▁with ▁white ▁on ▁the ▁upper ▁surface ▁and ▁is ▁all ▁white ▁on ▁the ▁unders ide . ▁The ▁sides ▁are ▁distinguish able ▁from ▁other ▁species ▁in ▁that ▁they ▁are ▁pure ▁white , ▁the ▁source ▁of ▁their ▁name . ▁The ▁r ump ▁and ▁th igh s ▁are ▁also ▁white ▁and ▁l ined ▁with ▁a ▁few ▁black ▁hair s . ▁A ▁median ▁black ▁line ▁conce aled ▁by ▁so oty , ▁brown ish , ▁and ▁white - ti pped ▁hair s ▁div ides ▁the ▁r ump . ▁The ▁lim bs ▁are ▁white , ▁but ▁their ▁outer ▁surfaces ▁are ▁st ained ▁a ▁buff ▁color . ▁The ▁g ular ▁p ouch ▁is ▁also ▁buff y ▁while ▁the ▁sides ▁of ▁the ▁neck ▁and ▁shoulders ▁become ▁more ▁och race ous ▁in ▁color . ▁The ▁head ▁is ▁a ▁cre am ▁buff ▁color , ▁mixed ▁with ▁black , ▁with ▁wh it ish ▁areas ▁around ▁the ▁sides ▁of ▁the ▁eyes . ▁The ▁ears ▁are ▁covered ▁with ▁short ▁yellow ish - b rown ▁hair s ▁that ▁are ▁mixed ▁with ▁black ▁anterior ly ▁and ▁white ▁posterior ly . ▁The ▁a pe x ▁of ▁the ▁ear ▁is ▁white - ti pped . ▁Below ▁the ▁a pe x ▁of ▁the ▁ear ▁is ▁a ▁tu ft ▁of ▁black ▁hair . ▁The ▁long ▁fr ing es ▁on ▁the ▁anterior ▁edge ▁of ▁the ▁ear ▁are ▁och race ous ▁buff , ▁while ▁the ▁fr ing es ▁of ▁the ▁tip ▁of ▁the ▁ear ▁and ▁posterior ▁edge ▁are ▁white . ▁The ▁inner ▁surface ▁of ▁the ▁ear ▁is ▁almost ▁bare ▁except ▁for ▁a ▁dus ky ▁spot