In the wild, the hamadryas baboon is omnivorous; however the majority of its diet consists of plant matter. Hamadryas baboons in Africa and Arabia share a similar diet to some extent: both populations primarily eat grass seeds, roots, berries, and the flowers, leaves, and pods of acacia trees.

Baboon populations in Arabia commonly eat cactus fruit and palm nuts, as well. Non-plant food sources make up a small portion of their diet and include bird eggs, carrion, small mammals, and occasionally insects like locusts.

Females give birth to one baby at a time. For the first 3 weeks of its life, a baby will hold onto its mother by gripping her hair as she moves around. Hamadryas baboon babies have pink skin and black hair until they are one year old, at which point their hair turns brown and resembles that of the adults.

Hamadryas baboons live in diverse habitats ranging from subdesert to savanna and into steppe, plains, and arid brushland.