Nicaragua’s Fascinating Perro de Agua

Found in a number of Nicaragua’s Ramsar Sites, the neotropical otter (Lontra longicaudis) is a fascinating animal, at home in the water and on land. Also known as the perro de agua (river dog), la plata otter, long-tailed otter and South American otter, this carnivorous mammal of the mustelidae family is listed as ‘data deficient’ by the International Union for Conservation of Nature (IUCN), meaning that there is insufficient data to determine its conservation status. However, it is listed as endangered by the International Trade of Endangered Species of Wild Fauna and Flora (CITES) and is currently a protected species in Nicaragua.

With its sleek body, short limbs, webbed feet, flattened head and long, cylindrical-shaped tail, the perro de agua is an exceptionally good swimmer, cutting through the water at an impressive speed when necessary. It is able to close its nostrils and small round ears and its nostrils when swimming. It has dense, short greyish-brown fur, with underfur insulated by long coarse hairs referred to as guard hairs. The fur around its throat area is lighter in color. Measuring between 36 and 66 cm, with tail length between 37 and 84 cm, adult males are generally up to 25 percent bigger than females.

They prefer living close to fast-flowing rivers in deciduous, evergreen and rain forests, as well as coastal savanna swamps. When left undisturbed, otters prefer to forage in the mid-afternoon, but are known to forage at night in areas where humans are present. As carnivores, they eat mainly fish, crustaceans and molluscs, but will also eat birds, reptiles, small mammals and insects when these are available. Analysis of scat samples reveal that otters may even eat mammals as large as capybara and armadillo, although it is not known if they have caught these or are feeding on remains of prey caught by other animals.

More often than not, they are solitary animals, socializing only for breeding purposes. In some areas breeding may take place all year around, but they usually breed in spring, with the gestation period lasting 56 days and litter sizes varying from one to five pups, also referred to as cubs or whelps. Newborns are covered in fur, but their eyes only open when they are around 44 days old, and they leave the den around eight days after that. The mother teaches her little ones to swim from about 74 days of age. Their vocal communications include hums, whistles and screeches and they mark their territories with a scent-marking ritual known as ‘sprainting’.

The main threats to the continued existence of the perro de agua are illegal hunting, habitat destruction and river pollution. The poisoning of the water with pesticides, fertilizers and other chemicals poisons food sources, which in turn poisons otters, or results in a failure to breed successfully. Recommendations from the IUCN to prevent the extinction of the perro de agua include identifying key habitats and protecting them, as well as formulating stricter regulations to prevent toxic waste from being released into rivers.