Nutria vs. Muskrat: What’s the Difference?

Leave a comment / / Updated on: 22nd October 2023

Nutria vs. Muskrat

Key DifferencesNutriaMuskrat
Scientific classificationClass: Mammalia
Order: Rodentia
Family: Echimyidae
Subfamily: Echimyinae
Tribe: Myocastorini
Genus: Myocastor
Species: Myocastor coypus
Class: Mammalia
Order: Rodentia
Family: Cricetidae
Subfamily: Arvicolinae
Tribe: Ondatrini
Genus: Ondatra
Species: Ondatra zibethicus
SizeBody length: 40–60 centimeters (15.8–23.6 inches)
Tail length: 30–45 centimeters (11.8–17.7 inches)
Weight: 4.5–7 kilograms (10–15.4 pounds)
Body Length: 26-36 centimeters (10.2–14.2 inches)
Tail length: 20–28 centimeters (7.9–11 inches)
Weight: 0.6–2 kilograms (1.3–4.4 pounds)
Appearance– Rounded, finely haired tail
– Distinctive white patch on the muzzle
– White whiskers
– Shorter fur
– Almost triangularly shaped tail covered with scales
– Ears slightly less visible than those of a nutria
– Black whiskers
DistributionNative range: South America
Introduced: all continents except Australia and Antarctica
Native Range: North America
Introduced: Eurasia, South America
Behavior– Primarily crepuscular; peak activity at midnight
– Families formed by a male, 3–4 females, and their young
– Primarily nocturnal
– Families formed by a male, a female, and their young
DietHerbivorous; occasionally ingests crustaceans96% herbivorous; 4% carnivorous
PredatorsAlligators, eagles, snakes, turtles, dogs, birds of preyCoyotes, mink, cougar, birds of prey, snakes, alligators, bobcats
ReproductionGestation period: 130 days
Litter capacity: 1–13
Gestation period: 25–30 days
Litter capacity: 1–8
Lifespan– 3 years in the wild
– 6 years in captivity
– 3 years in the wild
– 10 years in captivity

Nutria and muskrats are almost indistinguishable! They even share the same habitats! How can we tell them apart if they share so many physical and behavioral traits? 

If we don’t know the specifics, it’s impossible to understand which is which.

Luckily, we’ve found some major differences between these two rodents and are about to share them with you!

What Are the Major Differences Between Nutria and Muskrats?

Before diving into details, here are some key differences between a nutria and a muskrat:

  • Nutria are larger than muskrats.
  • Nutria have more rounded tails, while muskrats have slightly flattened tails.
  • Nutria have white fur on their muzzles and white whiskers, whereas muskrats have black whiskers.

Are you eager to discover more dissimilarities between these two large rodents? Keep reading; we’ve got plenty!

Scientific Classification

Key DifferencesNutriaMuskrat
Scientific classificationClass: Mammalia
Order: Rodentia
Family: Echimyidae
Subfamily: Echimyinae
Tribe: Myocastorini
Genus: Myocastor
Species: Myocastor coypus
Class: Mammalia
Order: Rodentia
Family: Cricetidae
Subfamily: Arvicolinae
Tribe: Ondatrini
Genus: Ondatra
Species: Ondatra zibethicus
Nutria vs. Muskrat
Rodent family | GlobalP via iStock

Nutria and muskrats are rodents, so they’re part of the Rodentia order. However, their similarities in terms of taxonomic classification end here.

Nutria are classified under the Echimyidae family of neotropical spiny rats and are close relatives of armored rats and painted tree rats.

In contrast, muskrats are in the Cricetidae family of large rodents, which includes voles, lemmings, true hamsters, and other species.

As such, nutria are scientifically called Myocastor coypus, as they’re part of the Myocastor genus, while muskrats are called Ondatra zibethicus and form the Ondatra genus.

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Size

Key DifferencesNutriaMuskrat
SizeBody length: 40–60 centimeters (15.8–23.6 inches)
Tail length: 30–45 centimeters (11.8–17.7 inches)
Weight: 4.5–7 kilograms (10–15.4 pounds)
Body Length: 26-36 centimeters (10.2–14.2 inches)
Tail length: 20–28 centimeters (7.9–11 inches)
Weight: 0.6–2 kilograms (1.3–4.4 pounds)
Nutria vs. Muskrat
Nutria with orange teeth coming out of river | RinoCdZ via iStock

Nutria are much larger than muskrats.

They have a body length of 40–60 centimeters (15.8–23.6 inches). Their long tails, however, add another 30–45 centimeters (11.8–17.7 inches) to the body length, making them appear larger. 

