A water rat refers to any of 18 species of amphibious, carnivorous rodents . They are adapted to hunt in the water and to burrow along the edges of bodies of water, such as streams, rivers and lakes. Water rats have small eyes, nostrils that can close to keep water out, and small furry ears or no external ears. Their long, thick fur is dense, woolly, water-repellent, and typically gray or brown. Their tails are usually densely haired, and their long, wide hindfeet have stiff hair fringes and conspicuous webbing between the digits. They use their sensitive whiskers to locate prey underwater. Though most are nocturnal, some species are active during the day.

Where do water rats live?

Water rats are amphibious rodents that live near bodies of water. The genus Hydromys can be found in the mountains and coastal lowlands of Australia, New Guinea, and nearby islands, while the earless water rat ( Crossomys moncktoni ) lives in the mountains of eastern New Guinea. The African water rat ( Colomys goslingi ) lives along streams bordered by tropical forests. In the Western Hemisphere, 11 species of water rats live along streams in rainforests from southern Mexico into South America. These animals have adaptations like small eyes, closable nostrils, and water-repellent fur that help them thrive in their environments. They use sensitive whiskers to locate prey underwater, and their diet consists primarily of aquatic insects, crustaceans, and occasionally small fish.

What does a water rat look like?

Water rats are amphibious, carnivorous rodents, numbering 18 species, with physical adaptations for hunting in water and burrowing near water bodies. They have small eyes, nostrils that can close, and small or absent external ears. Their fleshy, blunt muzzles feature abundant, highly sensitive whiskers. Water rats have long, thick fur that is dense, woolly, water-repellent, and typically gray or brown. Their tails are usually densely haired, sometimes with a keel. Their long, wide hindfeet have stiff hairs and bald soles with webbing between the digits. The South American fish-eating rat is among the smallest species, while the Australian golden-bellied water rat is the largest.

How do water rats survive in aquatic habitats?

Water rats, also known as amphibious carnivorous rodents, have several adaptations that allow them to thrive in aquatic habitats. They possess small eyes, nostrils that can be closed to keep water out, and small or absent external ears. Sensitive whiskers on their blunt muzzle help them locate prey underwater by touch. Their long, thick fur is dense, woolly, water-repellent, and typically gray or brown. The tail is usually densely haired, sometimes with a keel along the underside. Water rats have long, wide hindfeet fringed with stiff hairs and bald soles with conspicuous webbing between the digits, aiding in swimming. These rodents can be found in various freshwater habitats, including lakes, rivers, and coastal mangrove swamps, and some species tolerate polluted waters. They are typically adept swimmers and aggressive underwater predators, consuming aquatic insects, crustaceans, and occasionally small fish.

What do water rats eat?

Water rats are amphibious rodents that are part of the mouse family, Muridae. They are carnivores that exhibit adaptations for hunting in water, such as small eyes, closable nostrils, small furry ears, sensitive whiskers, and water-repellent fur. Their diet consists primarily of aquatic insects, crustaceans, and occasionally small fish. For example, the golden-bellied water rat (Hydromys chrysogaster) eats invertebrates like aquatic insects, snails, mussels, crabs, and crayfish. They also consume vertebrates, including fish, frogs, turtles, birds, bird eggs, bats, and mice. Most water rats hunt underwater using their sensitive whiskers to locate prey, while the African water rat (Colomys goslingi) wades in shallow water to eat aquatic and terrestrial insects and snails.

What role do water rats play in their ecosystems?

