Canadian beaver vs

Castor canadensis compared with Cocconeis placentula

Taxonomic Classification

Rank	Canadian beaver
Kingdom	Animalia (Animals)	Chromista (Chromista)
Phylum	Chordata (Chordates)	Ochrophyta (Ochrophyta)
Class	Mammalia (Mammals)	Bacillariophyceae (Bacillariophyceae)
Order	Rodentia (Rodents)	Achnanthales (Achnanthales)
Family	Castoridae (Beavers)	Cocconeidaceae
Genus	Castor (Beavers)	Cocconeis
Species	Castor canadensis	Cocconeis placentula

Conservation Status

Canadian beaver

NE — Not Evaluated

Population: ~15.0M

Trend: Stable →

NE — Not Evaluated

Physical Characteristics

Attribute	Canadian beaver
Diet	Herbivore	—
Average Lifespan	15 years	—
Average Length	1.0 m	—
Average Weight	25.0 kg	—

Habitat & Geographic Range

Canadian beaver

Habitat

Typically found in grasslands, forests, and vegetated habitats.

Range

Widely distributed across Europe (15 countries), North America (United States), and South America (Argentina, Chile).

Habitat

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

Range

Distributed across Brazil, Norway, Portugal, Sweden, and Taiwan.

Canadian beaver

The largest rodent in North America, Canadian beavers weigh up to 32 kg and are master ecosystem engineers inhabiting rivers, lakes, and wetlands across Canada and the northern United States. By felling trees and constructing dams up to hundreds of meters long, beavers create ponds that provide habitat for hundreds of species. Their lodges and canals transform entire watersheds. Once nearly hunted to extinction for their fur, beaver populations have recovered strongly.

Cocconeis placentula is among the most ubiquitous and widely studied freshwater and brackish-water diatoms worldwide, serving as a model organism for periphyton ecology and a key species in biological assessment of water quality. A member of the family Cocconeidaceae, this adnate epiphyte produces a characteristic ovoid frustule with fine transapical striae, a well-developed raphe system on one valve, and an elaborate pattern of areolae visible under electron microscopy. The species complex encompasses several morphological varieties (var. placentula, var. lineata, var. euglypta, var. acuta) that differ in fine structural details of the valve ornamentation. Cocconeis placentula colonizes the surfaces of aquatic plants, algae, rocks, and sediment particles in rivers, lakes, and ponds across a vast global range spanning Europe, the Americas, Asia, Africa, and beyond, tolerating a wide range of water temperatures, pH values, and moderate nutrient enrichment. Its abundance varies dramatically with substrate type, light availability, and water chemistry, making community composition data involving this species valuable in diatom-based paleolimnological reconstructions and modern bioassessment indices. As a benthic primary producer, C. placentula contributes substantially to the productivity of the photic benthos and serves as a dietary component for invertebrate grazers. Its remarkable cosmopolitan distribution and ecological flexibility make it one of the defining species of freshwater periphyton communities globally. Conservation status is not formally assessed.