Colombian Oldfield Mouse vs Laysan Duck

Thomasomys dispar compared with Anas laysanensis

Key Differences

• Colombian Oldfield Mouse is Data Deficient while Laysan Duck is Critically Endangered.

Taxonomic Classification

Rank	Colombian Oldfield Mouse	Laysan Duck
Kingdom same	Animalia (حيوانات)	Animalia (حيوانات)
Phylum same	Chordata (حبليات)	Chordata (حبليات)
Class	Mammalia (ثدييات)	Aves (طيور)
Order	Rodentia (قوارض)	Anseriformes (إوزيات)
Family	Cricetidae	Anatidae
Genus	Thomasomys	Anas
Species	Thomasomys dispar	Anas laysanensis

Evolutionary Relationship

Colombian Oldfield Mouse and Laysan Duck share a common ancestor at the Phylum level: Chordata. (حبليات)

Conservation Status

Colombian Oldfield Mouse

DD — Data Deficient

Laysan Duck

CR — Critically Endangered

Physical Characteristics

Attribute	Colombian Oldfield Mouse	Laysan Duck
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Colombian Oldfield Mouse

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Range

Found in Colombia.

Laysan Duck

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and Mediterranean forests and woodlands within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Belgium, France, Netherlands, Norway, and United Kingdom. Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Colombian Oldfield Mouse

<em>Thomasomys dispar</em>, commonly known as the Colombian Oldfield Mouse, is a small rodent species belonging to the genus <em>Thomasomys</em> within the family Cricetidae. This species is classified as Data Deficient, indicating that insufficient information is currently available to evaluate its conservation status with confidence. It has been documented in Colombia, where it inhabits diverse terrestrial and aquatic-adjacent environments. Members of the genus <em>Thomasomys</em> are typically associated with high-altitude Andean habitats, including páramo grasslands, shrublands, and montane forest edges, where they occupy ground-level microhabitats and burrow in soft soils. These mice are generally omnivorous, consuming seeds, plant material, and invertebrates, though specific dietary data for <em>Thomasomys dispar</em> have not been recorded. Biological traits of this species remain poorly documented in the scientific literature. The Data Deficient classification highlights the need for targeted surveys in Colombian Andean regions to determine population size, distribution, and the ecological requirements of this poorly known rodent.

Laysan Duck

Laysan Duck (Anas laysanensis) is classified as Critically Endangered (CR) on the IUCN Red List. Facing an extremely high risk of extinction in the wild due to severe population decline and habitat loss.