Their average weight ranges between 4.5–7 kilograms (10–15.4 pounds). Nonetheless, some individuals grew so large and heavy that they weighed 17 kilograms (37.5 pounds)!

Nutria vs. Muskrat
Close up cute furry muskrat on lawn eating grass one blade at a time

Muskrats, on the other hand, are tiny compared to nutria. They measure only 40–70 centimeters (15.8–27.5 inches) from the head to the tail. 

Imagine that half of this length is the tail, so their bodies are actually quite small! 

Muskrats are also much lighter than nutria, as they rarely grow heavier than 2 kilograms (4.4 pounds).

Appearance

Key DifferencesNutriaMuskrat
Appearance– Rounded, finely haired tail
– Distinctive white patch on the muzzle
– White whiskers
– Shorter fur
– Almost triangularly shaped tail covered with scales
– Ears slightly less visible than those of a nutria
– Black whiskers

Distinguishing a nutria from a muskrat is an arduous task for the untrained eye. 

However, we can share a tip you can undoubtedly rely on – unlike muskrats, nutria have a distinctive white fur patch on their muzzles. 

Nutria vs. Muskrat
Nutria’s white whiskers | mauribo via iStock

Additionally, while their whiskers are white, muskrat whiskers are black. 

As such, if you can see their faces, it’s easy to spot these differences! If you can’t… Things become more complicated.

First, you can try assessing their tails. A nutria’s tail is finely haired and more rounded than a muskrat’s tail, which is slightly flattened on the sides, almost forming a triangular shape, and covered with scales.

Nutria vs. Muskrat
A closeup of a Muskrat’s long fur | Wirestock via iStock

The next step is to pay attention to their fur. A muskrat’s fur is typically longer (the guard hairs can grow up to 7.6 centimeters (3 inches) long) than a muskrat’s fur; the former has a three-layered coat, while the latter has a two-layered coat.

Although both rodents have dark brown to black fur, muskrats have lighter undersides, which become gray as they age.

Apart from these aspects, little else can help you tell the two apart: their heads are large, their bodies are stocky, their ear, eye, and nostril arrangement is similar, their legs are quite small, and their hind feet are partially webbed.

Habitat and Distribution

Key DifferencesNutriaMuskrat
DistributionNative range: South America
Introduced: all continents except Australia and Antarctica
Native Range: North America
Introduced: Eurasia, South America
Nutria’s are native to North America | Danica Jovanov via iStock

Nutria are native to South America, and muskrats are native to North America. However, both species have been introduced to other parts of the world.

Nowadays, nutria live on every continent except Australia and Antarctica. 

Regardless, considering that they come from subtropical and temperate regions, many populations outside their native range become regionally extinct, especially those living in areas with cold winters.

Muskrats have a much more limited non-native distribution. They’re found only in Eurasia, Argentina, and Chile.

Nutria’s distribution expanded outside their native range in 1899 when they were first introduced to California in the United States. 

Muskrats were brought to Europe only a few years later, at the beginning of the 20th century.

As for their habitat, there are no major differences we can mention. Both rodents live in freshwater wetlands and marshes. 

However, it seems that nutria are slightly more adaptable, as they’re often spotted in urban areas, farm ponds, golf courses, and overgrown lots.

Still, we must admit that muskrats can also thrive in altered environments. They adapt well to streams containing sulfurous water drained from coal mines. 

While other aquatic and semi-aquatic creatures die in these habitats, muskrats declare the territories their own!

Behavior

Key DifferencesNutriaMuskrat
Behavior– Primarily crepuscular; peak activity at midnight
– Families formed by a male, 3–4 females, and their young
– Primarily nocturnal
– Families formed by a male, a female, and their young

Although they’re well adapted for moving on land, both nutria and muskrats are excellent swimmers thanks to their partially webbed feet. 

In short, they prefer swimming rather than walking, so much of their resting time is spent in the water. Additionally, this advantage helps them easily escape from predators.

One big difference between these rodents is that muskrats can stay submerged much longer than nutria. 

The latter can resist for only five minutes, while the former can survive 15 minutes under the water!

Nutria vs. Muskrat
Muskrat swiming at the surface of the lake water | Dmitry Potashkin via iStock

Another thing these two rodents have in common is that they’re not day foragers. 

Muskrats are thought to be primarily nocturnal, whereas nutria are primarily crepuscular. 

Even though the peak of a nutria’s activity is around midnight, they’ll relax until sunrise, when muskrats may go foraging for several more hours.

