| Key Differences | Muskrat | Beaver |
| Scientific classification | Class: Mammalia Order: Rodentia Family: Cricetidae Subfamily: Arvicolinae Tribe: Ondatrini Genus: Ondatra Species: Ondatra zibethicus | Class: Mammalia Order: Rodentia Family: Castoridae Subfamily: Castorinae Genus: Castor Species: C. canadensis, C. fiber |
| Size | 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) | Body Length: 29 to 35 inches (74 to 90 centimeters) Tail length: 9.8 to 11.8 inches (25 to 30 centimeters) Weight: 0.6–2 kilograms (1.3–4.4 pounds) |
| Appearance | – Almost triangularly shaped tail covered with scales – Ears slightly less visible than those of a nutria – Black whiskers | – have paddle-shaped tails – Ears slightly less visible than those of a nutria |
| Distribution | Native Range: North America Introduced: Eurasia, South America | Native Range: North America Introduced: Argentina, Finland, Belgium, Germany, the Russian Federation, and Luxembourg |
| Behavior | – Primarily nocturnal – Families formed by a male, a female, and their young | – excellent swimmers walk quite slowly on land – walk quite slowly on land, have a keen sense of smell |
| Diet | 96% herbivorous; 4% carnivorous | 96% herbivorous; 4% carnivorous |
| Predators | Coyotes, mink, cougar, birds of prey, snakes, alligators, bobcats | Bobcats, foxes, and Canada lynx |
| Reproduction | Gestation period: 25–30 days Litter capacity: 2-3 | Gestation period: 107–128 days Litter capacity: 1 |
| Lifespan | – 3 years in the wild – 10 years in captivity | – 10-15 years in the wild – 20 years in captivity |
Muskrats and beavers look incredibly alike! It’s almost impossible to distinguish them!
Luckily, we’ve discovered some key differences that will help you tell them apart in no time!
The most noticeable difference is the size; muskrats are much smaller than beavers.
Secondly, muskrats have long, thin tails, while beavers have flat, wide tails.
Are you curious to learn more? Keep reading!
You’re about to learn a myriad of details about these two rodents, starting with their scientific classification and ending with their ecological roles!
What Are the Major Differences Between Muskrats and Beavers?
As mentioned, muskrats and beavers look very similar.
If one doesn’t know what to look for, they will suspect the two rodents are the same species, especially if seen swimming!
But, as it turns out, these two rodents have evolved with distinctive feeding adaptations, behaviors, and growth stages.
Although they live in similar habitats, they impact them differently.
Since the most important difference between a muskrat and a beaver stand in their taxonomic classification, let’s start by discussing the families they’re part of!
Scientific Classification
| Key Differences | Nutria | Beaver |
| Scientific classification | Class: Mammalia Order: Rodentia Family: Echimyidae Subfamily: Echimyinae Tribe: Myocastorini Genus: Myocastor Species: Myocastor coypus | Class: Mammalia Order: Rodentia Family: Castoridae Subfamily: Castorinae Genus: Castor Species: C. canadensis, C. fiber |
While both are part of the Rodentia order, muskrats are classified under the Cricetidae family, while beavers are in the Castoridae family.
Muskrats are scientifically called Ondatra zibethicus. They are most closely related to voles and lemmings and are more distantly related to New World rats and mice.
In fact, their family consists of almost 608 species!
Specialists recognize 16 muskrat subspecies, classified depending on their geographic location.
Things are much easier in terms of taxonomic classification when it comes to beavers.
Their family, Castoridae, includes only beavers, of which the majority are extinct.
The only two extant species are grouped in the Castor genus – C. fiber (Eurasian beaver) and C. canadensis (North American beaver).
These two species are most closely related to the extinct C. californicus, which existed during the Late Miocene until the Early Pleistocene and lived in western North America.
Therefore, since there are two types of beavers, we’ll focus our discussion on comparing muskrats with both the Eurasian and the North American beaver forms.
