Endangered Species in the Amazon Rainforest | Causes & Examples
There are millions of species that live in the Amazon Rainforest. Some of these species are endangered, mainly due to habitat loss. The Giant River Otter is ...
Giant River Otter
As the world's largest species of otter, the <anchor>Giant River Otter</anchor> can be as long as 6 feet. It can only be found living in three river systems, which are the Amazon, Orinoco, and La Plata. They live in family units and will also fish together as a unit. They mainly eat fish, but they will also supplement their diet with crustaceans, snakes, and other animals in the river.
Giant Otter | Habitat, Size & Adaptations | Study.com
Menu

# Giant Otter | Habitat, Size & Adaptations

- Lesson

- 

Additional Info

Christina Harvey, Amanda Robb

- Author

Christina Harvey
Christina graduated with a Master's in biology from the University of Louisiana at Lafayette. She is a current PhD student in biology at Wake Forest University, and has been teaching undergraduate students biology for the last three years.

View bio

- Instructor

Amanda Robb
Amanda has taught high school science for over 10 years. She has a Master's Degree in Cellular and Molecular Physiology from Tufts Medical School and a Master's of Teaching from Simmons College. She is also certified in secondary special education, biology, and physics in Massachusetts.

View bio

What is a giant otter? Learn about the giant river otter's habitat, population, and behavior. Explore some characteristics of giant otters and learn fun facts.

Updated: 11/21/2023

## Table of Contents

Show

Frequently Asked Questions

#### Are giant otters friendly?

Giant river otters are typically skittish of humans in the wild, though they may become defensive when their young or homes are threatened. In captivity, giant river otters may develop relationships with handlers. However, these are large, potentially dangerous animals that should be handled with caution by educated keepers.

#### Why is the giant otter going extinct?

The giant river otter is often poached by local fishermen because they compete by hunting lucrative fishing populations. Giant otters are also experiencing habitat loss as water quality is diminished or wetlands are converted into agricultural lands.

#### Where do most otters live?

Otters are aquatic mammals. Because of this, they are often found in fresh-water wetlands such as river basins with moving freshwater streams.

## Table of Contents

Show

The Giant Otter

The giant otter (or giant river otter) is a species of otter that is native to South America. The scientific name for the giant otter is Pteronura brasiliensis, and like all otters, it is a member of the family Mustilidae. Mustelids are carnivorous mammals that typically have long bodies, shorter legs, and possess well-developed anal glands that produce a musky scent. Mustelidae also contains animals such as ferrets, weasels, martens, badgers, wolverines, and polecats.

Giant otters are large aquatic mustelids of South America.

A photograph of a giant otter swimming.

While most mustelids are small, the giant otter is one of the largest mustelids on the planet. The giant river otter size is a remarkable six feet in total length from the tip of the nose to the end of the tail. They can also weigh up to 75 pounds. They are rich, dark brown in color, and typically have white markings on their chin and neck.



5K
views

The Giant Otter's Habitat

The Amazon Basin (green) is a common habitat for the giant otter.

A map of South America with the Amazon Basin marked in green.

Giant sea otters are native to the fresh-water aquatic habitats of the Amazon. More specifically, these mustelids are most commonly found in three river systems in northern South America: the Orinoco, Amazon, and La Plata. These habitats are highly vegetated wetlands sometimes occurring within south America's vast expanse of rainforests.



Are Giant Otters Endangered?

Giant otters are classified as endangered by the International Union for Conservation of Nature (IUCN). It is believed that this status is due to two reasons:

Giant river otters are large aquatic animals that require a good amount of space in order to thrive. Every year, more and more of the wildlands of South America are converted into agricultural lands. These fields and pastures are not suitable for giant otters, and many of them are displaced or die. In addition, aquatic ecosystems are sensitive to chemical changes. Recent fires throughout the world have increased the ash levels in the atmosphere. This ash condenses in bodies of water and changes the pH, sediment load, and visibility of aquatic systems. Highly sensitive organisms like fishes and crustaceans may not be able to survive these quick changes in chemical properties, and as a result, populations may perish. When fish decline in abundance, river otters lose their primary food source and are no longer sustained.

