The woolly mammoth is perhaps the first animal that comes to mind when we think about the extinct fauna of the Pleistocene, or Ice Age. It seems very odd to us today that there were elephants thriving right across Europe and Asia, and in North America too (the Colombian mammoth). What's really remarkable, though, is just how much we know about this extinct creature. Scientists have discovered and analysed the bones and tusks of woolly mammoths, unlocking secrets from the past about mammoth biology. From analysis of mammoth DNA, we even know that they had a special, cold-adapted type of haemoglobin, which could deliver oxygen to body tissues at very low temperatures. I was astounded to discover just how much information is locked away inside tusks; I met mammoth expert Dan Fisher in Ann Arbor, Michigan, and he sliced open a tusk to show me the yearly growth lines inside it. And under magnification, you can even see daily lines. It's phenomenal.