If you're expecting another Ice Age sequel, look elsewhere: This ain't one of those shows you can plonk the kids down in front of and run. Alice Roberts is taking us back in time (over 40,000 years to be precise) this evening as she examines the latest discoveries from the northern hemisphere, which just so happen to tell us a little bit more about the kinds of creatures who were living on this here planet in the old days. First on the agenda is a trip to North America, where sabre-toothed cats and bear-sized Shasta ground sloths once roamed the earth...