Hydrictis maculicollis

33. Spotted-necked Otter Hydrictis maculicollis French: Loutre a cou tacheté / German: Fleckenhals-Otter / Spanish: Nutria moteada Taxonomy. Lutra maculicollis Lichtenstein, 1835, Cape Province, South Africa. The Spotted-necked Otter was previously included in the genus Lutra by some authors, but recent molecular studies have shown that its inclusion in Lutra would make this genus paraphyletic. Monotypic. Distribution. Sub-Saharan Africa from Guinea Bissau in the W to SW Ethiopia, E Kenya, and Tanzania in the E, and S to N Namibia, Botswana, and NW Zimbabwe; also Malawi, Mozambique, and E South Africa. Descriptive notes. Head-body 71-76 cm (males), 57-60.5 cm (females), tail 38.5-44 cm (males), 41-44 cm (females); weight 5.7-6 kg (males), 3.8-4.7 kg (females), adult males are larger and heavier than females. The Spotted-necked Otter has a long body, short limbs, and a long tail. The pelage varies from reddish to dark brown. There are creamy-white to white mottled markings on the upper chest and throat. All the feet are fully webbed and there are claws on all the digits. The skull is long and narrow and lightly built, but with a well-developed sagittal crest. Dental formula: 13/3, C1/1,P 4/3, M 1/2 = 36. Habitat. Spotted-necked Otters are found in freshwater rivers, lakes, and swamps with large areas of open water; they are absent from coastal or estuarine areas. They seldom venture more than 10 m away from water and prefer shallow, freshwater areas, where there is continuity of lakeside vegetation, low pollution, and no crocodiles. In KwaZulu-Natal, South Africa, Spotted-necked Otters were most often located in rivers (40% of 706 locations) and near dams (45%), with only occasional use of swamps (3%) and oxbow lakes (2%). Food and Feeding. The diet includesfish (Barbus, Clarias, Haplochromis, Micropterus salmoides, Salmo trutta, and Tilapia), crabs (Potomonautes), and frogs (mostly Xenopus laevis and Rana). Insects and birds are also occasionally eaten. Crabs are the major dietary item during spring, summer, and autumn, whereas fish dominate in winter. Most fish consumed are less than 20 cm in length. In the fish-rich waters of east and central Africa, the diet consists almost entirely of fish, whereas in the fish-poor waters of South Africa, crabs and frogs are consumed in addition to fish. On Lake Victoria, Tanzania, 61% of spraints collected contained 46% Haplochromis, 14% Tilapia, catfish (Bagrus or Clarias), and 1% crab (Potamon niloticus). Direct observations of feeding Spottednecked Otters also revealed a diet dominated by Haplochromis. On Lake Muhazi, Rwanda, 154 spraints contained 80% fish, 10% insects, 3% molluscs, 2% birds and frogs. In Eastern Cape Province, South Africa, the diet is mostly fish (47%), crabs (38%), and frogs (8%). In KwaZulu-Natal, the frequency of occurrence of food items in 516 spraints was 64% fish, 43% crabs, 43% amphibians, and 18% insects. In contrast, 228 spraints collected near a troutriver contained 39% crabs, 38% fish, 20% frogs, 2% insects (mostly dragonfly larvae, Odonata), and unidentified birds. In a non-trout area, 66 spraints contained 30% crabs, 27% frogs, 25% fish, 10% birds (mostly Anatidae and little grebe Tachybaptus ruficollis), and 5% insects. In three stomachs from the Cape Province, South Africa, one contained crabs, one contained frogs and fish, and one contained frogs,fish, a beetle (Coleoptera), and a caterpillar. Spotted-necked Otters generally fish alone and almost all fishing is done within 10 m from the shore. When fishing in groups, cooperation among individuals may help facilitate prey capture by herding fish toward each other. Fishing in groups probably occurs when females are training their young. Fish are captured during short dives of less than 20 seconds. Once underwater, a Spotted-necked Otter scans for prey, turning its head from side to side. Prey are detected visually and pursued until captured. Crabs, fish, and frogs are captured with the mouth; the forefeet are not used in prey capture. Fish smaller than 10 cm are consumed in the water, but larger fish are taken to shore for