When 200-Pound Beavers Roamed Southern Ontario

Bear-sized beavers once paddled through southern Ontario wetlands. Fossils of these awesome beasts have been found in Highgate Ontario east of Chatham and in Toronto at the Don Valley Brickworks. These mega-beavers weighed 90 to 125 kilograms (198 to 276 pounds). 

As much as I’d like to imagine these giant beavers cutting down trees – really big trees! – it seems unlikely that they were the lumberjacks that their modern counterparts are. Studies of their teeth suggest they generally grazed on aquatic plants, like water lily tubers.  

There has also been no evidence found of giant beaver dams or lodges constructed by these animals. However, structures made of branches and other vegetation would not preserve well in the fossil record. 

Just for fun, let’s imagine a lodge big enough to shelter these enormous rodents. Our modern beavers construct impressive dome shaped lodges that can be taller than an adult human. A lodge spacious enough for giant beavers would have been a towering edifice!

The last refuge of giant beavers in North America was the Great Lakes region, and they eventually succumbed here about 11,000 years ago, perhaps due to climate change eliminating their wetland homes. 

Intriguingly, the mythologies of Innu, the Mississaugas, and the Anishinaabe tell stories of giant beavers. It’s fascinating to speculate that humans and giant beavers once co-existed in this part of the world. 

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Giant beaver fossils were first found in a cave in Ohio along with fossils of other extinct mammals including a species of peccary (wild pig), a species of moose called a “stag moose”, and a colossal bear called the giant short-faced bear which weighed up to a staggering 900 kilograms or 2,090 pounds!  

In the not-so-distant past, our area of the Great Lakes region was home to a menagerie of fantastic beasts, including one very stupendous beaver!