Neotropical otter (Lontra longicaudis)

Also known as: La Plata otter, long-tailed otter, neotropical river otter and South American river otter
French: Loutre À Longue Queue, Loutre D'Amérique Du Sud
Spanish: Gato De Agua, Lobito De Río, Lobito Del Plata, Nutria De Agua, Perro De Agua, Taira
GenusLontra (1)
SizeHead-body length: 36 - 66 cm (2)
Tail length: 37 - 84 cm (2)
Weight5 - 15 kg (2)

Classified as Data Deficient (DD) on the IUCN Red List (1) and listed on Appendix I of CITES (2).

Also known as the long-tailed otter, the Neotropical otter (Lontra longicaudis) possesses a remarkably long, cylindrical tail which makes up over a third of its total body length. Like other otters, the Neotropical otter is an efficient swimmer, with an elongated body, flattened head, short limbs and webbed feet. Its nostrils and small round ears can be closed while swimming (2).

The greyish-brown fur of the Neotropical otter is dense and short. Its underfur is protected by a layer of longer, coarse guard hairs. Lighter patches of fur occur around the throat area. This species has the typical robust shape and size characteristic of other American river otters (2).

Male and female Neotropical otters differ in appearance, with the male being up to 25 percent larger than the female (2). 

The vocal communications of the Neotropical otter have been described as whistles, hums and screeches, and a “hahh” alarm call (2).

The Neotropical otter’s range extends from north-western Mexico, south to Uruguay, Paraguay and northern and central Argentina (1). This species is the most common otter in Mexico, and has the widest distribution of the three South American otters in the Lontra genus (2) (4).

The Neotropical otter occupies a wide range of habitats, including deciduous and evergreen forest, rainforest, and coastal savanna swamps. Within these habitats, the presence of potential den sites and abundant vegetation are essential (1).

The Neotropical otter shows a preference for clear, fast-flowing rivers, and is absent from slow lowland rivers laden with silt (2). This species is most commonly found in areas with extensive waterways, low pollution levels, and low human density. However, the Neotropical otter shows great adaptability and has also been found occupying areas close to human activity, such as irrigation ditches, rice fields and sugar cane plantations (1).

The Neotropical otter typically forages in mid- and late afternoon. However, in areas of human disturbance, foraging may occur at dawn and dusk, and in some cases otters may even become completely nocturnal (2). The diet of the Neotropical otter consists mainly of fish, molluscs and crustaceans, but it will also opportunistically prey upon small mammals, birds, reptiles and insects (1) (2). Scat samples of the Neotropical otter have even included the remains of large mammals such as armadillo (Dasypus spp.) and capybara (Hydrochoerus hydrochaeris) (5). The foraging dives of this species last 20 to 30 seconds, and small prey items are eaten in the water while large prey items are taken ashore (2).

The Neotropical otter usually breeds in spring, but breeding may occur throughout the year in certain regions. The gestation period lasts 56 days and the litter size varies from 1 to 5 cubs (1). The male Neotropical otter provides no parental care. Neotropical otter cubs are born blind but fully-furred (2). The cub’s eyes open at around 44 days and they will first leave the den at around 52 days (6). At around 74 days old, the female starts to teach the cubs to swim (6). The Neotropical otter reaches sexual maturity at around two years old (2). 

This species is mostly solitary, although it may be found in pairs during the breeding season. Communication between Neotropical otters with neighbouring territories occurs through scent-marking with faeces, known as ‘sprainting’ (2 

In 1970 alone, 14,000 Neotropical otter pelts were exported from Peru. This figure is believed to represent only half of the animals killed. Excessive hunting between 1950 and 1970 resulted in the local extinction of the Neotropical otter over parts of its former range (2). Despite being listed as a protected species since 1973, illegal hunting continues to threaten the Neotropical otter (1) (7).                                                                                                   

The major threat faced by the Neotropical otter today is the loss of suitable habitats through human activities such as mining, ranching and water pollution (2). As industrial development encroaches upon the habitat of the Neotropical otter, pesticides, fertilisers and heavy metals are entering the water system. These chemicals accumulate in prey species, which are then ingested by the otter. This has been blamed for Neotropical otter deaths and reproductive failure (8).

Neotropical otters are naturally curious and show little fear of humans, making them vulnerable targets. This species is sometimes kept in captivity and trained by fishermen to help catch fish (1).

The Neotropical otter is listed as Endangered under the U.S Endangered Species Act (7), and international trade in this species is banned under its listing on Appendix I of the Convention on International Trade of Endangered Species (CITES) (3). It is also listed as Endangered by and by the Mexican Ministry of Ecology (1). 

This species is listed as a priority species by the Fundacion Vida Silvestre Argentina, which has made efforts to gather more biological information on the Neotropical otter and prevent illegal hunting. The Neotropical otter is highly protected in most countries in its range, but enforcement of the law varies (2).

As little is known about the abundance, distribution and behaviour of the Neotropical otter, conservation efforts should focus on identifying key habitats, protecting areas where high populations remain, and reducing water pollution (1).

In the Ibera lagoon, Argentina, the population of Neotropical otters recovered rapidly after excessive hunting of this species was bannedin 1983 (2), indicating that its populations may be able to recover well when properly protected.

Find out more about the Neotropical otter and its conservation:

Learn more about otter conservation:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (August, 2011)
  2. Larivière, S. (1999) Lontra longicaudisMammalian Species, 609: 1-5. Available at:
  3. CITES (August, 2011)
  4. Gallo, J.P. (1991) The status and distribution of river otters (Lutra longicaudis annectens Major,1897) in Mexico. Habitat1: 57-62.
  5. Quintela, F.M. and Gattii, A. (2009) Armadillo in the diet of the Neotropical otter Lontra longicaudis in southern Brazil. IUCN Otter Specialist Group Bulletin26(2): 78-81.
  6. Jacome, L. and Parera, A. (1995) Neotropical river otter, Lutra longicaudis, breeding under captive conditions in Buenos Aires Zoo, Argentina. IUCN Otter Specialist Group Bulletin, 12: 34-36.
  7. U.S. Fish and Wildlife Service: Species profile – Long-tailed otter (Lontra longicaudis) (August, 2011)
  8. Maldonaldo, J.R.E. and Lopez Gonzalez, C.A. (2003) Recent records for the Neotropical river otter (Lontra longicaudis) in Guerrero, Mexico. IUCN Otter Specialist Group Bulletin, 20(2): 65-68.