When Giant Prehistoric Beavers Roamed The Don Valley Brick Works

Giant beaver vs. modern beaver

Hooooooo boy. Meet the giant beaver. This is one of the largest rodents to have ever walked the earth. And thank god for that. It was eight feet long and weighed 200 pounds. So, like, the size of a black bear. A freaking bear. It's teeth were six inches long, but scientists aren't actually sure if they used them to chop down trees like beavers do today; giant beavers probably ate aquatic plants, and we've yet to find any evidence that they built giant dams either. Their tails were probably pretty different from their modern cousins, too: longer and thinner. And they had shaggier hair.

They also used to live in Toronto. Or, um, on this land anyway. They were here about 130,000 years before our city was founded.

In the late 1800s, Toronto's most famous and celebrated geologist ever, Arthur Philemon Coleman, who had an awesome old-timey moustache, discovered the importance of what would soon become a crazy-world-famous (well, by geology standards anyway) formation: the big cliff on the northern end of the Don Valley Brick Works. At the bottom of the cliff was a bedrock of slate from about 450 million years ago — littered with fossils from the days when this part of the world was a tropical sea filled with trilobites. But what really makes the cliff special is what Coleman discovered above that slate: a remarkably complete geological record of the last 135,000 years.

Layer by layer, the exposed earth clearly shows the last two Ice Ages coming and going, leaving rocks and dirt and boulders behind as enormous glaciers covered this land in ice and then melted away as the climate changed. It's the only place in this part of the world where you can see all of that history laid out in front you. I's super-crazy-important.

Now, in between those two Ice Age layers there are a bunch of other layers from the time when the planet was warmer. One of them, near the bottom, is a layer of sand and clay from about 130,000 years ago. And that's where A.P. Coleman found the giant tooth of a giant beaver.

In our giant beaver days, Toronto was actually a couple of degrees warmer than it is now. Instead of Lake Ontario, there was an even bigger and deeper lake; they call it Lake Coleman in honour of the moustachioed geologist. So everything that's now downtown T.O. was very much underwater back then. And the clays and sands that are at the foot of the cliff in the Don Valley Brick Works – all the way north of Bloor – would have been in the shallow waters near shore, at the mouth of the prehistoric ancestor to the Don River.

A.P. Coleman

Colemen and his peeps were able to piece the scene together from the other fossils they found along with the beaver tooth. The area where the river met the lake was a marshy wetland back then, surrounded by woods and grasslands. Prehistoric stag-moose, bigger even than moose are today, with huuuge sets of antlers, roamed through a wilderness that would have seemed to us both familiar and strange. There were plenty of plants and trees that still grow all over the place in modern day Toronto: oaks and pines and maples, willows, cedars and elms. But there were also some species that you can only find further to the south these days, in the States where it's warmer, and even a few that are long-extinct. There were giant prehistoric bears here, too. Massive, ancient bison. Woodchucks and white-tailed deer. On occasion, a thunderstorm sparked a forest fire, flames tearing through forests and fields, enormous panicked beasts rushing for the safety of the water.

Scientists figure that giant beavers didn't spend much of their time on land; even less, it seems, than beavers do today. They stuck to the swamp at the mouth of the river, swimming through the marsh, feeding on the aquatic reeds and long grasses that lined the shore, maybe even cutting down trees and building beaver lodges big enough to house a family of rodents the size of a bear. They'd been living like this, in the wetlands of North America, for two million years. And they had more than another hundred thousand years to go.

But not in Toronto. As the next Ice Age began, Toronto got colder, eventually getting buried beneath a layer of ice two kilometers thick. The giant beavers would have been forced far to the south. And as the Ice Age ended, around 10,000 B.C. or so, the last members of the species died out. The giant beaver was extinct.

By then, a new species had arrived in North America: us. Back in the days when giant beavers had been swimming around the Don Valley, we'd been living on the other side of the world, having just recently evolved on the savannahs of Africa. But soon, the Ice Age shrank the great deserts and seas that blocked the way out of that continent, and Homo sapiens were unleashed. It took us tens of thousands of years to spread all the way over to this part of the world. But when we did, we dominated it: first the indigenous peoples who developed cultures and civilizations throughout the Americas; and then the colonizing, clear-cutting, genocidal Europeans.

On this spot, the British founded a new capital. To build it, they needed bricks. To make bricks, they needed clay. And one of the best sources for clay was discovered in the very same spot where that prehistoric river once met that prehistoric lake. The Don Valley Brick Works was born, turning clay into red and yellow bricks of such a high quality that they won gold medals at the Chicago World's Fair. A lot of Toronto's old buildings are made of Brick Works bricks. Much of our city was quite literally built from the mud of the swamp where giant beavers once roamed.

Today, the Brick Works is no longer an industrial wasteland. Instead, we've returned it to its roots: a mixture of wetlands, forests and fields. Native species of plants and animals have been reintroduced and allowed to thrive – some of them are the very same species that would have been here in the days of the giant beaver. In fact, if you get really lucky, you might even spot one of the newest residents: a modern, normal-sized beaver, swimming around the wetland where 130,000 years ago his giant beaver cousins did the very same thing.

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The ROM has a giant beaver, along with other prehistoric beasts who would have lived in these parts on display, which is raaaaather cool. And a few indigenous nations, like the Mi'kmaq and the Cree, have myths about giant beavers.

You can read more about the north cliff of the Brick Works here, at the oh-my-god-so-good Lost Rivers site.

There's a neat photo of the cliff from it's industrial days here and the wasteland that was the quarry here. 

Oh and Torontoist is currently running a series on our city back in its prehistoric days. They've started with a couple of posts about super-super-super old stuff. You can find them all here.

Here, also, since I made this list and didn't use it but don't want to delete it, a few of the plants A.P. Coleman and his team discovered evidence of from that period 130,000 years ago: sugar maples, ash, cedar, hickory, willows, elm, locust trees, oaks, white pine, sycamore, sedges, which are like rushes, mare's tail, algae, mosses.

And then there's this video about giant beavers from a Discovery Channel series called "Prehistoric New York":