The lion (Panthera leo) is a species (Opens in a new window) in the family Felidae (Opens in a new window) and a member of the genus (Opens in a new window) Panthera (Opens in a new window). It has a muscular, deep-chested body, short, rounded head, round ears, and a hairy tuft at the end of its tail. It is sexually dimorphic (Opens in a new window); adult male lions have a prominent mane. With a typical head-to-body length of 184–208 cm (72–82 in) they are larger than females at 160–184 cm (63–72 in). It is a social species (Opens in a new window), forming groups called prides. A lion pride consists of a few adult males, related females and cubs. Groups of female lions usually hunt together, preying mostly on large ungulates (Opens in a new window). The lion is an apex (Opens in a new window) and keystone predator (Opens in a new window); although some lions scavenge when opportunities occur and have been known to hunt humans, the species typically does not.

Typically, the lion inhabits grasslands (Opens in a new window) and savannas (Opens in a new window), but is absent in dense forests (Opens in a new window). It is usually more diurnal (Opens in a new window) than other big cats, but when persecuted it adapts to being active at night (Opens in a new window) and at twilight (Opens in a new window). During the Neolithic (Opens in a new window) period, the lion ranged throughout Africa (Opens in a new window), Southeast Europe (Opens in a new window), and Western (Opens in a new window) and South Asia (Opens in a new window)but today it has been reduced to fragmented populations in sub-Saharan Africa (Opens in a new window) and one critically endangered population in western India. It has been listed as Vulnerable (Opens in a new window) on the IUCN Red List (Opens in a new window) since 1996 because populations in African countries have declined by about 43% since the early 1990s. Lion populations are untenable outside designated protected areas. Although the cause of the decline is not fully understood, habitat loss (Opens in a new window) and conflicts with humans are the greatest causes for concern.

One of the most widely recognised animal symbols in human culture, the lion has been extensively depicted in sculptures and paintings, on national flags, and in contemporary films and literature. Lions have been kept in menageries (Opens in a new window) since the time of the Roman Empire (Opens in a new window) and have been a key species sought for exhibition in zoological gardens (Opens in a new window) across the world since the late 18th century. Cultural depictions of lions (Opens in a new window) were prominent in Ancient Egypt (Opens in a new window), and depictions have occurred in virtually all ancient and medieval cultures in the lion's former and current ranges.