The lion (Panthera leo) is a species (Öffnet in neuem Fenster) in the family Felidae (Öffnet in neuem Fenster) and a member of the genus (Öffnet in neuem Fenster) Panthera (Öffnet in neuem Fenster). 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 (Öffnet in neuem Fenster); 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 (Öffnet in neuem Fenster), 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 (Öffnet in neuem Fenster). The lion is an apex (Öffnet in neuem Fenster) and keystone predator (Öffnet in neuem Fenster); although some lions scavenge when opportunities occur and have been known to hunt humans, the species typically does not.

Typically, the lion inhabits grasslands (Öffnet in neuem Fenster) and savannas (Öffnet in neuem Fenster), but is absent in dense forests (Öffnet in neuem Fenster). It is usually more diurnal (Öffnet in neuem Fenster) than other big cats, but when persecuted it adapts to being active at night (Öffnet in neuem Fenster) and at twilight (Öffnet in neuem Fenster). During the Neolithic (Öffnet in neuem Fenster) period, the lion ranged throughout Africa (Öffnet in neuem Fenster), Southeast Europe (Öffnet in neuem Fenster), and Western (Öffnet in neuem Fenster) and South Asia (Öffnet in neuem Fenster)but today it has been reduced to fragmented populations in sub-Saharan Africa (Öffnet in neuem Fenster) and one critically endangered population in western India. It has been listed as Vulnerable (Öffnet in neuem Fenster) on the IUCN Red List (Öffnet in neuem Fenster) 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 (Öffnet in neuem Fenster) 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 (Öffnet in neuem Fenster) since the time of the Roman Empire (Öffnet in neuem Fenster) and have been a key species sought for exhibition in zoological gardens (Öffnet in neuem Fenster) across the world since the late 18th century. Cultural depictions of lions (Öffnet in neuem Fenster) were prominent in Ancient Egypt (Öffnet in neuem Fenster), and depictions have occurred in virtually all ancient and medieval cultures in the lion's former and current ranges.