The beaver, often called nature’s engineer, is a semiaquatic rodent whose environmental modifications profoundly affect the landscapes they inhabit. Understanding the global population is complex, as the total count is an estimate derived from combining figures for the two distinct species found across the Northern Hemisphere. Precise, real-time censuses are impossible due to their nocturnal habits and the vast, often remote territories they occupy. The global count is a composite figure reflecting the different population statuses of the two species.
Differentiating the Two Global Species
The total number of beavers is determined by the populations of the two recognized species: the North American Beaver (Castor canadensis) and the Eurasian Beaver (Castor fiber). These species are geographically distinct, with the former inhabiting North America and the latter found across Europe and Asia. Genetic and morphological evidence confirmed their separate status, though they were once considered a single type of animal.
The most definitive biological distinction lies in their chromosomes; the Eurasian beaver has 48 chromosomes, while the North American species has 40. Physically, the Eurasian beaver tends to be slightly larger with a longer, narrower skull and a narrower, more pointed tail. In contrast, the North American beaver typically has a more rounded head, a shorter, wider muzzle, and a wider, more oval-shaped tail.
Current Population Estimates and Distribution
The vast majority of the global beaver population belongs to the North American species. Current estimates suggest that Castor canadensis populations hover around 10 to 15 million individuals across North America, including the United States, Canada, and parts of northern Mexico. Their distribution is widespread across most of the continent, reflecting a successful recovery from historic lows.
The Eurasian Beaver (Castor fiber), which once faced near-extinction, has a significantly smaller but rapidly expanding population. Recent estimates place the total number of Eurasian beavers at over 1.5 million individuals, concentrated primarily in Europe and Western Russia. Roughly half of this population is found within Russia, with the remainder distributed in fragmented and recovering populations throughout Scandinavia, the Baltic states, and Central Europe. Estimates are formulated using methods like territory mapping, aerial surveys, and modeling based on habitat suitability and known family group sizes.
Historical Population Declines and Recovery Efforts
Both beaver species experienced catastrophic population declines between the 17th and 19th centuries due to the intense demand for their pelts and the glandular secretion, castoreum. Before this era, the North American beaver population may have numbered in the hundreds of millions, while the Eurasian beaver was widespread across the Palaearctic region. The relentless fur trade decimated these populations, pushing both species to the brink of extinction.
By the early 20th century, the North American beaver population had plummeted to an estimated 100,000 individuals. The Eurasian beaver was reduced to as few as 1,200 animals across only eight isolated populations. The subsequent recovery was driven by the collapse of the fur trade and concerted conservation efforts, including governmental protections, habitat restoration, and systematic reintroduction programs across both continents.
In Europe, the recovery of Castor fiber began with the protection of remaining small groups and a wave of translocations starting in the 1920s, which helped re-establish the species. In North America, reintroduction and translocation efforts from the mid-20th century onwards were instrumental in restoring Castor canadensis to many parts of its former range. These sustained conservation actions have resulted in the current estimated global population of over 11 to 16.5 million beavers.