Which big cat species has a mane in adult males?

The big cat species whose adult males have a mane is the lion.

The lion, Panthera leo, is the only living big-cat species in which adult males typically grow a prominent mane. It develops during adolescence as testosterone levels rise and can extend over the head, neck, shoulders and chest. Mane color and size vary with age, genetics, health and climate.

A mane may signal a male’s condition to potential mates. Darker, fuller manes have been associated with greater reproductive success in some studies, although a heavy mane can also increase heat stress. The mane may offer some protection during fights, but that explanation remains debated. Not every male has a large mane: lions in hot regions, including parts of Tsavo, may be nearly maneless.

Lionesses usually lack manes, though rare maned lionesses have been reported, possibly because of increased testosterone. The feature also helps distinguish lions from tigers, leopards and jaguars, none of which naturally develop a comparable adult-male mane.