Wildlife ecologists have seen white-tailed deer expanding their range in North America over many decades. And since the early-2000s these deer have moved north into the boreal forests of western Canada. These forests are full of spruce and pine trees, sandy soil and freezing winters with lots of...

No matter what you're doing right now – sitting, standing, walking – you're moving. First, because Earth is spinning around on its axis. This rotation is the reason we have days. Second, because Earth and other planets in our solar system are orbiting the sun. That's why we have years. Third,...