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Meet the Giant River Otter

The Giant River Otter, a majestic carnivorous mammal with a dense velvety pelt and long body, loves to spend time in the freshwater rivers and streams in the Amazon River Basin. Did you know otters can close their noses and their ears when they swim?! Giant River otters differ from other river otters in several ways, one being size. Males today can reach 5.6 feet in length, but even larger males were reported years ago. They can weigh between 57-71 pounds. Giant River Otters are quite a bit larger than the river otters I've seen!

Another difference is their short fur. Giant otters have the shortest fur of all the otters, but it is so thick that no water can reach their skin! Giant otters also have unique markings on their throats, which allow them to be identified from birth. Giant otters will sometimes display their throats upon meeting as if to say, "Hey! It's me... you can tell by my spots!"


Otters pickout a home based on availability of food, and show a strong preference for gentle sloping banks and rocky river bottoms. They are terrestrial animals though, constructing their communities on land. Amazingly the Giant River Otter builds little communities beside the rivers, with dens, campsites, and latrines (bathrooms)! The communal latrines are where all the Otters do their business to keep their homes clean! They have been observed patrolling different sites and building exit doors in their dens to escape high waters during the rainy season. These animals are highly intelligent and social, not so different from you and I!

When living in their family communities, otters have no predators. They are protected by numbers for other predators, and only Otters separated from their families are at risk of Caiman or Jaguar attack. Having no predators of their own makes them apex predators, feeding on catfish, piranha, and especially a type of fish called cichlids, which they love. It’s probably their favorite food, as studies have shown it in 97% of Otter scat (poop)! Otters are responsible for feeding themselves, usually hunting alone with their excellent eyesight and chomping down on dinner with their strong jaws. Their webbed feet and sharp claws help them grab and hold onto their prey, which they consume immediately - head first.

Otter Families and Babies

Giant River Otter family groups are not that dissimilar from your own family! Most families consist of between 4 and 8 otters and they are strongly bonded. They play, eat, and sleep as a family unit. The families are territorial, keeping other groups out by clearly marking their dens and latrines with gland secretions and vocalizing with barking sounds and snorts to warn intruders away. Your Mom and Dad are probably the leaders of your household, but in Otter groups there is more shared responsibility. Despite being territorial, Otters are mostly peaceful, avoiding conflict whenever possible even with outside groups.

The female Otter will give birth to an average of two blind pups in the comfort of the den during the dry season, in August or September. The Otter pups will start leaving their dens in October, when the water levels are the lowest, to allow them to learn to swim, by around 12 weeks old. All of the family members will help the baby otters, by catching enough fish to make sure they are fed. They are weaned at 9 months and from that point on will do all their own hunting. The offspring will leave the group to find their own mate and new family, at around 2 to 3 years of age. Interestingly, the presence of human faces and voices during pup rearing is problematic for

Otters! It can inhibit the mother’s ability to feed her pups and can cause neglect and even abandonment. In captivity Otters are given extreme privacy during this time as they find humans highly stressful. Otters have a lifespan of up to 8 years in the wild.


Otters used to be hunted for their soft, velvety pelts. This practice is called poaching, and was a very lucrative business for hunters. Giant River Otters are now on the endangered list; there may be as few as 5,000 left. But there is good news! Protected areas have been created for the otters where they can live peacefully and thrive without human disturbance.

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