community. Human infants are born in a relatively immature state and remain dependent on adult carers for several years.
Inter birth intervals are relatively short such that females may have multiple dependent offspring at different stages of developmental maturity. Other members of a community or extended family network may contribute to the care of dependent children, including fathers, older siblings and grandparents.
Humans are typically diurnal and sleep in temporary or permanent shelters at night. Family groups often have exclusive use of a shared sleeping space or residence that may serve as a home base for extensive periods.
