Giant Otter

Pteronura brasiliensis

 

Identification

Size: From nose to tail, giant otters are 145 to 180 cm long. Males are generally larger than females. Their tails are flattened and flanged, and range from 45 to 65 cm long. Their ears are very small, and their eyes very large.

Color: Reddish brown back, with an irregular white patch on the throat.

Nose: The giant otter's nose is covered in fur.

Feet: Large, strong, webbed feet with strong claws.

Fur: The fur is fine, thick, and sleek. The guardhairs are 8 mm long, and the underhairs are 4 mm long.

Track/Sign: No info at this time.

 

 

Ecology

Habitat: Tropical rainforests waters in South America.

Range/Distribution: The population has been reduced from its original range (Venezuela to northern Argentina) generally to the waterways of the Brazilian rainforest.

Threats: Over-fishing, pollution, habitat destruction, and poaching are the main threats to this otter. In many places, mercury is used to extract gold from river sediments. When the gold is obtained, they are separated by heating until the mercury evaporates into the environment. Tons of mercury are released every year, and it contaminates everything in the area. Disturbances near the den during breeding season can lessen the reproductive rate because the otters get scared. Disturbances when the pups are young can also be highly detrimental..

Conservation Status: Endangered

 

Food: Giant otters are at the top of the Brazilian food chain. They eat fish (they prefer perch and catfish), reptiles (small caiman), crustaceans, snakes, and birds. Giant otters hunt in shallow water when alone, and in deeper water when in groups. They rely mostly on their eyesight to catch prey. They eat 6 to 9 pounds of food per day!

 

Behavior

Life Cycle: The gestation period for giant otters is 65 to 72 days. They are born in the dry season, between May and September. The dominant female is the only female that breeds, but the whole holt helps to raise the young. The pups stay in the den for the first two months of life. They then start to travel outside of the den, and start learning to swim. They begin to participate in group hunts and start eating fish soon after, but rely on their mothers' milk until they are about five months old. Giant otters are fully mature at two to three years of age, at which time they will probably leave the holt to find new territory, a mate, or a new group (although some otters will stay with their families long-term).

Social: Giant otters are incredibly sociable. They live in family groups (holts) of ten or more, sometimes up to twenty otters! These groups consist of male and female parents, their young, and sometimes a couple of non-related otters that have joined their holt. They are very social and don't like to be alone, but they are also very territorial. One holt encroaching on the territory of another is one of the few things that may actually lead to violence between these generally very playful otters.

Individual:

 

About:

Names:

Brazilian Otter, River dog
Spanish: Lobo del Rio, Lobito de Cola Ancha, Arirai, Lobo
French: Loutre geante du Bresil
Dutch: Riesen Otter
Italian: Lontra gigante del Brasile
Brazilian Portugese: Ariranha
Other scientific name: Lutra Brasiliensis

 

Subspecies (two proposed subspecies):

Pteronura brasiliensis brasiliensis- 5 premolars in upper jaw

Pteronura brasiliensis paranensis- broader skull, 4 premolars in upper jaw

Recent research has indicated that there is not enough difference in mtDNA between these groups to warrant calling them distinct subspecies, but research has yet to be done in other areas. See this for the full article.

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