Giant otters have also had a history of conflict with local populations. Many locals make a living by fishing the diverse river systems in northern South America. Because river otters are voracious mammals, some fishermen may consider them competition. As a result, giant otters have been frequently poached and their numbers reduced.



Giant Otter Adaptations

Giant river otter adaptations have allowed it to live a life that is mostly aquatic. These large otters have sleek fur that is water-repellent enabling them to stay warm even when gliding through cold water. Another benefit of this fur is its ability to dry quickly when leaving the water, further adding to its ability to retain heat and prevent low body temperatures. They also prevent cold water from entering the body by closing their nostrils and ears while swimming. They are made remarkable swimmers thanks to two unique features:

- Webbed feet
- Strong, thick tails

Webbed feet allow them to push against water and move forward at a rate that much exceeds their relatives without this extra skin. Their strong tails also act like rudders, beating to help propel them forward and steer them with surprising accuracy. Despite their large size, these South American river otters are nimble and agile even in fast-moving waters.

And being good swimmers doesn't just come with bragging rights; giant otters must be able to swim with such high skill just to survive. These animals consume just shy of ten pounds of fish daily. To maintain that level of consumption, giant otters must be able to outswim fish and catch them with relatively high success. In fact, the giant river otter has gained the nickname "river wolf" because of its ability to catch fish with such skill, making it a top-ranking aquatic predator in its home range.

When not consuming fish, giant otters are snacking on other touch meals such as amphibians, snakes, and crustaceans. Their ability to eat these tougher foods is thanks in part to a specialized tooth in the back of their mouth found in all mustelids. These teeth run perpendicular to the other cheek teeth in the mouth and, when occluded, act like a pair of scissors to rip and tear tough food.

The waters found in the Amazon don't make for crystal clear hunting grounds. Waters are filled with sediments, and light may be drastically lessened by overhanging canopies. To combat this, otters have special hairs on their face called vibrissae. Also called whiskers, these hairs are highly sensitive to touch and movement, so otters are able to hone in on sensory information gathered from vibrissae to track down potential prey.

Giant otters have webbed feet and strong tails to help them catch fish.

A photograph of a giant otter eating fish.



Giant Otter Behavior

Giant otters are a favorite of zoo-goers across the globe because of their charismatic personalities. These aquatic mustelids are highly social and are seen grooming, playing, and snuggling with each other throughout most of the day. They are diurnal, meaning they are most active throughout the day. At night, they bed down with each other in dens or burrows.

Family groups may consist of anywhere from just a few individuals to up to ten. These groups are typically composed of a single mating pair and their young from multiple breeding seasons. When the young are old enough to find their own mates, they are excluded from the group and go off to form their own families. However, while growing and maturing, pups from previous generations assist in raising newer generations.

### Diet

Giant river otters are piscivores. This means that they eat a diet primarily composed of fish. A typical river otter may eat anywhere between six to nine pounds of fish every day. This diet is then supplemented with various other organisms encountered opportunistically including:

- Frogs
- Small mammals
- Crustaceans
- Snakes

### Social Interactions

As noted above, otters live in family groups and interact with each other often. These highly social creatures participate in multiple activities with each other. Groups may often be seen hunting together to increase the odds of catching a meal. They are also highly vocal with each other and make several distinctive sounds that all have different meanings. Social grooming is another common behavior.

In the wild, otters tend to be skittish of humans. However, it would not be unreasonable to see adult otters acting defensive of young or burrow sites. In captivity, otters are highly conditioned to people and often form personal relationships. Despite this, giant otters are still wild animals and should be handled with caution in captive settings to prevent injury to both animals and handlers.



Lesson Summary

Giant otters are large aquatic mammals that are native to the fresh-water wetlands of South America. Their scientific name is Pteronura brasiliensis and they are mustelids within the family Mustelidae. Mustelids are carnivorous mammals that include otters, weasels, otters, badgers, martens, and wolverines.