Size
| Key Differences | Muskrat | Beaver |
| Size | 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) | Body Length: 29 to 35 inches (74 to 90 centimeters) Tail length: 9.8 to 11.8 inches (25 to 30 centimeters) Weight: 0.6–2 kilograms (1.3–4.4 pounds) |
Beavers are twice as big and ten times as heavy as muskrats!
Muskrats have a head-to-tail length of 40–70 centimeters (16–28 inches).
Half of this length is made up by the tail, so their bodies are actually quite small!
Muskrats are neither too heavy, as they weigh only 0.6–2 kilograms (1.3–4.4 pounds).
Beavers, on the other hand, are much bigger. The North American species is slightly smaller than the Eurasian species.
North American beavers have a head-to-tail length of 95–125 centimeters (37.4–49.2 inches) and weigh between 11–32 kilograms (24–70.5 pounds), although very old individuals can reach an exceptional weight of 40–50 kilograms (88–110 pounds)!
Eurasian beavers have a head-to-tail length of 105–150 centimeters (41.3–59 inches) and weigh 11–30 kilograms (24.3–66 pounds).
Like their North American relatives, they can become much heavier as they age.
Appearance
| Key Differences | Muskrat | Beaver |
| Appearance | – Almost triangularly shaped tail covered with scales – Ears slightly less visible than those of a nutria – Black whiskers | – have paddle-shaped tails – Ears slightly less visible than those of a nutria |
The easiest way to distinguish a muskrat from a beaver (besides the noticeable size!) is by checking the form of the tail.
Muskrats have long, thin tails that are only slightly flattened vertically.
In contrast, beavers have paddle-shaped tails. Can you imagine that a beaver’s tail can be 15 centimeters (6 inches) wide?
Additionally, a muskrat’s tail is almost hairless, while a beaver’s tail is covered in leathery scales.
Here are some other things to consider when comparing the two rodents:
- Both muskrats and beavers have large incisors, although their colors differ slightly. Muskrat incisors are yellow-orangish, while beaver incisors are orange to reddish-brown.
- A beaver’s ears are much more visible than a muskrat’s ears.
- A beaver’s fur is longer than a muskrat’s fur, but both have two-layered coats.
- Muskrats are typically dark brown to black, while beavers have a wider range of coat colors, starting with beige and ending with reddish brown and blackish.
- Both rodents have four limbs. Their front paws are clawed. The hindlimbs of a beaver are more webbed than the hindlimbs of a muskrat.
If you see one of them swimming, you may not be able to notice these differences from afar. So, here’s another tip to distinguish them!
If you spot a muskrat swimming, you should be able to see the whole body above the water, obviously without the limbs.
Beavers, on the other hand, usually keep only their heads above the water while swimming.
Habitat and Distribution
| Key Differences | Muskrat | Beaver |
| Distribution | Native Range: North America Introduced: Eurasia, South America | Native Range: North America Introduced: Argentina, Finland, Belgium, Germany, the Russian Federation, and Luxembourg |
Muskrats are native to Canada, the United States, and Mexico. Their natural range overlaps with the natural range of the North American beaver.
The Eurasian beaver is found only in Eurasia, just as its name implies.
Therefore, one may say that seeing a rodent that looks like a beaver or a muskrat in Europe makes the answer quite clear – it must automatically be a Eurasian beaver since muskrats and North American beavers don’t live there, right? Well, not so fast!
Muskrats have been introduced in different parts of the Eurasian continent and have even become invasive!
They’re found in Belarus, Austria, Belgium, Estonia, Finland, France, Moldova, the Netherlands, Romania, and other countries. They’ve also been introduced to Argentina and Chile.
The same goes for the North American beaver, as it’s an introduced species in Argentina, Finland, Belgium, Germany, the Russian Federation, and Luxembourg.
Since all three species are semi-aquatic, they’re found in similar habitats, which makes telling them apart even more difficult!
Muskrats, North American beavers, and Eurasian beavers live close to freshwater ecosystems like streams, rivers, ponds, and lakes surrounded by diverse vegetation.
Besides this, both muskrats and beavers can adapt well to living in brackish and saltwater habitats.
