The lion (Panthera leo) is a species in the family Felidae; it is a muscular, deep-chested cat with a short, rounded head, a reduced neck and round ears, and a hairy tuft at the end of its tail. The lion is sexually dimorphic; males are larger than females with a typical weight range of 150 to 250 kg (330 to 550 lb) for the former and 120 to 182 kg (265 to 400 lb) for the latter. Male lions have a prominent mane, which is the most recognisable feature of the species. A lion pride consists of a few adult males, related females and cubs. Groups of female lions typically hunt together, preying mostly on large ungulates. The species is an apex and keystone predator, although they scavenge when opportunities occur. Some lions have been known to hunt humans, although the species typically does not.
Typically, the lion inhabits grasslands and savannas but is absent in dense forests. It is usually more diurnal than other big cats, but when persecuted it adapts to being active at night and at twilight. In the Pleistocene, the lion ranged throughout Eurasia, Africa and the Americas from the Yukon to Peru but today it has been reduced to fragmented populations in Sub-Saharan Africa and one critically endangered population in western India. It has been listed as Vulnerable on the IUCN Red List 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 and conflicts with humans are the greatest causes for concern.
The lion evolved between 1 million and 800,000 years ago in Africa, from where it spread throughout the Holarctic region. The earliest fossil record in Europe was found near Pakefield in the United Kingdom and is about 680,000 years old. From this lion, the late Pleistocene Eurasian cave lion probably derived about 300,000 years ago. Fossil remains found in the Cromer Forest Bed suggest it was of a gigantic size and represented a lineage that was genetically isolated and highly distinct from lions in Africa and Asia. It was distributed throughout Europe, across Siberia and into western Alaska via the Beringian landmass. The gradual formation of dense forest likely caused the decline of its geographic range near the end of the Late Pleistocene. Lion bones are frequently encountered in cave deposits from Eemian times, suggesting the cave lion survived in the Balkans and Asia Minor. There was probably a continuous population extending into India. Fossil lion remains were found in Pleistocene deposits in West Bengal. It became extinct about 10,000 years ago at the end of the last glacial period without mitochondrial descendants on other continents.