Interesting Creatures… Neotropical Otter (Lontra longicaudis)

Mar 03, 2019 Features / Columnists, Interesting Creatures in Guyana

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The neotropical otter or neotropical river otter (Lontra longicaudis) is an otter species found in Central America, South America and the island of Trinidad. It is physically similar to the northern and southern river otter, which occur directly north and south of this species’ range.
The length of the neotropical otter can range from 90–150 centimetres (35–59 in), of which the tail comprises about a third. Body weight ranges from 5–15 kilograms (11–33 lb). Otters are members of the family Mustelidae, the most species-rich (and therefore diverse) family in the order Carnivora.
This otter is found in many different riverine habitats, including deciduous and evergreen forests, savannas, llanos and pantanal. It prefers to live in clear fast-flowing rivers and streams. It is a relatively solitary animal and feeds mostly on fish and crustaceans.
The neotropical otter is covered in a short, dark greyish-brown pelage. Fur color is lighter around the muzzle and throat. They possess a long wide tail, with short stout legs and fully webbed toes. Sexually dimorphic, the males are about 25% larger than the females.
Body mass of the otter generally ranges from 5 to 15 kilograms. Neotropical otters will communicate with nearby otters via scent marking. Communication may also occur via whistles, hums, and screeches.
The dental formula seldom varies from that of Eurasian otters, except in the few cases of otters that have dental anomalies.
The neotropical otter’s diet consists mostly of fish and crustaceans making up 67% and 28%, respectively, of its total diet. The otter will also occasionally feed on mollusks and small mammals. This otter is known to occasionally attack fishnets for a source of prey, hindering fishing productivity. Otters living near marine habitats can have a much higher proportion of crustaceans in their diets.
Seasonality also greatly affect otters’ food choice. During the dry season, when less fish and crustaceans are available, one study found a higher proportion of frogs in otters’ diet. Though, during this time, anurans and reptiles still made up a very small percentage of the total diet. This might also be due to the fact that certain frogs mate during the dry season, so the frogs are easier prey. All in all, the distribution of available food species in a particular area roughly correlates to the percentage of each species found in otters’ diet.
Breeding occurs mostly in spring. Gestation will last 56 days and produce a litter of 1–5 pups. The pups are born blind yet fully furred. They will emerge from their mother’s nest when they are about 52 days old and begin swimming at 74 days. They are raised completely by their mother, as males do not provide any parental care. The male will only spend a single day with the female during breeding season. The female must keep her pups safe from predation by other neotropical otters. In one captive breeding situation, cannibalism by the mother may have occurred, though it was not confirmed.
This otter is listed as Near Threatened by the IUCN. The species is, moreover, currently protected in Argentina and many other South American countries. Heavy hunting for its fur in the 1950s–1970s resulted in much local extinction over the otter’s range. Illegal hunting, habitat destruction through mining and ranching, and water pollution still affect the population of the neotropical otter. Although there have been attempts at captive breeding, they are largely unsuccessful.
Most negative feelings about otters arise from fishermen who compete with the otter for fish. More data is needed to determine how much overlap exists between the fishermen’s desired catch and the otter’s diet. The highest competition between Neotropical otters and fishermen occurs during drought conditions. Fishermen may move out of their regular fishing areas, into deeper pools where the otter usually hunts in the absence of people.
In a study on local fishermen’s attitudes, the study revealed that fishermen’s knowledge aligned with scientific data about the Neotropical otter’s behavior, body description, and other data. Because the fishermen’s facts aligned with scientific knowledge, scientists could then trust the fishermen’s first-hand accounts about problems they experience with otters.
Fishermen reported that otters will damage their fishing gear, but do not damage crab and shrimp nets.
Neotropical otters are threatened by habitat degradation associated with: agriculture, soil compaction, pollution, roadways, and runoff. Also, when forests are cleared for cattle grazing, heavy vegetation (which is the otter’s preferred habitat) near streams is also cleared or trampled by cattle. This species is a very important ecological indicator because they prefer ecologically rich, aquatic habitats and have a low reproductive potential. [Source: Wikipedia]

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