These river otters are well adapted to aquatic life for multiple reasons:

- They possess waterproof fur that stays warm and dries quickly
- They are excellent swimmers because of their strong rudder-like tails and webbed feet
- They can close their ears and nostrils while underwater

They are also able to quickly find food even in murky waters because of highly sensitive hairs on their face called vibrissae, or whiskers. Giant river otters are piscivores, meaning their diet consists of mostly fish supplemented with the occasional reptile, amphibian, or crustacean. They are diurnal, being most active at night, and are highly social living in moderate-sized family groups.

Unfortunately, due to habitat loss and conflict with people, giant river otters are considered endangered. Aquatic ecosystems are susceptible to chemical alteration by ash which reduces fish populations. Many acres of habitat are also converted into agricultural land each year. Fishermen who view otters as competition may also poach them to prevent reduced income.



## Additional Info

## What Are Giant Otters?

A family comes out of their home for an afternoon activity. Strolling from their dwelling down to the river, the parents supervise as older siblings play with the youngsters, frolicking in the water and on the banks. Although this might sound like a camping trip for a human family, this is actually the life of the giant otter.

Giant otters are mammals related to the weasel family. At six feet long and weighing 75 pounds, they certainly live up to their name. Like human families, these animals mate in monogamous pairs, living with large families in a gregarious lifestyle.

These beautiful creatures, covered in muscles coated with a dark brown fur are endangered due to habitat destruction and hunting. Today we're going to learn more about where they live, how their populations are changing and some cool facts about the giant otter.

## Habitat

The giant otter is native only to the Amazon, Orinoco, and La Plata river systems in South America. They dwell in flooded forests, slow moving rivers, streams, lakes and swamps. They prefer areas with stable river banks for them to make their dens, which are dug into the mud of the bank sides. Trees surround them in the tropical forest, providing shade in the heat of the midday sun.

A family of giant otters leaves the river for their den on the bank
otter family

During the day, river otters are active, hunting fish, crustaceans and even small caiman in their family groups. At night, they retreat back to their river bank den, getting some much needed rest after a day of swimming.

## Population

Although there is somewhat limited data about the exact number of giant otters in the wild, scientists agree that they are an endangered species, in danger of going extinct. Their numbers are currently declining, with no population recovery in sight.

Why are these fun loving creatures in such a bad situation? It turns out the thick, luscious fur that keeps them dry and warm has been a long coveted possession of humans. Up until the 1970's the giant otter was hunted for pelts used to make human coats, scarves and other cold weather apparel. The hunting decimated their populations.

However, today the giant otter faces different challenges with humans. First, giant otters are excellent hunters. They look for fish and other aquatic animals, hunting skillfully in groups. Unfortunately, humans are not quite as skilled at fishing and see giant otters as competition for valuable profits. Sometimes this can lead to fisherman killing the giant otters to ward off such competition.

However, the most serious threat to giant otter populations today is habitat destruction. Increasing populations and demand for land and natural resources are destroying the forests and rivers that the giant otters call home. When chunks of forest are clearcut away, their habitat becomes disrupted, causing habitat fragmentation. With such small numbers already, this is making it harder for the giant otter population to recover.

## Adaptations

Although giant otters are losing the battle in human conflict, they have evolved amazing adaptations to help them survive nature's challenges in the wild. The original reason for population decline was the otter's soft fur. Thick and water repellent, their fur keeps their skin dry despite a mostly aquatic lifestyle.

If you've ever been scuba diving or snorkeling, you know that donning a pair of large fins makes you swim far faster than your own feet, which are designed for land. Although giant otters don't have fins like a scuba diver or even fins like a fish, their four paws are webbed, creating a similar effect.

Webbed paws help giant otters swim
paws

Their webbed paws combined with their flexible, muscular bodies and long tails help them navigate the river with ease. When diving, their ears and nose close when they submerge underwater as well. If you've ever gotten a nose full of water in a swimming pool, you understand this is a very valuable adaptation!