consumption. Fishing forays typically last 10-20 minutes, but may last up to 3 h. Activity patterns. Mostly diurnal, with activity peaks during early morning and late afternoon. In KwaZulu-Natal, Spotted-necked Otters were most active from 06:00-09:00 h and 15:00-21:00 h. Nocturnal activity usually only occurs during periods of full moon. Rest sites are in rock cavities, bank dens, holes in root systems, or dense vegetation. Spotted-necked Otters can dig their own burrows. In KwaZulu-Natal, resting sites were among trees and shrub roots (29%), reeds (21%), small islands near dams (23%), tall grass (14%), swamps (11%), and sheltered places among rocks (2%). A 4-2-km section of river contained ten resting sites, with a mean distance of 467 m between dens. Movements, Home range and Social organization. Spotted-necked Otters travel mostly in water, swimming underwater and surfacing briefly to breathe. Swimming speed reaches 3—4 km /h. Spotted-necked Otters may be found in small family groups of up to five individuals, although groups of up to 20 animals have been reported. Group size varies according to locality. Of 14 sightings in KwaZulu-Natal, six were singles, three were pairs, three were trios, one was of four, and one offive. In Rwanda, 75% of observations were ofsolitary Spotted-necked Otters; pairs or trios occurred on occasion and usually consisted of a female with young. In Rwanda, maximum group size was eleven and most animals foraged alone. In Lake Victoria, Tanzania, Spotted-necked Otters were most often seen in groups of three and solitary animals were observed on only five occasions; these groups often travelled together, but fed individually. The home ranges of males are larger than those of females. In KwaZulu-Natal, the mean home rangesize for three males was 16- 2 km?, and 5-8 km * for three females. Spotted-necked Otters appeared to be non-territorial as there was large intra- and inter-sexual overlap of home ranges. Population density on Lake Muhazi (3-4 km? in size), Rwanda, was two otters per km of shoreline. In KwaZulu-Natal, density was 0-4-0-6 otters per km of shoreline. Near Kageye, Tanzania, 9-10 otters occupied a 10-km section of the coast of Lake Victoria. In KwaZulu-Natal, the density of otters was estimated at one otter per 6-11 km of river and at one otter per 1-6— 2-4 km of river. Breeding. In Tanzania, mating occurs in July and the young are born in September, after a gestation of c. 60 days. In Zambia, three two-week-old cubs from one litter were captured in December. Delayed implantation probably does not occur. Litter size is one to three. Neonates are blind and helpless. The young remain with the mother for up to one year. Males do not provide parental care. Status and Conservation. CITES Appendix II. Classified as Least Concern in The IUCN Red List. Although this is a widespread species, there are local population declines occurring. Spotted-necked Otters are sensitive to habitat alterations and pollution, and because they consume fish, they are susceptible to bioaccumulation of pesticides and other toxic chemical compounds. Throughout Africa, otters are killed for their skins and meat or because they are regarded as competitors for food, particularly in rural areas where fishing is an important source of income. During the last few years, their habitats have been drastically changed or lost following bush clearance, deforestation, overgrazing, siltation, draining of wetlands, water extraction, or denudation ofriparian vegetation. Bibliography. Angelici et al. (2005), Koepfli & Wayne (1998), Kruuk & Goudswaard (1990), Lariviere (2002b), Lejeune (1989), Mortimer (1963), Perrin & Carugati (2000), Perrin & D’Inzillo (2000), Procter (1963), Roberts (1951), Rowe-Rowe (1977a, 1977b, 1995), Rowe-Rowe & Somers (1998), Skinner & Smithers (1990), Smithers & Chimimba (2005), Somers & Purves (1996), Stuart (1985), Wozencraft (2005).Published as part of Don E. Wilson & Russell A. Mittermeier, 2009, Mustelidae, pp. 564-656 in Handbook of the Mammals of the World – Volume 1 Carnivores, Barcelona :Lynx Edicions on page 644, DOI: 10.5281/zenodo.571404