The Giant Otter (Pteronura brasiliensis), also known as the giant river otter, is a South American carnivorous mammal. The word "otter" came from Old English word otor or oter. This and has cognate words in other Indo-European languages which stem from Proto-Indo-European "wodr" which ultimatly gave rise to the English word 'water'. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, as well as the largest, with only the sea otter being heavier, reaching up to 1.7 metres (5.6 ft) and weighing up to 70 lbs. Atypical of mustelids, the giant otter is a social species, with family groups typically supporting 3-8 members made up of brothers, sisters, uncles, aunts, parents, etc. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial, and aggression has been observed between groups. The giant otter is diurnal, being active exclusively during daylight hours. It is the noisiest otter species, and distinct vocalizations have been documented that indicate alarm, aggression, and reassurance.
The giant otter ranges across north-central South America; it lives mostly in and along the Amazon River and in the Pantanal.
Its distribution has been greatly reduced and is now discontinuous. Decades of poaching for its velvety pelt, peaking in the 1950s and 1960s, considerably diminished population numbers. The species was listed as endangered in 1999 and wild population estimates are typically below 5,000. The Guianas are one of the last real strongholds for the species, which also enjoys modest numbers — and significant protection — in the Peruvian Amazonian basin. It is one of the most endangered mammal species in the neotropics. Habitat degradation and loss is the greatest current threat. The giant otter is also rare in captivity; in 2003, only 60 animals were being held.
The giant otter shows a variety of adaptations suitable to an amphibious (which means they do well on land and in water) lifestyle, including exceptionally dense fur, a wing-like tail, and webbed feet. The species prefers freshwater rivers and streams, which are usually seasonally flooded, and may also take to freshwater lakes and springs. It constructs extensive campsites close to feeding areas, clearing large amounts of vegetation. The giant otter subsists almost exclusively on a diet of fish, particularly characins, piranhas, and catfish, but may also eat crabs, turtles, snakes, and small caiman if fish are unavailable. It has no serious natural predators, although it must compete with other predatory species, including jaguars, anacondas, caimans, and bull sharks for food resources.
Giant otters all work together to hunt prey and drive off other predators. They'll often snort snot and mucus when they get excited or when a predator comes their way. They are also easy to identify because of the white speckled patterns on their throats, and their broad, paddle-shaped tails.