As humans, we rely heavily on eyesight to get around in the world. However, otters have another important sensory organ at their disposal, called vibrissae. These whiskers are extremely sensitive and can detect small changes in current, allowing them to detect their prey without even seeing them. This can be helpful to outsmart fish equipped with camouflage to hide from predators.

## Behavior

Like humans, giant otters are quite gregarious. They live in monogamous pairs with several generations of family, sometimes with 20 individuals living together. The constant need for food requires the family to work together. A group of giant otters easily corners and captures fish. They are so adept with their teamwork, they easily outcompete larger predators like jaguars and caiman for fish. Each giant otter needs up to nine pounds of fish per day, so with twenty mouths to feed that's quite a lot of hunting!

Much of a giant otter
giant otter eating

## Lesson Summary

Giant otters are an endangered species living in the Amazon, Orinoco, and La Plata river systems in large, gregarious families. They have thick fur that caused them to be hunted to near extinction. Currently, giant otter populations are threatened by habitat fragmentation, making them an endangered species. In addition to their waterproof fur, giant otters also have webbed feet, long tails, nose and ear coverings for swimming, and vibrissae to detect prey.

### Register to view this lesson

Are you a student or a teacher?

I am a student
I am a teacher

### Unlock Your Education

#### See for yourself why 30 million people use Study.com

##### Become a Study.com member and start learning now.

Back

### Resources created by teachers for teachers

Over 30,000 video lessons
& teaching resources‐all
in one place.



Video lessons



Quizzes & Worksheets



Classroom Integration

![](/images/videoPaywall/paywallMango/lesson plan.svg)

Lesson Plans

I would definitely recommend Study.com to my colleagues. It’s like a teacher waved a magic wand and did the work for me. I feel like it’s a lifeline.

Jennifer B.

Teacher

Jennifer B.

Back

23 chapters |

302 lessons

Ch 1.

Order Diptera

Ch 2.

Orders Eulipotyphia, Chiroptera &...

Ch 3.

Extinct & Endangered Animals

Ch 4.

Aquatic & Semi-Aquatic Animals &...

Ch 5.

Order Sirenia

Ch 6.

Order Cetartiodactyla

Ch 7.
Order Carnivora

Ch 8.

Order Rodentia

Ch 9.

Order Monotremata

Ch 10.

Family Rhinocerotidae

Ch 11.

Class Arachnida

Ch 12.

Arboreal Animals

Ch 13.

Understanding Jellyfish

Ch 14.

Class Insecta

Ch 15.

Order Isopods

Ch 16.

Order Passeriformes

Ch 17.

Order Primates: Chimpanzees &...

Ch 18.

Order Primates: Gorillas &...

Ch 19.

Order Primates: Lemurs

Ch 20.

Order Primates: Lorises, Galagos, &...

Ch 21.

Order Primates: Macaques &...

Ch 22.

Order Primates: New World...

Ch 23.

Class Aves

#### Giant Otter | Habitat, Size & Adaptations Related Study Materials

##### Browse by Courses

##### Browse by Lessons

Create an account to start this course today

Used by over 30 million students worldwide

Like this lesson Share

#### Explore our library of over 88,000 lessons

Search

Browse

Browse by subject

Upgrade to enroll×

Upgrade to Premium to enroll in Kingdom Animalia: Study Guide & Review

Enrolling in a course lets you earn progress by passing quizzes and exams.

Track course progress

Take quizzes and exams

Earn certificates of completion

You will also be able to:

- Create a Goal
- Create custom courses
- Get your questions answered

Upgrade to Premium to add all these features to your account!

Upgrade to Premium to add all these features to your account!

#### Download the app

#### Plans

#### About Us

#### Support

#### Download the app

© Copyright 2024 Study.com.
All other trademarks and copyrights are the property of their respective owners.
All rights reserved.

×