Reintroduction of the Eurasian Beaver opus 866
| 13 June 2026 1350 Hours | | Biology, Behavior, Conservation, Environment, Genetics, History, Mammalogy, Migration, Population, Science, Zoology |
The most lasting introduction of the North American beaver (Castor canadensis),
To Europe, occurred in an introduction in 1937.
During that period the Eurasian beaver (Castor fiber) was near extinction.
Conservationists then imported seven North American beavers from Canada.
Realized much later, the two species are distinctly different
And cannot interbreed: American has 40 chromosomes,
Eurasian has 48 chromosomes.
The North American species thrived in Finland and spread,
Outcompeting the native Eurasian beaver, creating a great conflict.
Additionally, several countries have reported small records.
Escapes were recorded in 2006 from the Eifel--Zoo in Prüm, Germany.
Small, unsuccessful releases occurred in Poland and Ukraine
During the 1920s and 1930s.
Now, authorities have begun eradication and sterilization programs.
The North American beaver has larger litters and builds larger dams.
It is now classified as an invasive alien species of Union concern.
In the meantime, Eurasian beavers are being reintroduced,
After being hunted for meat, fur, and castorium (used in meds and perfume).
From just 1,200 individuals, the Eurasian population is now 1.5 million.
There have been major recovery zones in Great Britain,
Scandinavia, Western and Central Europe, Italy, and Iberia.
Reintroductions have stabilized and expanded
Mongolian and northeastern Chinese populations.
The expansion of both natural Eurasian and North American populations
Within their original ranges is always favored.
Their dams reduce flooding by slowing stream flows;
They trap water on the landscape, reducing drought;
And they augment biodiversity for amphibians, fish, birds, and rare insects.
At last humans have seen the light, at least with this one, just in time!
It took some good genetics (unknown at the time) to become a reality.