Water rats, also known as amphibious carnivorous rodents, play diverse roles in their respective ecosystems. They are predators of aquatic invertebrates, such as insects, snails, mussels, crabs, and crayfish. Some species also consume vertebrates, including fish, frogs, turtles, birds, bats, and mice. Water rats are prey for larger animals. They are also important in the food chain as they consume insects and help control their populations. Additionally, water rats can be indicators of water quality, as they require clear, unpolluted freshwater streams in most cases. The golden-bellied water rat , for example, is tolerant of polluted aquatic habitats.

water rat

References & Edit History Related Topics

Quick Facts

Related Topics:: Hydromys; golden-bellied water rat; African water rat; European water vole; earless water rat

See all related content

water rat

rodent

Written and fact-checked by

Britannica Editors

History

Top Questions

What is a water rat?
A water rat refers to any of 18 species of amphibious, carnivorous rodents. They are adapted to hunt in the water and to burrow along the edges of bodies of water, such as streams, rivers and lakes.

Water rats have small eyes, nostrils that can close to keep water out, and small furry ears or no external ears. Their long, thick fur is dense, woolly, water-repellent, and typically gray or brown. Their tails are usually densely haired, and their long, wide hindfeet have stiff hair fringes and conspicuous webbing between the digits.

They use their sensitive whiskers to locate prey underwater. Though most are nocturnal, some species are active during the day.
1 Britannica Source
1. water rat
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Where do water rats live?
Water rats are amphibious rodents that live near bodies of water. The genus Hydromys can be found in the mountains and coastal lowlands of Australia, New Guinea, and nearby islands, while the earless water rat (Crossomys moncktoni) lives in the mountains of eastern New Guinea. The African water rat (Colomys goslingi) lives along streams bordered by tropical forests. In the Western Hemisphere, 11 species of water rats live along streams in rainforests from southern Mexico into South America.

These animals have adaptations like small eyes, closable nostrils, and water-repellent fur that help them thrive in their environments. They use sensitive whiskers to locate prey underwater, and their diet consists primarily of aquatic insects, crustaceans, and occasionally small fish.
1 Britannica Source
1. water rat
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What does a water rat look like?
Water rats are amphibious, carnivorous rodents, numbering 18 species, with physical adaptations for hunting in water and burrowing near water bodies. They have small eyes, nostrils that can close, and small or absent external ears. Their fleshy, blunt muzzles feature abundant, highly sensitive whiskers. Water rats have long, thick fur that is dense, woolly, water-repellent, and typically gray or brown.

Their tails are usually densely haired, sometimes with a keel. Their long, wide hindfeet have stiff hairs and bald soles with webbing between the digits.

The South American fish-eating rat is among the smallest species, while the Australian golden-bellied water rat is the largest.
1 Britannica Source
1. water rat
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How do water rats survive in aquatic habitats?
Water rats, also known as amphibious carnivorous rodents, have several adaptations that allow them to thrive in aquatic habitats. They possess small eyes, nostrils that can be closed to keep water out, and small or absent external ears. Sensitive whiskers on their blunt muzzle help them locate prey underwater by touch.

Their long, thick fur is dense, woolly, water-repellent, and typically gray or brown. The tail is usually densely haired, sometimes with a keel along the underside. Water rats have long, wide hindfeet fringed with stiff hairs and bald soles with conspicuous webbing between the digits, aiding in swimming.

These rodents can be found in various freshwater habitats, including lakes, rivers, and coastal mangrove swamps, and some species tolerate polluted waters. They are typically adept swimmers and aggressive underwater predators, consuming aquatic insects, crustaceans, and occasionally small fish.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What do water rats eat?
Water rats are amphibious rodents that are part of the mouse family, Muridae. They are carnivores that exhibit adaptations for hunting in water, such as small eyes, closable nostrils, small furry ears, sensitive whiskers, and water-repellent fur.

Their diet consists primarily of aquatic insects, crustaceans, and occasionally small fish. For example, the golden-bellied water rat (Hydromys chrysogaster) eats invertebrates like aquatic insects, snails, mussels, crabs, and crayfish. They also consume vertebrates, including fish, frogs, turtles, birds, bird eggs, bats, and mice. Most water rats hunt underwater using their sensitive whiskers to locate prey, while the African water rat (Colomys goslingi) wades in shallow water to eat aquatic and terrestrial insects and snails.
1 Britannica Source
1. water rat: Natural history
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What role do water rats play in their ecosystems?
Water rats, also known as amphibious carnivorous rodents, play diverse roles in their respective ecosystems. They are predators of aquatic invertebrates, such as insects, snails, mussels, crabs, and crayfish. Some species also consume vertebrates, including fish, frogs, turtles, birds, bats, and mice.

