Lost Giants: Large Canadian Mammals That We Cannot Replace

Elephants 

While three species (Elephas maximus, Loxodonta africana, and Loxodonta cyclotis) of elephant survive, there used to be many more across the globe, including three in Canada. These were the American mastodon (Mammut americanum), the Columbian mammoth (Mammuthus columbi), and, most famously, the woolly mammoth (Mammuthus primigenius). Elephants were, as they still are, very important keystone species that had a significant effect on vegetation. While the Americans have entertained the idea of using African and Asian elephants as proxies for these creatures, they have only done so in areas where, importantly, it does not snow. Living elephants do not have much fur, being tropical and desert-adapted creatures. This makes them decent as possible proxies for the Columbian mammoth, at least in warm places. However, even the plains of Canada are probably too cold for free roaming elephants. It might be conceivable that they be used in the warmer parts of the year and housed at others, but that is a less than favourable situation. It seems unfortunately that the only ways to get the same sort of ecological impact created by Canadian elephants are to either bring them back by cloning, modify existing elephants to be able to survive here, or to try and reproduce those effects using heavy machinery. None of these are particularly easy. I briefly entertained the idea of giving the elephants sweaters, not that it would work but how adorable would that be. 

Sloths 

There was one giant ground sloth species present across Canada, from the plains to the arctic. This was Jefferson's ground sloth (Megalonyx jefersoni), which stood about three metres tall and weighed a thousand kilograms. Like elephants, ground sloths were major environmental engineers, tearing down trees and browsing leaves. The closest living relatives of the ground sloths are the tree sloths, which are very small and in no way the ecological equivalent of their giant cousins. The Americans have discussed all sorts of animals as proxies for their ground sloth species, including rhinoceroses, anteaters, and giraffes, none of which are practical or even viable here, due to climatic restraints. It is hoped that the takins being considered as woodox proxies will also fill some of the role of the ground sloth, due to their ability to rear up on their hind legs in order to reach leaves. It is not a perfect solution, but such things are rare. 

Beavers 

Canada was also home to a creature known as the giant beaver (Castoroides ohioensis), a large rodent about the size of a black bear. Not much is known about it's behaviour, such as whether or not it built damns, and so finding an ecological proxy for it is made doubly difficult.