Canadian beaver vs Common Fat-tailed Mouse Opossum

Castor canadensis compared with Thylamys pusillus

Key Differences

• Canadian beaver is Not Evaluated while Common Fat-tailed Mouse Opossum is Least Concern.

Taxonomic Classification

Rank	Canadian beaver	Common Fat-tailed Mouse Opossum
Kingdom same	Animalia (hayvan)	Animalia (hayvan)
Phylum same	Chordata (Kordalılar)	Chordata (Kordalılar)
Class same	Mammalia (memeliler)	Mammalia (memeliler)
Order	Rodentia (kemiriciler)	Didelphimorphia (Didelphimorphia)
Family	Castoridae (Beavers)	Didelphidae
Genus	Castor (Beavers)	Thylamys
Species	Castor canadensis	Thylamys pusillus

Evolutionary Relationship

Canadian beaver and Common Fat-tailed Mouse Opossum share a common ancestor at the Class level: Mammalia. (memeliler)

Conservation Status

Canadian beaver

NE — Not Evaluated

Population: ~15.0M

Trend: Stable →

Common Fat-tailed Mouse Opossum

LC — Least Concern

Physical Characteristics

Attribute	Canadian beaver	Common Fat-tailed Mouse Opossum
Diet	Herbivore	—
Average Lifespan	15 years	—
Average Length	1.0 m	—
Average Weight	25.0 kg	—

Habitat & Geographic Range

Canadian beaver

Habitat

Typically found in grasslands, forests, and vegetated habitats.

Range

Widely distributed across Europe (15 countries), North America (United States), and South America (Argentina, Chile).

Common Fat-tailed Mouse Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Canadian beaver

The largest rodent in North America, Canadian beavers weigh up to 32 kg and are master ecosystem engineers inhabiting rivers, lakes, and wetlands across Canada and the northern United States. By felling trees and constructing dams up to hundreds of meters long, beavers create ponds that provide habitat for hundreds of species. Their lodges and canals transform entire watersheds. Once nearly hunted to extinction for their fur, beaver populations have recovered strongly.

Common Fat-tailed Mouse Opossum

The Common Fat-tailed Mouse Opossum (<em>Thylamys pusillus</em>) is a small marsupial belonging to the genus Thylamys within the family Didelphidae. Like other members of its genus, this species typically stores fat in its tail, which becomes swollen during periods of food abundance and is metabolised during leaner times, a physiological adaptation that provides energy reserves. <em>Thylamys pusillus</em> is generally found in diverse terrestrial and aquatic ecosystems, often in dry woodlands, scrublands, and grassland habitats of South America. The species is assessed as Least Concern on the IUCN Red List, indicating it is not currently considered at risk of extinction. Detailed geographic range data are not available in the current record, but members of this genus are typically distributed across parts of Argentina, Bolivia, Paraguay, and Uruguay. Biological traits including average lifespan, body dimensions, and specific dietary composition remain poorly documented in the scientific literature, though Thylamys species are generally considered omnivorous, often consuming insects, small vertebrates, and plant material.