What is the common name of the baboon species with a reddish-brown face and a mane?

The baboon species with a reddish-brown face and a mane is the Hamadryas baboon. Its scientific name is Papio hamadryas, and it is also called the sacred baboon because of its importance in ancient Egyptian religion.

Adult males develop a striking silver-white mane and mantle, usually becoming fully pronounced at about 10 years old. Females lack the mane and are generally brown, with faces ranging from reddish to dark brown. This strong difference between the sexes is an example of sexual dimorphism.

Hamadryas baboons live in the Horn of Africa and parts of the southwestern Arabian Peninsula, including Ethiopia, Eritrea, Djibouti, Somalia, Saudi Arabia, and Yemen. They organize themselves into small family units that combine into larger bands, a social system that differs from that of many other baboons.

A common mix-up is assuming every maned baboon is a Hamadryas. Olive and Guinea baboons can also show mane-like hair, but the Hamadryas is especially recognizable for its large silver mantle and distinctive social structure.