vs Common Water Rat

Chroococcus minimus compared with Hydromys chrysogaster

Key Differences

• is Not Evaluated while Common Water Rat is Least Concern.

Taxonomic Classification

Rank		Common Water Rat
Kingdom	Bacteria (Bacteria)	Animalia (Animals)
Phylum	Cyanobacteria (Cyanobacteria)	Chordata (Chordates)
Class	Cyanobacteriia	Mammalia (Mammals)
Order	Cyanobacteriales	Rodentia (Rodents)
Family	Microcystaceae	Muridae (Mice & Rats)
Genus	Chroococcus	Hydromys
Species	Chroococcus minimus	Hydromys chrysogaster

Conservation Status

NE — Not Evaluated

Common Water Rat

LC — Least Concern

Physical Characteristics

Attribute		Common Water Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Habitat

Native to Asia and Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Sweden, and Taiwan.

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Chroococcus minimus is a species of cyanobacteria in the family Chroococcaceae, representing one of the smaller-celled members of the genus, as the specific epithet indicates. Chroococcus is a cosmopolitan cyanobacterial genus found across a wide range of aquatic and moist terrestrial habitats globally. The cells of Chroococcus minimus are spherical, very small in diameter, and occur in pairs or tetrads enclosed within a thin, often inconspicuous mucilaginous sheath. Despite their miniature scale, these organisms are photosynthetically active and contribute to primary production in their aquatic environments. Small-celled cyanobacteria like Chroococcus minimus may dominate the picoplankton fraction of oligotrophic freshwater bodies, where their small cell volume provides a favorable surface area to volume ratio for nutrient uptake in nutrient-limited conditions. Chroococcus minimus has been documented from freshwater habitats in Europe and elsewhere. Identification of small-celled Chroococcus species is challenging due to overlapping morphological characteristics and the influence of environmental conditions on cell dimensions. Molecular phylogenetic studies have substantially revised the taxonomy of coccoid cyanobacteria. The species has not been assessed by the IUCN.

Common Water Rat

<em>Hydromys chrysogaster</em>, commonly known as the common water rat or rakali, is a semi-aquatic rodent in the family Muridae, native to Australia and New Guinea. It is classified as Least Concern by the IUCN, reflecting its relatively stable population across a broad range of freshwater and estuarine habitats on the Australian continent and associated islands. The species typically inhabits the banks of rivers, lakes, wetlands, and estuaries, where it constructs burrows in streambanks. It is highly adapted for an aquatic lifestyle, with partially webbed hind feet, a flattened head, and a dense waterproof coat. <em>Hydromys chrysogaster</em> is a carnivore, typically feeding on fish, crustaceans, mussels, frogs, and aquatic invertebrates, which it often carries to elevated feeding platforms to consume. The species is nocturnal and crepuscular, most active during early morning and evening hours near the water's edge. Biological traits including average lifespan, body length, and weight remain poorly documented in standardized databases, though adults are generally robust for a rodent, reportedly reaching body lengths of 20–35 cm excluding the tail. Geographic range details for this particular record remain incompletely documented in available data sources. Ecologically, the common water rat is an important apex predator in small-scale freshwater food webs and serves as an indicator species for wetland health in Australian riparian systems.