The lion is one of four "big cats" in the genus Panthera. Reaching up to over 272 kg (600 lb), it is the second-largest cat after the tiger. They currently exist in the wild in sub-Saharan Africa and in Asia with a critically endangered remnant population in northwest India, having disappeared from North Africa, the Middle East and western Asia in historic times.

Lions live for approximately 10–14 years in the wild, while in captivity they can live over 20 years. They typically inhabit savanna and grassland, although they may take to bush and forest. Lions are unusually social compared to other cats. A lion pride consists of related females and offspring and a small number of dominant males. Groups of female lions typically hunt together, preying mostly on large ungulates. The lion is an apex and keystone predator, though will resort to scavenging if the opportunity arises. While lions, in general, do not selectively hunt humans, some have been known to become man-eaters and seek human prey.

The lion is a vulnerable species, having seen a possibly irreversible population decline of 30 to 50% over the past two decades in its African range;[1] populations are untenable outside designated reserves and national parks. Although the cause of the decline is not well-understood, habitat loss and conflicts with humans are currently the greatest causes of concern.