Lontra longicaudis Gray 1843

30. Neotropical Otter Lontra longicaudis French: Loutre néotropicale / German: Siidamerikanischer Fischotter / Spanish: Nutria neotropical Taxonomy. Lutra longicaudis Olfers, 1818, Brazil. Three subspecies are recognized. Subspecies and Distribution. L. l. longicaudis Olfers, 1818 — Argentina, Bolivia, Ecuador, S Brazil, Paraguay, Peru, and Uruguay. L. l. annectens Major, 1897 — Belize, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Panama, Nicaragua, and Venezuela. L. l. enudris Cuvier, 1823 — NE Brazil, the Guyanas, and Trinidad. Descriptive notes. Head-body 36-66 cm,tail 37-84 cm; weight 5-15 kg, adult males are 20-25% larger than females. The Neotropical Otter is heavily built, with a long body, short limbs, and fully webbed feet. The pelage is dark brown, with a gray neck and throat. The muzzle is broad, with a yellowish white tip and long vibrissae on each side. The skull is heavy, long, and flat. Habitat. Neotropical Otters are found in fast flowing, clear rivers and streams, in both deciduous and evergreen forests, at elevations up to 3000 m. They prefer waterways with clear water, abundant waterside vegetation, and high availability of potential den sites; they are rare or absent from sluggish, murky, lowland waters. In Northern Mexico, along a 30 km stretch ofriver, the habitat preferred by a Neotropical Otter included pools that averaged more than 0-8 m deep, more than 14- 6 m wide, with over 64% understory vegetation cover, and rock talus/vegetation cover within 4-8 m of the water's edge. Food and Feeding. The diet is mainly fish, but also includes crustaceans, molluscs, small mammals, birds, reptiles, and insects. In southern Brazil, spraint analysis revealed a diet comprising mainly fish (including Loricariidae, Callichthyidae, Cichlidae, Pimelodidae, Auchenipteridae, and Erythrinidae), and also mammals and insects. In the coastal plain of Santa Catarina State, southern Brazil, spraints contained fish (mainly Hoplias malabaricus and Geophagus brasiliensis) and crustaceans (mainly the river crab Trichodactylus fluviatilis). The presence of fruits, reptiles, birds, and mammals in the diet was occasional and opportunistic. On Ibera Lake, Argentina, 205 spraints contained mainly fish (Cichlidae, Characidae, Synbranchidae, Loricariidae, and Erythrinidae), but also crustaceans and molluscs. Seasonal variation was observed in the diet: in the summer, crustaceans and vertebrates (other than fish) increased. A higher percentage of benthic fish species was also observed in the summer, while pelagic and benthopelagic species increased in the winter. Such dietary changes may have resulted from the different habitat used in different seasons, from the lake coast in winter towards a more internal marshy area in summer. Foraging dives last 20-30 seconds. Small prey are eaten while in an upright position at the water’s surface; large prey are taken ashore. Activity patterns. Mainly diurnal, with activity peaks in the middle or late afternoon. May become nocturnal in areas of high human activity. Rest sites are in natural cavities along riverbanks, in excavated burrows, or in dense grass. In Brazil, two large caves were also used as shelters and to raise young. Neotropical Otters mainly use rest sites located high on riverbanks, probably because they are less vulnerable to flooding. Sprainting sites are usually on solid, high and dry areas, in close proximity to deep water; these sites include logs, root systems, rocks, sand bars, and planks under bridges. Movements, Home range and Social organization. Neotropical Otters are graceful swimmers and divers, and are seldom seen out of the water. On land, they move with a humping gait, with the head and tail carried low. Neotropical Otters are solitary, but breeding pairs and females with young are seen occasionally. Population densities vary from 0-8 to 2-8 otters per km of shoreline. Breeding. Mating occurs mostly in spring, but may occur throughout the year in certain localities. Gestation lasts 56-86 days. Litter size may be up to five, but is typically two or three. Births occur in nests of grass and leaves located on the banks of streams, in hollow logs or trees, among root systems, or in cavities excavated by the female. The young are born blind but fully furred. Their eyes open after 44 days, and they start to venture outside the natal den when c. 52 days old. Aquatic activity starts at c. 74 days. Before they are old enough to follow the female, the young spend most of the day playing near the natal den. Females raise the young alone as males do not provide parental care. Status and Conservation. CITES Appendix I. Classified as Data Deficient in The IUCN Red List. Because the Neotropical Otter is secretive and lives in remote areas, the status of populations is unknown in many regions. The major threat for this species is hunting for its pelt. Another threat is water pollution caused by mining and ranching. Neoptropical Otters are sometimes kept in captivity and trained to catch fish. Conservation goals should aim at reducing hunting pressure, protecting areas, and enacting stricter regulations to prevent water pollution. Bibliography. Arcila & Ramirez (2004), Gallo (1991), Helder & Ker De Andrade (1997), Kasper et al. (2004), Lariviere (1999b), Mondolfi (1970), Pardini & Trajano (1999), Parera (1993), Passamani & Camargo (1995), Quadros & Monteiro-Filho (2001), Van Zyll de Jong (1972), 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 pages 642-643, DOI: 10.5281/zenodo.571404