On the other hand, if food is scarce, nutria and muskrats go the extra mile and spend a few hours foraging during the day.

Muskrats living in marshes build so-called push-ups by using vegetation and mud, which, in the winter, have their entrances plugged with vegetation. 

In other habitats, like streams or lakes, they dig burrows into the bank and construct tunnels underwater. 

The long stretch of a river | Anastasiia Shavshyna via iStock

They can also build complex channels through the surrounding vegetation.

Nutrias have similar home-building behaviors. They live either in burrows or impartially underwater dens. 

One thing that can help you distinguish their homes is the material they’re made of – nutria uses mud and sticks (instead of vegetation) to create their lodges.

Besides this, nutria often occupy uninhabited burrows. They can even kick muskrats out of their burrows and claim them as their own!

Whereas a muskrat family consists of a male, a female, and their young, a nutria family is formed by a male, 3–4 females, and their offspring.

Nutria vs. Muskrat
Muskrat and his friend | Brian Woolman via iStock

Both rodents are highly aggressive and territorial, although muskrats are probably worse from this point of view, as they can even threaten their own!

When the weather gets cold, muskrats and nutria spend more time inside their homes but go out when possible to forage.

Neither species hibernates; they just spend more time sleeping during the winter. 

One difference between them from this point of view is their migratory behavior; muskrats do not migrate, while nutria often migrate when there’s an increased demand for food.

Diet

Key DifferencesNutriaMuskrat
DietHerbivorous; occasionally ingests crustaceans96% herbivorous; 4% carnivorous
Nutria vs. Muskrat
Muskrat having a little snack | BirdImages via iStock

Nutria and muskrats are herbivores that feed on aquatic vegetation. 

However, there’s something they do not have in common in terms of diet – muskrats may occasionally supplement their diets with mussels, frogs, small turtles, and fish.

This carnivorous intake depends on where muskrats live; populations inhabiting marshes feed primarily on plants like cattails, while those living in lakes or ponds become partially carnivorous.

By contrast, nutria feed only on plants like cattail, reeds, arrowheads, and others and usually consume whole plants, including the roots, rhizomes, and tubers. 

In the winter, they also feed on bark. They don’t mind if they accidentally ingest some crustaceans!

Predators

Key DifferencesNutriaMuskrat
PredatorsAlligators, eagles, snakes, turtles, dogs, birds of preyCoyotes, mink, cougar, birds of prey, snakes, alligators, bobcats

Besides being trapped and hunted by people and killed or injured in automobile collisions, nutria and muskrats have multiple natural predators.

American Alligator Swimming in Everglades | Mark Kostich via iStock

Nutria are preyed upon by alligators, birds of prey, turtles, and dogs. 

Raccoons and mink typically kill muskrats. They also fall prey to coyotes, foxes, owls, birds of prey, alligators, snakes, and bears.

Muskrats rely primarily on concealment to defend themselves from predators, as their sight, smell, and hearing are poor. 

Nutria, on the other hand, hear quite well and are always on the lookout for weird noises. Their eyesight and smell, however, are also poorly developed.

As mentioned, the most efficient way muskrats and nutria can flee from predators is to risk everything and run as fast as possible toward the water! 

In this situation, muskrats have the upper hand, as they can remain submerged for longer.

Reproduction and Life Cycle

Key DifferencesNutriaMuskrat
ReproductionGestation period: 130 days
Litter capacity: 1–13
Gestation period: 25–30 days
Litter capacity: 1–8

Nutria and muskrats are rodents and, therefore, mammals. Like most mammals, they reproduce sexually and give birth to live young. 

Nutria vs. Muskrat
The usual large nutria is located near the water because it is mating season | Kirdan via iStock

Nutria does not have a well-defined breeding season. They mate year-round throughout their range. 

Their breeding season peaks in October, February, or March. Conversely, muskrats breed only from March or April until September.

Once fertilization occurs, nutria undergo a gestation period of 130 days – much longer than muskrats, which give birth only 25–30 days after mating.

While nutria have a litter capacity of 13 young, they usually give birth to 4–5 babies. Muskrats give birth to 4–8 kits. Both rodents produce 2–3 litters a year.

Baby nutria are highly precocial, meaning they’re born quite developed – their bodies are completely covered in hair, their eyes are open, and they can start eating vegetation within hours after birth. 

Small nutria
The owner is holding a small nutia | StockSeller_ukr via iStock

They can even swim on the same day! Nutria starts reproducing when they are four months old.

