I am hoping Spike will pipe up shortly.
Geography will be the first method of distinguishing them. (In all seriousness.)
Rowland Ward differentiates three categories: (note the facial markings)
Typical
Royal Sable
East African
Sorry, no image.
SCI has three categories of consequence:
Common Sable
DESCRIPTION Larger than the other subspecies of sable. Adult males are glossy black, with a face that is largely white except for a wide black blaze from forehead to nose and a black stripe from eye to muzzle. Adult females south of the Zambezi River also turn blackish, though they tend to be lighter than males. Females north of the Zambezi tend to be reddish brown rather than black.
DISTRIBUTION Southeastern Angola; Zambia except in the far west; southeastern Katanga Province in Congo (K); Malawi; western and central Tanzania; Mozambique; the Caprivi Strip in Namibia; northern Botswana, Zimbabwe, and the northern Transvaal in South Africa.
TAXONOMIC NOTES Includes
niger (the so-called black sable from south of the Zambezi River) and
kirki (north of the Zambezi and west of the range of the Roosevelt sable). The name
niger Harris, 1838 has priority.
Giant Sable (AKA Royal Sable)
DESCRIPTION Despite its name, this subspecies is actually a little smaller in body than the common sable; however, it has much larger horns that are often widely spread at the tips. Pickup horns nearly 65 inches (165 cm) long have been recorded, with tip-to-tip spreads of as much as 35 inches (89 cm). The male has the same glossy black coat as the typical sable, but its face differs by being mostly black, lacking the white stripe. The female is a bright chestnut red, and is rather similar in appearance to the female Roosevelt sable.
DISTRIBUTION Only in north central Angola in a limited area between the Cuanza and Luando rivers, mainly in and around the Luando reserve and Kangandala National Park.
STATUS Listed as endangered by the IUCN and the USF&WS (1976) and on Appendix I of CITES (1975). Protected under law in Angola. In 1970, the population was estimated at 2,000-3,000. In 1997, a ground survey of part of its range found that it had survived Angola's long civil war in relatively good numbers.
Roosevelt Sable
Hippotragus niger roosevelti
Sable de Roosevelt (Sp). Named after explorer and hunter Kermit Roosevelt, son of former U.S. President Theodore Roosevelt. Sometimes called
East African sable, which is inappropriate, because the common sable has an equally extensive distribution in East Africa. Formerly called
Shimba sable, for the Shimba Hills in Kenya, where it was first described for science by Edmund Heller on the Roosevelts' 1909-1910 East African safari, but this name is no longer suitable (
please see text below).
DESCRIPTION Slightly smaller, lighter in color and with shorter horns than the common sable. Males vary from seal brown in the Shimba Hills to reddish black in the Selous and Kilombero. Females are a bright rufous.
DISTRIBUTION From the Shimba Hills near the southeastern coast of Kenya, southward discontinuously in coastal Tanzania east of longitude 38°E to the Selous Reserve in southern Tanzania; throughout the Selous Reserve; in the Kilombero Valley to the west of the Selous; and south and southeast of the Selous; and south to the Ruvuma River along the Tanzania - Mozambique border. Sable specie below the Ruvuma River have shown evidence of hybridisation.
STATUS The Shimba Hills population of about 120 animals is legally protected. So are the small, scattered populations along the Tanzania coast, though they suffer from local poaching. But a 1998 aerial survey counted 3,900 sable in the Selous and another 6,700 outside it, particularly to the southeast, so roosevelti can no longer be considered endangered.
TAXONOMIC NOTES In previous editions, we followed prevailing scientific opinion in limiting
roosevelti to the small, endangered Shimba Hills population, which we called the Shimba sable. Although Roosevelt and Heller believed the subspecies extended from the Shimba Hills southward along the coast to the Kigani River opposite Zanzibar Island, later authorities limited it to the Shimba Hills. Recent DNA testing has not only shown that Roosevelt and Heller were correct, but also that
roosevelti is found throughout the Selous Reserve and in adjoining areas to the west and south. What remains to be done is to establish its western and southern boundaries through ongoing DNA testing.
REMARKS Hunting of
roosevelti will probably be limited to the Selous Reserve until the western and southern distribution limits are determined. The sable of the Selous have been hunted under a quota of about 70-80 a year, and this is expected to continue. All sable already in the Record Book from the Selous have been reclassified as Roosevelt sable. All new sable entries from the Selous will be recorded as Roosevelt sable.