Cercocebus galeritus, Peters, 1879

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 550-755 : 651

23.

Tana River Mangabey

Cercocebus galeritus

French: Mangabey de la Tana / German: Tana-Mangabe / Spanish: Mangabey del Tana

Other common names: Tana Mangabey, Tana River Crested Mangabey

Taxonomy. Cercocebus galeritus Peters, 1879 ,

Kenya, Tana River, Mitole (2° 10’ S, 40° 10’ E).

Some experts have included the taxa C. aghs and C. sanjei as subspecies of C. galeritus , while others give these taxa full species status. C. galeritus is broadly sympatric with Piliocolobus rufomitratus and Cercopithecus mitis albotorquatus; narrowly sympatric on the forest edges with Papio cynocephalus and Chlorocebus pygerythrus . Monotypic.

Distribution. SE Kenya, endemic to riparian forest patches along the lower Tana River; an additional small population was recently discovered in the Tana River Delta.

Descriptive notes. There are no specific measurements available. In his 1997 Field Guide to African Mammals, J. Kingdon provided the following estimates: head—body c.50-63 cm (males) and c.42-53 cm (females), tail ¢.45-77 cm; weight ¢.8-10 kg (males) and ¢.5.6-5 kg (females). The adult male type specimen, as measured by W. Peters, had a head-body length of 49 cm and a tail length of 72 cm. Fur of the Tana River Mangabeyis long, loose, and wavy, being a somewhat inconspicuously speckled grayish-yellow or mushroom color above, with fluffy-haired, yellowish-white underparts. Limbs are not speckled, and forearms, hands, and feet are dark brown. Tail has a slight, pale tuft, particularly in adult males. Face and ears are black, cheeks and temples are whitish, and eyelids are bright white. There is a center parting on the crown, beginning immediately behind the forehead, with very long, darker hairs diverging from it on either side. These hairs become even longer back toward the middle of the crown. Male Tana River Mangabeys call with a “whoop-rumble,” which is typical of mangabey species. Adult females are smaller than males.

Habitat. Dry riparian gallery forests and adjacent patches of bush along the Tana River. The Tana River Mangabey is highly dependent on old growth forest. January and February are the hottest and driest months. Annual rainfall is 500-600 mm and is distributed bimodally: March—June (peaks in March-April) and October-December (peaks in November-December). The Tana River often changesits course, resulting in ox-bow lakes that have forest patches around them that are occupied by mangabey groups. Gallery forest depends on ground water. Changes in river course affect forest dynamics—patches along the old river bed dry up while new patches are established along new river courses. Sometimesthe forest is flooded for extended periods (canopy trees may die and fall), resulting in open patches in the canopy. As such, forests used by the Tana River Mangabey are characterized by a mosaic of habitats in different stages of succession.

Food and Feeding. Tana River Mangabeys mainly eat fruits, especially figs, and hard nuts and seeds, with some leaves, flowers, and animal prey (including invertebrates and small vertebrates such as frogs and lizards). They spend ¢.73% of their feeding time on the ground or in the undergrowth (0-2 m high). At other times,they feed in trees up to and over 20 m high. During food scarcity (dry season), they spend more time foraging and travel farther.

Breeding. Female Tana River Mangabeys most likely have a 30day reproductive cycle. A single young is born after a gestation of 180 days. As in other mangabey species, females often exhibit post-conception swellings. Individuals may live up to 20 years. Birth season is in November—February. The interbirth interval is two years.

Activity patterns. Tana River Mangabeys are diurnal, terrestrial, and arboreal.

Movements, Home range and Social organization. The average size of a group home range of the Tana River Mangabey is ¢.47 ha. The average daily movement is 1500 m (range 1000-2600 m). Tana River Mangabeys live in multimale-multifemale groups, averaging 27 individuals (range 6-62). Groups may have up to six adult males. Larger groups may be fusions of smaller units. The population density is less than 0-07 ind/km?.

Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. The Tana River Mangabeyis listed as Class A in the African Convention on the Conservation of Nature and Natural Resources. It survives as a single population in an extremely small area, confined to a 60km-long narrow strip of fragmented gallery forests. In 1976, the 175km? Tana River National Primate Reserve was established to protect the Tana River Mangabey and the equally threatened Tana River Red Colobus ( Piliocolobus rufomitratus ). This reserve harbors ¢.56% of the extant groups of Tana River Mangabeys. Of the 44% living outside of reserve, 10% live in forests under management of the Tana Delta Irrigation Project, while the remainder is on Trust/Government land. Damming and irrigation cause changes to the natural flood regime of the Tana River and result in vegetation change and the loss of gallery forests. Forest clearing, habitat degradation, and fires are serious threats. The Tana River Mangabey (and the Tana River Red Colobus ) depends on old growth forest, which is now found only in few and isolated fragments because of their constant destruction by humans (e.g. clearing for agriculture, dyke construction, burning, extraction of honey, building materials, and firewood). Manyfruiting trees important to Tana River Mangabeys are cut to make canoes and for building. A favored source of fruits—the palm, Phoenix reclinata ( Arecaceae )—is cut to make palm wine. In 2008, the total population of Tana River Mangabeys was estimated at ¢.1200 individuals. In 2001, 2070 individuals were counted in 59 groups. The Tana River Mangabey needs to be closely monitored given the insecurity of its remaining habitat and potential future threats.

Bibliography. Bentley-Condit (2009), Butynski & Mwangi (1994), Daegling & McGraw (2007), Decker & Kinnaird (1992), Groves (1978, 2001, 2005b), Groves et al. (1974), Grubb (2006), Grubb et al. (2003), Gust (1994a), Hill (1974), Homewood (1975, 1976, 1978), Homewood & Mkunga (1977), Jolly (2007), Karere et al. (2004), Kingdon (1997), Kinnaird (1990a, 1990b), Kinnaird & O'Brien (1991, 1993/1994, 2000), Mbora & McPeek (2010), Mbora et al. (2009), McGraw & Fleagle (2006), Medley (1990, 1993), Moinde-Fockler et al. (2007), Muoria et al. (2003), Smith & Jungers (1997), Swedell (2011), Wahungu (1998, 2001), Wahungu et al. (2005), Waser (1982), Waser & Homewood (1979), Wieczkowski (2004, 2005a, 2005b, 2009, 2010), Wieczkowski & Kinnaird (2008), Wieczkowski & Mbora (1999/2000).

Figures

23. Tana River Mangabey (Cercocebus galeritus), 24. Agile Mangabey (Cercocebus agilis), 25. Golden-bellied Mangabey (Cercocebus chrysogaster), 26. Sanje River Mangabey (Cercocebus sanjer), 27. Sooty Mangabey (Cercocebus atys), 28. White-naped Mangabey (Cercocebus lunulatus), 29. Red-capped Mangabey (Cercocebus torquatus), 30. Mandrill (Mandnrillus sphinx), 31. Drill (Mandrillus leucophaeus), 32. Gray-cheeked Mangabey (Lophocebus albigena), 33. Rusty-mantled Mangabey (Lophocebus osmani), 34. Johnston's Mangabey (Lophocebus johnstoni), 35. Ugandan Crested Mangabey (Lophocebus ugandae), 36. Northern Black Crested Mangabey (Lophocebus aterrimus), 37. Southern Black Crested Mangabey (Lophocebus opdenboschi), 38. Kipunji (Rungwecebus kipunji)

Distribution. SE Kenya, endemic to riparian forest patches along the lower Tana River; an additional small population was recently discovered in the Tana River Delta.