The Gelada Baboon

The Gelada Baboon, often just called Gelada, is a species of Old World monkey, with the genus name of Theropihtecus. They are found only in the Ethiopian highlands, though scientists have discovered their fossils in other places in Africa, Asia, and along the Mediterranean. There are only 50,000 to 60,000 Geladas known to exist, however, they are not listed as endangered creatures.

Geladas are not really baboons, since their nostrils are set in a different place from true ones and they have a bright patch of skin on their chests, but many people classify them as baboons anyway. Geladas have a lifespan of more than 19 years, and can get up to 74 cm tall, and weigh up to 20 kg. They live on treeless cliffs, in order to be safe from predators, and live in packs of up to 600. They are herbivores that mainly eat grass. They have the most opposable thumb of all primates, excluding humans, which helps them in their grass picking.

Thanks to
http://www.bbc.co.uk/nature/wildfacts/factfiles/233.shtml
and
http://en.wikipedia.org/wiki/Gelada