Water rats are prey for larger animals. They are also important in the food chain as they consume insects and help control their populations. Additionally, water rats can be indicators of water quality, as they require clear, unpolluted freshwater streams in most cases. The golden-bellied water rat, for example, is tolerant of polluted aquatic habitats.
1 Britannica Source
1. water rat
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

water rat, any of 18 species of amphibious carnivorous rodents. They exhibit many adaptations associated with hunting in water for food and burrowing along streams, rivers, and lakes. The eyes are small, the nostrils can be closed to keep water out, and the external portion of the ears is either small and furry or absent. Highly sensitive whiskers are abundant on the fleshy blunt muzzle. The long thick fur is gray or brown, dense and woolly, and water-repellent. The tail is usually densely haired, and in some species the hairs form a keel along the underside. The rats’ long, wide hindfeet are fringed with stiff hairs and have bald soles with conspicuous webbing between the digits.

Natural history

One of the smallest species is a South American fish-eating rat (Neusticomys monticolus) with a body length of 10 to 12 cm (4 to nearly 5 inches) and a tail of about the same length. The golden-bellied water rat (Hydromys chrysogaster) of Australia and New Guinea is the largest, with a body 20 to 39 cm long and a slightly shorter tail (20 to 33 cm). Living by freshwater lakes, estuaries, and rivers and in coastal mangrove swamps, it is tolerant of heavily polluted aquatic habitats. Its prey includes a variety of invertebrates, such as large aquatic insects, snails, mussels, crabs, and crayfish. Vertebrates taken include fish, frogs, turtles, young and adult birds, bird eggs, bats, and mice. The other 17 species typically require clear, unpolluted freshwater streams. The animals’ diet consists primarily of a variety of aquatic insects, but they also eat crustaceans and occasionally small fish. All water rats locate prey underwater by touch with their sensitive whiskers. Most are adept swimmers and aggressive underwater predators, but the African water rat (Colomys goslingi) wades through shallow water or sits at the water’s edge with its muzzle submerged; it is reported to eat some terrestrial insects and snails. Although most water rats are nocturnal, some species are active during the day.

Water rats of the genus Hydromys live in the mountains and coastal lowlands of Australia, New Guinea, and some nearby islands. The earless water rat (Crossomys moncktoni) inhabits mountains of eastern New Guinea, where it prefers cold, fast-flowing streams bordered by tropical forest or grass. The African water rat is also found along streams bordered by tropical forest. The 11 water rats of the Western Hemisphere are found from southern Mexico into South America, where they typically live along streams in rainforests from sea level upward to mountain pastures above the tree line.

Britannica Quiz

Match the Baby Animal to Its Mama Quiz

Classification

Although all water rats are members of the mouse family (Muridae), they belong to two different subfamilies. The genera Hydromys, Crossomys, and Colomys are classified in the subfamily Murinae (Old World mice and rats), whereas the American species are members of the subfamily Sigmodontinae (New World mice and rats). No water rats exist in the Asian tropics or at nontropical latitudes. Instead, carnivorous amphibious shrews and moles occupy the water rat’s ecological niche. The European water voles (genus Arvicola) are sometimes called water rats.

Genus Hydromys (water rat)
5 species.
Genus Neusticomys (neotropical, or fish-eating, rats)
5 species.
Genus Ichthyomys (crab-eating water rats)
3 species.
Genus Chibchanomys (Chibchan water mice)
2 species.
Genus Crossomys (earless water rat)
1 species.
Genus Colomys (African water rat)
1 species.
Genus Anotomys (Ecuador fish-eating rat)
1 species.

water rat

Natural history

Thank you for signing up!

Classification