Cool Beaver Fact #1

The beaver was once classified as a fish

While the beaver is certainly an agile swimmer and is at home in the water, it is most definitely not a fish. In fact, there are some reptilian ancestors… and then some amphibian ancestors in between beavers and fish.

 

This is a tree of vertebrates and shows which classes have common ancestors. Beavers are mammals and would fall under the category of “Rodents and rabbits” in this tree. To get truly specific, the North American beaver is of the order Rodentia, the family Castoridae and the genus Castor and the species is called canadensis. This means that the North American beaver is a castorid rodent (of which only two species survive today), that we call Castor canadensis. Their closest relatives are squirrels and marmots.

Regardless of the beaver's true position in the tree of life, in 1760 the College of Physicians and the Faculty of Divinity in Paris declared the beaver to be a fish! The logic behind this classification goes something like this:  fish have scales, beavers have scaly tails, therefore the beaver must be a fish. Though, beaver tails are actually just leathery, not scaly like a fishes scales. The motive for this classification was really so that beavers could be eaten during lent. Meat (but not fish meat) is prohibited during Fridays in Lent, but if beavers were fish it would not be a sin to eat them. Similarly, in the 16^th century, the pope declared the largest rodent in the world, the capybara, to also be a fish. During this period, every year 400 tons of capybara was eaten during Lent.

Lastly, here is a new (possibly?) beaver inspired movie: