Brown Rat vs

Rattus norvegicus compared with Chroococcus minutus

Key Differences

• Brown Rat is Least Concern while is Not Evaluated.

Taxonomic Classification

Rank	Brown Rat
Kingdom	Animalia (Animals)	Bacteria (Bacteria)
Phylum	Chordata (Chordates)	Cyanobacteria (Cyanobacteria)
Class	Mammalia (Mammals)	Cyanobacteriia
Order	Rodentia (Rodents)	Cyanobacteriales
Family	Muridae (Mice & Rats)	Microcystaceae
Genus	Rattus	Chroococcus
Species	Rattus norvegicus	Chroococcus minutus

Conservation Status

Brown Rat

LC — Least Concern

NE — Not Evaluated

Physical Characteristics

Attribute	Brown Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brown Rat

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 10 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (11 countries), Asia (15 countries), Europe (41 countries), North America (16 countries), Oceania and the Pacific (10 countries), and South America (10 countries).

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, and Sweden.

Brown Rat

Brown Rat (Rattus norvegicus) is classified as Least Concern (LC) on the IUCN Red List. Widespread and abundant across its range, with stable populations and no immediate conservation concerns.

Chroococcus minutus is a cyanobacterium in the family Chroococcaceae, recognized as one of the smaller species in the genus. It is distributed in freshwater habitats across temperate regions, including Scandinavia and northern Europe, where it has been documented in taxonomic surveys of freshwater algae and cyanobacteria. Chroococcus species in general are characterized by their simple morphology — spherical or hemispherical cells, binary fission, and organization into pairs or tetrads within gelatinous sheaths. Chroococcus minutus occurs in the plankton and periphyton of lakes, ponds, and slowly flowing waters with low to moderate nutrient levels. Cyanobacteria of this type play roles in primary production and, in certain metabolically active strains, may contribute to nitrogen fixation in nitrogen-limited aquatic systems. The taxonomy of small-celled Chroococcus species remains challenging, with morphological overlap between species and significant variation in cell size related to environmental conditions and growth stage. Recent molecular studies have revealed that morphologically defined genera such as Chroococcus represent multiple phylogenetic lineages, indicating likely future taxonomic rearrangements. The species is not assessed by the IUCN.

Shared Countries

Both species can be found in 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden