[3] They live in valley forests and on mountain slopes, but are mostly ground-dwelling, which makes them susceptible to hunting and poaching.

[1] The Sanje mangabey is a medium-sized monkey; the sexes are similar in appearance but males are slightly larger than females.

[5] This mangabey is endemic to East Africa, and only occurs in two forests in the Udzungwa Mountains of south-central Tanzania.

It frequents forested valley bottoms near watercourses, and also dry, more open slopes with scattered trees, bracken and Rubus species.

[5] The Sanje mangabey is a diurnal species and spends around half its time on the ground, and the rest foraging in the upper and middle canopy, and the understory.

Troops of mangabeys occupy a home range, and spend the night in one of about eight clumps of tall trees that are habitually used for sleeping.

Figs, the stones of Parinari excelsa and other large or hard items are often stored in cheek pouches, being cracked open later with the help of strong premolar teeth.