Species Profile: Giant Otter
The Giant Otter is the most recognizable otter. It is, as its name says, giant. From head to tail, it reaches an astounding six feet, the longest of any otter. Although the Sea Otter can weigh more, the Giant Otter is clearly the longest. It has such distinct characteristics, there is some question as to whether it is truly a direct member of the otter family.
The endangered Giant Otter lives in the tropical rainforest in South America in social groups of up to 10 individuals, who hunt, sleep and play together. They are referred to as "river wolves" locally.
The Frankfurt Zoological Society in 1990 initiated a significant research project on Giant Otters in Peru which continues currently. This research has helped to better understand these unique otters and help us protect them into the future.
When they are two or three months old, they start to travel out of the den and sometimes participate in group hunts. The young otters eat fish as they start hunting, but are still dependent on their mother's milk until they are 5 months old. The Otters reach sexual maturity after two or three years, where they leave the group and wander about in search of vacant territory or a mate, both of which are hard to find. Some "singles" return back to their group. Others find a vacant territory and a mate and start a new group.
We also over-fish by depleting the fish population in certain areas through constant fishing or use of nets to fish in rivers. Over-fishing can only be done in the tropical rainforest for a few consecutive years. After that, it has disturbed the ecological balace and the ecosystem gets out of wack, with the entire food chain damaged. Because of this, the otter's main food source is depleted.
Water pollution is also a very bad thing. In some places, mercury is used to extract gold from river sediment. In the final part of separating, the mercury-gold compund is heated until the mercury turns into a gas and evaporates. Two grams of mercury are needed to gain one gram of gold! Tons of mercury is released into the environment each year this way. Fish that were examined from different parts of South America, from the Manu Preserve to the fish marked of Puerto Maldonado, for mercury contamination found concentrations that were far beyond the legal limits for selling fish in the U.S. and Germany. Even more surprisingly, the fish in the Manu Preserve, far away from the mining area, were highly contaminated due to fish migration and mercury evaporation.
A very direct threat to otters is poaching. Giant Otters are protected by right and law, but still they are getting killed. Usually, the first otter to be killed is the dominant female, for she usually approaches the canoe first. This means that there is a large disturbance of the group's social structure AND the death of the female's litter. In the early days, Giant Otters were killed and eaten, despite their horrid taste, because there was nothing to eat. They are also viewed as competitors for fish, especially in over-fished areas near towns. Currently they are primarily killed for their dense fur.
Giant otters are very sensitive to human disturbance. Disturbances within the surroundings of the den may have fatal consequences for the young. The Manu National Park and the indian settlement of Tyakome are visited by humans. The largest six lakes are the home for more than seventy-five percent of the otters of Manu National Park, and are regularly frequented by visitors. Canoeing is a serious menace to the otters of Manu, especially in the breeding season. Tourisim is a large threat for otters, too, unless its well planned and well organized. The otters get scared by human presence and the reproductive rate is lessened.
Otters could also die of a disease called parvovirosis, a disease common to dogs and cats. When close to human settlement, Otters may catch the disease. The disease can kill large numbers of Otters. A pet disease also killed hundreds of black footed ferrets in North America.
Spanish: Lobo del Rio, Lobito de Cola Ancha, Arirai, Lobo
French: Loutre geante du Bresil
Dutch: Riesen Otter
Italian: Lontra gigante del Brasile
Puerto Rican: Ariranha
Other scientific name: Lutra Brasiliensis