Mandrills live in large groups called hordes that can contain hundreds of individuals - some of the biggest social groups of any primate. Moving through the forest together, they make a tremendous amount of noise as they call to each other, dig for roots and chase each other through the trees.
They eat almost anything the forest offers: fruits, nuts, roots, insects, and sometimes small lizards or frogs. Their cheek pouches - stretchy pockets inside their cheeks - work like lunchboxes. They stuff food in while foraging and then sit safely somewhere else to chew and swallow it properly.
The bright colours of a male mandrill's face are connected to how healthy and strong he is. A very healthy male will have the most vivid blue and red colouring. Females and young mandrills have duller colours but the same intelligent, curious eyes. Mandrills are smart animals and have been observed using tools in the wild.