Arctocebus calabarensis (J. A. Smith, 1860)

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Lorisidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 210-220 : 211

1.

Calabar Angwantibo

Arctocebus calabarensis

French: Potto de Calabar / German: Barenmaki / Spanish: Poto dorado de Calabar

Other common names: Angwantibo, Golden Potto of Calabar

Taxonomy. Perodicticus calabarensis J. A. Smith, 1860 ,

Nigeria, Old Calabar.

“Angwantibo” is the name ofthis primate in the Ibibio language from southern Nigeria. The Golden Potto ( A. aureus ) was formerly considered to be a subspecies. Monotypic.

Distribution. W Central Africa, from SW Cameroon (E Niger River) to S Nigeria (Sanaga River).

Descriptive notes. Head-body 26-35 cm, tail 1 cm; weight 230-465 g. Small and woolly with a vestigial tail that can be mistaken as testes and confuses identification ofsexes at night. Sexes alike in size and color and are difficult to tell apart from a distance; yellow-brown above, with a whitish or grayish underside. The muzzle is pointed, and no facial markings are evident. Ears are small and rounded. There is a white line on the face from the brow to the nose. Second and third digits of the hand are greatly reduced. Infants are woollier and more muted in color but otherwise resemble adults.

Habitat. Primary and secondary lowland rainforest, high deciduous forest, and derived savanna zone, where they are most typicalin tree-fall zones. The Calabar Angwantibois sometimes found on farmland edges and plantations. Individuals spend much of their time in the tangle shrub layer and are able to use very small branches, vines, and lianas; they are usually encountered below 3 m above the ground.

Food and Feeding. The Calabar Angwantibo seems to be primarily insectivorous. Diet is mainly known from analyses of stomach contents; insects (mostly caterpillars and beetles) make up the bulk ofthe diet, but snails, lizards, and fruits are also eaten. Recently captured angwantibos have eaten orthopterans, mantids, beetles, and snails.

Breeding. Births occur throughout the year, but they are more common between January and April. The estrous cycle is 36-45 days. Gestation is 130-133 days, producing one offspring of about 35 g, which is weaned at 3-5 months. Minimum interbirth interval is 4-5 months, meaning that two young can be produced in one year—a very different system from the Asian lorises. Sexual maturity occurs at 9-10 months. Young are carried on the mother’s fur or parked while she forages. Longevity in captivity 1s c.13 years.

Activity patterns. Calabar Angwantibos are arboreal and nocturnal, and they can be seen throughout the night, almost always alone. They move in a continuous and slow fashion using small branches on which they can maintain a grip with their shortened digits. They travel on the ground when they have to. Rapid movement is possible when threatened, but they also adopt a defense posture. An angwantibo will hunch its back and tuck its head between its arms. It will then thrust its back toward a predator with mouth open, confounding the predator that cannot detect which end is the head. In this way, the angwantibo can bite the predator from beneath its armpit.

Movements, Home range and Social organization. The Calabar Angwantibo has a steady non-leaping locomotion and relies on continuous supports. No study has yet been undertaken ofthe species’ home range or social organization. The Calabar Angwantibo was mainly solitary and did not appear to vocalize in the Rhoko Forest, adjacent to Cross River National Park in south-eastern Nigeria. Adult males fight if placed together in captivity. The Calabar Angwantibosleeps by day in an upright position in dense vegetation where it is protected from sun, wind, rain, and predators.

Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List. The Calabar Angwantibo is sometimes hunted for food in Nigeria. Broadscale forest clearing for plantations, agriculture, and wood products negatively affect the Calabar Angwantibo, but it can use secondary forests if sufficient undergrowth for movement and safety remains. It is known to occur in four protected areas: Korup National Park in Cameroon and Cross River National Park, Akpaka Forest Reserve, and MamuRiver Forest Reserve in Nigeria. It also occurs in the proposed Mount Kupe Forest Reserve in Cameroon.

Bibliography. Bearder & Honess (1992), Charles-Dominique (1966), Groves (2001), Hill (1953d), Hill & Meester (1971), Jenkins (1987), Jewell & Oates (1969a, 1969b), Jones (1982), Kingdon (1997), Manley (1974), Montagna et al. (1966), Oates & Jewell (1967), Pimley (2009), Rode (1947), Sanderson (1940), Schein (2008), Schwartz & Beutel (1995), Schwarz (1931b).

Figures

On following pages: 7. Red Slender Loris (Loris tardigradus); 8. Bengal Slow Loris (Nycticebus bengalensis); 9. Sunda Slow Loris (Nycticebus coucang); 10. Javan Slow Loris (Nycticebus javanicus); 11. Bornean Slow Loris (Nycticebus menagensis); 12. Pygmy Slow Loris (Nycticebus pygmaeus).

Distribution. W Central Africa, from SW Cameroon (E Niger River) to S Nigeria (Sanaga River).