The male lion's mane is the most recognisable feature of the species.

Accounts of a few individuals that were larger than average exist from Africa and India.

The size and weight of adult lions vary across its range and habitats.

Among felids, the lion is second only to the tiger in size.

The skeletal muscles of the lion make up 58.8% of its body weight and represent the highest percentage of muscles among mammals.

Due to the amount of skull variation in the two species, usually only the structure of the lower jaw can be used as a reliable indicator of species.

Its skull is very similar to that of the tiger, although the frontal region is usually more depressed and flattened and has a slightly shorter postorbital region and broader nasal openings than those of the tiger.

It is readily identifiable at the age of seven months.

The tuft is absent at birth and develops at around 5+1⁄2 months of age. 

The functions of the spur are unknown.