This species is completely black. Animals differ from other completely black gibbons by their smaller size and the absence of an external throat sac (as compared to S. syndactylus) and by the absence of an occipital crest (as compared to males of N. concolor or N. sp. cf. nasutus).
|Adult male "Bilou", Twycross Zoo, England, 4 Oct. 1988.||Same adult male "Bilou", Twycross Zoo, England,
Jan. 2005 (photograph by Melissa Waller).
This male appears to have developped a brownish tinge, more fluffy fur and a broader hairdo, as compared to the photograph on the left made almost 20 years earlier.
|Adult female "Sunny", Taman Safari Zoo, Cisarua, Indonesia, 16 Sept. 1998.||Adult female, Jakarta Zoo, Indonesia, 15 May 2005 (photograph by Sally Keith).|
|Male, pet, Siberut Island, Indonesia, 15 July 2005 (photograph by Sally Keith).||Same male, pet, Siberut Island, Indonesia, 15 July 2005 (photograph by Melissa Waller).|
|Infant pet, Pokai, a small village near Muara Sikabaluan, northern Siberut Island, Indonesia, 27 September 2003 (photograph by Danielle J. Whittaker).|