The largest primates, they have dense and muscular bodies. Their arms are long relative to
their legs. Their arm-span can be more than 96 inches. Their coat is wiry and varies in color with various shades of brown, black, red and gray. Dentition is the same as man.
As males enter adulthood, around 15 years old, they develop a broad, silvery-white saddle along the back, extending over the rump and thigh as they age. At that point, therefore, the male is called a "silverback". Hair length varies over different parts of the body. Hair on the chest is sparse-to-absent, as is the hair on the center of the face, fingers, toes, and underside of the hands and feet. Their skin is jet black almost from birth.
Compared with the female, the male develops more pronounced jaw muscles that attach to the top of his skull, called the "sagittal crest". The brow bone is pronounced, the ears small and the nostrils are splayed and heavily padded. Females achieve their full size around age 10. Infants born in human care weigh
3.5 to 5.5 pounds at birth (usually smaller in the wild) and are weaned in two to four years.
On a scale from 0 being extinct to 10 being common, this animal is ranked: