vs Common Water Rat

Chroococcus macrococcus 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 macrococcus	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 Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway, Sweden, and United States.

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Chroococcus macrococcus is a cyanobacterium in the family Chroococcaceae, belonging to a group of unicellular to loosely colonial coccoid cyanobacteria distributed in freshwater and moist terrestrial environments. The specific epithet macrococcus refers to the large size of the cells, distinguishing this species from smaller-celled members of the genus. Chroococcus cells are characterized by their spherical shape, division by binary fission into pairs or tetrad arrangements, and enclosure within distinct gelatinous sheaths. The outer sheath layers are often visibly stratified in older colonies. Cyanobacteria of the Chroococcaceae occupy a broad range of aquatic and semi-aquatic habitats worldwide, from standing and flowing freshwaters to damp soil, rocks, tree bark, and the surfaces of other organisms. They are among the most ecologically resilient of photosynthetic microorganisms, tolerating desiccation, temperature extremes, and nutrient-poor conditions. Chroococcus macrococcus has been recorded from European freshwater localities. Its ecological significance lies primarily in contributing to primary production in aquatic communities. Like most microorganisms, it has not been formally assessed under IUCN criteria.

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.