Things are much slower with muskrat kits. They’re tiny, hairless, and blind at birth. 

They open their eyes only when they’re roughly 15 days old, which is also when they first attempt to swim. 

They are weaned 3–4 weeks after birth. Muskrats mature sexually at 9–10 months of age.

Things aren’t too encouraging in terms of life expectancy, as both nutria and muskrats live only three years in the wild.

On the other hand, life in captivity is much better for these species, as they enjoy a much longer life (6 years for nutria and 10 for muskrats).

Human Interaction and Ecological Roles

nutria
Gotcha little Nutria | Sonsedska via iStock

Although both rodents have been and still are trapped for meat and fur, they continue to thrive, and their populations expand, primarily thanks to their rapid reproduction rate and high adaptability. 

The species are currently listed as Least Concern on the IUCN Red List.

However, people aren’t too happy about their abundance, as their digging behaviors have caused major ecological problems.

Muskrats, for example, damage crops and water control systems. 

Nutria vs. Muskrat
Nutria swimming and eating a little branch in a pond | Fabiano Cattoi via iStock

In Europe, some muskrat populations are considered invasive due to their burrowing behavior, which causes damage to levees and dikes. 

These are essential to avoid flooding in countries like the Netherlands and Belgium.

Nonetheless, muskrats also have a positive ecological role. 

During the winter, for example, turtles may use muskrat houses as shelters, whereas mallards rely on building their nests on top of muskrat huts during the nesting season. 

Nutria vs. Muskrat
Be careful for predators little muskrat | Wirestock via iStock

Additionally, muskrats serve as prey for a myriad of animals, thus ensuring their survival.

Since nutria feed on whole plants, the damage they cause is much more extensive, as they are capable of destroying native plant communities and damaging the soil structure.

They settle in marshlands, destroy the vegetation, cause severe soil erosion, and leave only open waters behind, thus increasing the risk of extinction for other wildlife species relying on these environments.

In areas where people tried to regrow vegetation using fertilizers, the result was even worse because nutria became even more common in those areas, and, therefore, there was no chance of plant regrowth. 

Nutria can also lead to some plants’ extinction. In Louisiana, for example, these rodents eat seedling bald cypress. 

Specialists say that without any measures, the plant species may not survive the damage.

Nutria are known to cause severe damage to crops, especially in the United States. They destroy rice, corn, sugar, alfalfa, barley, oats, and various vegetables.

Diseases

nematode
Parasitic nematode | Grafissimo via iStock

The quality of life of nutria and muskrats is highly affected by the parasites they serve as hosts for and the diseases they carry and transmit to humans, pets, and livestock if the necessary transmission conditions are met.

Nutria and muskrats are parasitized by nematode parasites, tapeworms, blood flukes, liver flukes, ticks, fleas, and chewing lice.

Nutria are carriers of the following conditions that they can transmit to people, pets, and livestock:

  • Salmonellosis
  • Chlamydia psittaci
  • Encephalomyocarditis virus
  • Aeromonas spp. (bacteria associated with multiple human diseases)
  • Antibiotic-resistant bacteria
  • Septicemia
  • Toxoplasmosis
  • Rickettsiosis
  • Rabies

Of all the diseases muskrats carry and transmit, tularemia is the most dangerous. 

It’s spread through contaminated water, causes flu-like symptoms, and can be life-threatening to humans.

Check the list below for other diseases muskrats are reservoirs for:

  • Leptospirosis
  • Hemorrhagic disease
  • Pseudotuberculosis
  • Ringworm disease
  • Salmonellosis

FAQs

Are nutria the same as rats?

The term rat typically refers to the members of the Rattus genus and several other genera in the Rodentia order

Nutria, on the other hand, are part of the Myocastor genus and are often called coypu. As such, nutria are not the same as rats, but both are rodents.

Is a muskrat a beaver?

Muskrats and beavers are different rodents classified in different families under the Rodentia order.

Beavers are twice as large as muskrats. They also have paddle-shaped tails, while muskrats have thinner, slightly flattened tails.

Is it a rat or a muskrat?

Muskrats are typically larger than rats, have thicker, longer tails, and a stockier body shape. 

Additionally, rats are gray or black, whereas muskrats are usually dark brown and lighter on the undersides.

Is a water rat the same as a muskrat?

Although some water rats, like the Florida water rat, are commonly called muskrats, they are different rodents. 

Water rats are usually smaller than muskrats and have hairy tails. The Florida water rat, also called the round-tailed muskrat, is a close relative of the muskrat, as both are part of the Ondatrini tribe.

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