Giant Otter / Brazilian Otter / River Wolf (Pteronura brasiliensis)
Order: Carnivora, Family: Mustelidae
Giant otters can grow up to 6 feet long, with males usually longer than females.
Male otters weigh between 217 and 267 pounds, and females average 184 to 217 pounds.
The giant otter has a round head with small, low-set ears. It has large eyes; short, thick legs; a flattened tail; and large webbed feet equipped with strong claws.
Its thick, water-repellent coat is a very dark burnt umber, with pale markings on the throat.
II. GEOGRAPHICAL RANGE AND HABITAT:
- Giant otters can grow up to 6 feet long, with males usually longer than females.
- Male otters weigh between 217 and 267 pounds, and females average 184 to 217 pounds.
- The giant otter has a round head with small, low-set ears. It has large eyes; short, thick legs; a flattened tail; and large webbed feet equipped with strong claws.
- Its thick, water-repellent coat is a very dark burnt umber, with pale markings on the throat.
- The giant otter's range extends throughout South America, excluding Argentina, Chile and Uruguay.
- The giant otter inhabits tropical rain forest, making its home in large, slow-moving freshwater rivers, creeks, lakes, and sometimes reservoirs of small dams and agricultural canals.
IV. LIFE CYCLE/SOCIAL STRUCTURE:
- Giant otters eat fish — preferably perch, catfish and members of characin family. They also occasionally feed on small caimans, crustaceans and small snakes.
V. SPECIAL NOTES/ADAPTATIONS:
- Giant otters live, hunt and play together in social groups (called holts) comprising male and female parents and their offspring.
- Each holt has its own territory, and different holts do not overlap or fight with one another.
- Giant otters hunt in groups in deeper water, and solo in shallow areas. An individual otter can eat 6 to 10 pounds of food per day.
- Otters communicate by vocalization and scent marking.
- Giant otters reach sexual maturity at 2 to 3 years of age; they soon leave the holt to search for vacant territory or a mate. Some "singles" return to the holt; male and female otters bond for life.
- Gestation lasts for 65 to 70 days. The dominant female in the holt gives birth to a litter of one to five young ashore in an underground den. Young born mainly during the dry season. The remainder of holt helps care for the new pups.
- Pups stay within the den for the first two months; when the group hunts, an older sister or brother cares for young.
- Young travel out of den, learn to swim and participate in group hunts at 2 months of age; they also begin to eat fish then, but continue to nurse until they're 5 months old.
- Giant otters live for an estimated 10 to 13 years.
VI. ENVIRONMENTAL IMPACT:
- The giant otter takes advantage of its good eyesight for hunting, but also uses its hearing and sense of smell.
- Giant otters can kill a caiman or anaconda.
- The otter's webbed feet and stout flattened tail guide it through submerged vegetation; the otter keeps its ears and nose closed when diving for prey.
VII. POPULATION STATUS:
- The giant otter is at the top of the rain-forest food chain.
- It has no predators except humans.
VIII. MORE GIANT OTTER FACTS:
- The giant otter is threatened, and may become truly endangered if causal factors (such as fur hunting, habitat destruction, excessive fishing and water pollution) continue. The population has been reduced to an estimated 2,000 to 5,000 individuals.
- The species is protected by law.
- The giant otter is the longest (and one of the rarest) of any otter.
- The giant otter is the South American cousin to the sea and river otters of North America, Europe and Africa. It is twice as large as its North American counterparts.