How Black Bears Trekked to Ontario

Can you show me the way to Ontario...?

The Pleistocene is the geological epoch immediately before our own. It ended just ten thousand years ago, a time so recent on a geological timescale that the modern epoch isn't even visible on the chart of the Age of Mammals shown below - its effectively just the line at the very top of the column. It's hardly surprising therefore that, for the most part, the animals alive in the Pleistocene are the same ones that are alive now, barring those that have gone extinct over the course of human history.

The Pleistocene, however, represents the Ice Ages, when vast glaciers covered much of the landmass of the northern hemisphere (rather less so in the south, though, because Australia and Africa, in particular, don't get as close to the south pole as Europe, Asia, and North America do to the northern one). It ends with two events that occurred roughly at the same time: the warming of the world at the end of the last Ice Age, and the dawn of human agriculture. In the case of North America, humans only arrived at the very end of the Pleistocene, meaning that it represents the last time that the continent was untouched by human hands.