Collared brown lemur can be distinguished according to sexes based on the colors of their dorsal coat, ventral coat, tail, face and head, cheeks, and eyes.
The following table illustrates the coloration differences between the sexes: Brownish-gray Browner and more rufous than the male's Paler gray Pale creamy-gray Darker gray with a dark stripe along the spine Same as dorsal coat Muzzle, face, and crown are dark gray to black; creamy to gray-colored eyebrow patches vary between individuals Gray, with faint gray stripe extending over crown Creamy to rufous-brown cheeks and beard are thick and bushy Rufous-brown, but less prominent than the male's orange-red orange-red 
