Giant otter  (Pteronura brasiliensis)

The giant otter, known locally as the 'river wolf', is one of South America's top predators and is the largest of the otter species in terms of length (4). The long, sinuous body is covered with velvety, reddish-brown fur, which is thick and water-repellent. A patch of cream colouring is present on the throat and chin, the pattern of which is unique to each individual. The short legs end in large webbed-feet and these, along with the rudder-like tail, allow the otter to move quickly through the water. The movement of prey is detected by the large eyes and sensitive whiskers (2) (5).

Endemic to South America, although absent from Argentina, Uruguay and Chile (5), the giant otter is seen within the Orinoco, Amazon and La Plata River systems (6).

Found in slow-moving rivers, lakes and swamps, preferring gently sloped riverbanks and secluded areas with overhanging vegetation (2).

Giant otters generally live in family groups of three to nine individuals, composed of a breeding pair and their offspring (6). These groups, also known as 'holts' (4), rest, play, sleep, travel and fish together (6). Members of the group use communal latrines and rub their faeces and urine into the earth with their front paws, in order to advertise the group's residency (5).

Breeding can take place throughout the year, although most young are born in during the dry season. Litter size varies from one to five 'kits', following a 52 to 70 day gestation. The new cubs are cared for by both the parents and older siblings. At two to three weeks they are put in the water by their mother, and at three to four months of age, the cubs begin hunting and travelling with the family. They are weaned at nine months, and are as efficient hunters as their parents by the age of ten months, although they remain with the family group for at over another year (6).

These otters are diurnal and semi-aquatic, and despite their clumsy appearance on land they are known to travel large distances between areas of water. The diet is composed almost exclusively of fish (6), but they are also known to eat caimans, anacondas, other snakes and even the occasional heron (7).

Up until the 1980s these otters were excessively hunted for their valuable fur (7) (8); their naturally curious disposition making them particularly easy targets. The fur trade is less of a threat today thanks to protective legislation, but illegal hunting does still occur. Some cubs are taken from the wild to be kept as pets, and usually die in the hands of inexperienced caretakers. Habitat loss and pollution are currently the major threats to the survival of this species; with the areas in which they live being destroyed and degraded by mining, logging, damming and over-fishing (2) (8).

Giant otters are protected through much of their range and are listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), which effectively bans international trade (3). In 1990, the IUCN developed an action plan for the conservation of otter species. It recommended a number of conservation measures for giant otter including continuing studies on the ecology and requirements of this remarkable species, improving the management of existing protected areas in which it occurs, and stricter regulations to prevent the escape of toxic waste from factories, human settlements and agriculture into the surrounding rivers and wetlands. Education campaigns are also required to raise awareness of the plight of this fascinating species (8). The charismatic giant otter is also beginning to play a role in 'eco-tourism' that may provide some financial incentives for protection measures (7).

To learn more about the giant otter and its conservation see:

• Giant Otter Research:
  www.giantotterresearch.com
• IUCN Otter Specialist Group:
  www.otterspecialistgroup.org

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:
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