On the other hand, beavers seem to be slightly more adaptable than muskrats, as they’re known to survive in agricultural and urban areas, golf courses, the mountains, and even near shopping malls!
Behavior
| Key Differences | Muskrat | Beaver |
| Behavior | Primarily nocturnal Families formed by a male, a female, and their young | – excellent swimmers walk quite slowly on land – walk quite slowly on land, have a keen sense of smell |
Muskrats and beavers are excellent swimmers and walk quite slowly on land.
Additionally, both can remain underwater for roughly 15 minutes.
Unlike muskrats, which have poor eyesight, smell, and hearing, beavers have a keen sense of smell, which is used to inspect the surroundings.
Keep reading to learn some more behavioral differences between these two rodents!
Home Building and Territoriality
Beavers are renowned for being hard workers and building dams, whereas muskrats build push-ups from vegetation and mud.
Nevertheless, both rodents are excellent diggers. Beavers rely on their digging abilities to create burrows in a bank if they do not have the required materials to construct dams.
Muskrats rely on digging burrows into a bank if they live in streams, lakes, or ponds, as the push-ups are only built in marshes.
Naturally, beavers build much larger homes than muskrats, as they occupy much more space, given how big they are!
In terms of social structures and territoriality, muskrats and beavers are similar. Both rodents live in large families and are highly territorial.
The major difference is that muskrats are much more aggressive, even toward each other!
They may even kick their offspring out of their territories if they get too crowded!
Beavers, on the other hand, are more affectionate toward their own. But if another animal intrudes on their territories, they’ll fiercely defend them!
Daily Routine
Muskrats are primarily active at night, although some may prefer getting all those errands done near dawn or dusk. The same is true for North American and Eurasian beavers.
Although both rodents are active year-round, beavers have some unique adaptations you may have never heard about!
The populations living in northern latitudes literally change the length of their days!
Their 24-hour cycle becomes longer, lasting between 26 and 29 hours.
They spend more time in their lodges using their fat reserves and stored food, and in there, they cannot distinguish light levels and take notice of sunrises and sunsets.
Therefore, their circadian rhythm breaks down due to the lack of solar cues. Consequently, their days become longer!
Muskrats, on the other hand, do not store as much food in their push-ups and are more active when the weather is cold.
If they can’t go out, they may start feeding on the vegetation they used to build the push-ups.
If they do go out foraging, they have no trouble swimming. In fact, they can dive for 15 minutes in the cold winter water to gather food.
Muskrats can survive this adventure because their heart rate decreases, oxygen is provided by the muscle tissue stores, and the waterproof fur keeps them warm.
Additionally, their lips are sealed behind the incisors, so they do not even swallow water!
Although beavers can swim in the freezing winter water thanks to their adaptations, they do so much more rarely than muskrats.
Diet
| Key Differences | Muskrat | Beaver |
| Diet | 96% herbivorous; 4% carnivorous | 96% herbivorous; 4% carnivorous |
Muskrats and beavers are primarily herbivorous, although muskrats may occasionally delight in a carnivore meal, which typically includes mussels, fish, small turtles, frogs, and crayfish.
In contrast, beavers are pure vegetarians.
A muskrat’s diet is 95% plant-based. These rodents prefer various types of aquatic vegetation and may occasionally eat crops.
Beavers are generalist herbivores and eat leaves, herbs, ferns, grasses, water shields, cattails, and, in short, anything edible vegetation they stumble upon!
When the temperatures drop, their bark intake increases. Additionally, they start feeding more on birch, oak, dogwood, alder, and aspen.
Predators
| Key Differences | Muskrat | Beaver |
| Predators | Coyotes, mink, cougar, birds of prey, snakes, alligators, bobcats | Bobcats, foxes, and Canada lynx |
Considering their size, muskrats are more susceptible to predation than beavers.
Muskrats fall prey to mink, cougars, coyotes, wolverines, birds of prey, various snakes, alligators, bobcats, and other similar animals.
Young muskrats may even be predated by large fish, like largemouth bass, or reptiles, like monitor lizards!
In addition, various deer species feed on their push-ups in the winter, thus destroying their homes!
