Lontra felina Gray 1843

29.

Marine Otter

Lontra felina

French: Loutre chungungo / German: Stidamerikanischer Meerotter / Spanish: Chungungo

Taxonomy. Mustela felina Molina, 1782,

Chile.

The Marine Otter was previously included in the genus Lutra. Monotypic.

Distribution. Pacific coast from N Peru to S Chile, and extreme S of Argentine Patagonia.

Descriptive notes. Head-body 53.3-78.7 cm, tail 30-36.2 cm; weight 3.2-5.8 kg. The smallest of the South American otters. The pelage is dark brown through-out except for a grayish neck and throat. Large vibrissae occur on each upperlip. All the feet are fully webbed. The skull is small and flat, with a broad rostrum.

Habitat. Marine Otters are found in marine environments, along rocky coasts that harbor a high diversity of prey. They spend most of their time within 150 m of shore, but occasionally may venture into freshwater tributaries flowing into the sea.

Food and Feeding. The diet is primarily crustaceans, molluscs, and fish, but also includes birds, small mammals, and fruit. Along the Chilean coast, the diet consists of crabs (69-8%), fish (19:9%), shrimp (6:4%), and molluscs (3-9%). On the Valdivian coast in the south of Chile, spraints contained 25 species: 52% crustaceans, 40% fish, and 8% molluscs. Marine Otters showed opportunistic feeding behavior, selecting prey seasonally according to their availability. Marine Otters fish by first swimming to a hunting area, where they then dive underwater for 6-64 seconds. Captured prey are consumed in the waterif they are small enough to be handled easily, or taken ashore if larger. Crabs are almost always taken ashore. Prey can be carried in the mouth, or carried on the belly while swimming dorsally. Unlike Sea Otters, Marine Otters do not use rocks as anvils to crack open bivalves or shellfish. At Isla Choros, northern Chile, Marine Otters spent more time foraging in a wave-protected site compared with a wave-exposed habitat. Successful dives reached 26-9% in the wave-exposed habitat and 38-2% in the wave-protected habitat. Foraging dives were 18% shorter in wave-exposed as compared with wave-protected habitat.

Activity patterns. Mainly diurnal. Marine Otters spend about 40% of their time hunting and 60% resting or grooming. They make extensive use of caves, rock crevices, and natural cavities for resting sites. Many areas used for resting at low tide are underwater during high tides.

Movements, Home range and Social organization. Marine Otters are strong swimmers, but their daily movements occur within 150 m ofthe coast. Long coastal movements are not documented. Marine Otters are solitary and seldom hunt in groups; observed groups are likely to consist of a female with her young. Among adults, home ranges overlap. Six Marine Otters were radio-tracked in central Chile. Females exhibited intra-sexualterritoriality, but there was no territoriality between males or between sexes. Home ranges were less than 4134 m long and less than 110 m wide; range size did not differ between sexes. Marine Otters concentrated their activity in the littoral zone and spent 81% oftheir time on land, mostly resting. Core areas were associated with resting places and dens. Population density varies from 0-04-10 otters per km of coastline.

Breeding. Mating occurs in December orJanuary. Gestation lasts 60-65 days and births take place in January, February, or March. Females give birth in rocky caves; these dens are spaces between boulders that remain above water even at high tide, and many have underwater entrances. Litter size is two to four. The young remain with their mother for up to ten months.

Status and Conservation. CITES Appendix I. Classified as Endangered in The IUCN Red List. It is estimated that fewer than 1000 Marine Otters remain, including a Peruvian population of 200-300. This species is protected in Argentina, Chile, and Peru. Major threats include human occupation of the coast, water pollution, and illegal killing for their pelts or by fisherman who blame Marine Otters for the reduction of local fish or shrimp populations.

Bibliography. Castilla (1981), Eisenberg (1989), Lariviere (1998), Medina (1995), Medina, Boher et al. (2007), Medina, Rodriguez et al. (2004), Ostfeld et al. (1989), Sielfeld (1983), Van Zyll de Jong (1972), Wozencraft (2005).