Common Eastern Wildrye vs Common Fat-tailed Mouse Opossum

Elymus virginicus compared with Thylamys pusillus

Key Differences

• Common Eastern Wildrye is Not Evaluated while Common Fat-tailed Mouse Opossum is Least Concern.

Taxonomic Classification

Rank	Common Eastern Wildrye	Common Fat-tailed Mouse Opossum
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Chordata (Chordates)
Class	Liliopsida (Monocots)	Mammalia (Mammals)
Order	Poales (Grasses)	Didelphimorphia (Didelphimorphia)
Family	Poaceae (Grass Family)	Didelphidae
Genus	Elymus	Thylamys
Species	Elymus virginicus	Thylamys pusillus

Conservation Status

Common Eastern Wildrye

NE — Not Evaluated

Common Fat-tailed Mouse Opossum

LC — Least Concern

Physical Characteristics

Attribute	Common Eastern Wildrye	Common Fat-tailed Mouse Opossum
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Eastern Wildrye

Habitat

Typically found in grasslands, wetlands, forests, and cultivated landscapes.

Range

Distributed across Denmark, Sweden, and United States.

Common Fat-tailed Mouse Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Common Eastern Wildrye

<em>Elymus virginicus</em>, the common eastern wildrye, is a native North American grass in the family Poaceae, currently not evaluated by the IUCN Red List. The species is documented in Denmark, Sweden, and the United States, and typically inhabits grasslands, wetlands, forests, and cultivated lands across its range in eastern and central North America. It is a cool-season, perennial bunchgrass that typically grows in moist to mesic habitats including riverbanks, floodplain woodlands, forest understories, and moist prairies. <em>Elymus virginicus</em> is recognized by its distinctive nodding seed heads with stiff, curved awns and is among the most widely distributed wild rye grasses in North America. The species provides important ecosystem services as a native ground cover, stabilizing streambanks and riparian soils against erosion, and offering habitat and food resources for grassland birds, small mammals, and invertebrates. Common eastern wildrye is also valued in ecological restoration projects for its adaptability to a range of soil conditions and its ability to establish quickly in disturbed habitats. As a forage grass, it is moderately palatable to livestock and wildlife. Biological traits of this species remain poorly documented in the scientific literature.

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.