Conversely, beavers are much bigger and typically fall prey to coyotes, mountain lions, wolves, and bears.
Baby beavers may be hunted and killed by bobcats, foxes, and Canada lynx.
Despite this, both muskrats and beavers have excellent adaptations to escape predators, including the possibility of making themselves invisible by hiding in the water!
Reproduction and Life Cycle
| Key Differences | Muskrat | Beaver |
| Reproduction | Gestation period: 25–30 days Litter capacity: 2-3 | Gestation period: 107–128 days Litter capacity: 1 |
Muskrats and beavers are mammals, so they reproduce sexually. Still, their breeding seasons, gestation periods, and litter sizes vary.
Here are some key differences between muskrats and beavers regarding their reproductive behavior and life cycle:
- Muskrats breed between March and September, while beavers’ mate between January and February.
- A muskrat’s gestation period lasts 25–30 days, whereas a beaver’s gestation period lasts 107–128 days.
- Female muskrats have 2–3 litters a year. Beavers produce one litter yearly.
- Female muskrats give birth to 6–8 young, while beavers give birth to 2–6 young.
- Baby muskrats are born quite small, blind, and hairless, whereas newborn beavers are fully covered in hair and open their eyes a few days after birth. Muskrat kits open their eyes when they’re 12–20 days old.
- In muskrat kits, weaning occurs 3–4 weeks after birth, whereas beaver kits are weaned much later, approximately 10–12 weeks after birth, although they can eat solid food when they’re only two weeks old.
- Muskrats become sexually mature when they’re 9–10 months old, while beavers become sexually mature at 1.5–3 years of age.
- Muskrats have a life expectancy of only three years in the wild. In contrast, beavers can live up to ten years.
Ecological Role
The rodents we’re discussing today play significant roles in their ecosystems. Nevertheless, the way their presence impacts their respective habitats differs.
Muskrats represent an important food source for a myriad of predators, so they directly sustain the existence of other animals.
They also have an impact on the composition of the local plant community.
While beavers are also hunted by local predators, their roles as ecosystem engineers and keystone species give them the upper hand.
Considering that they are generalist feeders and excellent dam builders, it’s not surprising!
Additionally, beavers impact aquatic invertebrate communities by creating a favorable habitat that allows them to thrive.
Human Interaction
Muskrats have been long hunted for their fur and meat. Despite this, their species is still listed as Least Concern on the IUCN Red List.
Muskrats are even considered an invasive species in some regions, as their burrowing behavior increases the risk of flooding!
Besides this, some populations are known to eat corn and other crops that grow close to their habitats.
Additionally, muskrats are highly aggressive. They attack their own, so imagine how mad they’d be if they felt threatened by people!
They aren’t even afraid to attack much larger dogs! Muskrats are also carriers of various diseases and parasites, which can be transmitted through bites.
Like muskrats, beavers can damage crops, roads, gardens, and pastures. They can also become quite aggressive if threatened and may attack both humans and pets.
Beavers are extensively hunted and trapped for their meat and fur.
They have historically been hunted for their castoreum, which supposedly cured stomach problems, sciatica, epilepsy, and vertigo.
Native Americans used beaver bones to make tools.
Sources:
- https://en.wikipedia.org/wiki/Muskrat
- https://www.dec.ny.gov/animals/57561.html
- https://animaldiversity.org/accounts/Ondatra_zibethicus/
- https://www.wildlifeillinois.org/gallery/mammals/found-near-water/muskrat/
- https://northernwoodlands.org/outside_story/article/in_homes_on_ice_muskrats_endure_the_season
- https://www.iastatedigitalpress.com/plugins/books/16/format/153/download/
- https://en.wikipedia.org/wiki/Beaver
- https://en.wikipedia.org/wiki/North_American_beaver
- https://en.wikipedia.org/wiki/Eurasian_beaver
- https://nationalzoo.si.edu/animals/beaver
- https://www.iucnredlist.org/species/4007/197499749
- https://www.iucnredlist.org/species/15324/22344525
- https://northernwoodlands.org/outside_story/article/beavers-winter
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