Man has been with the earth for several millions of years. Perhaps five, perhaps two, or perhaps less, depending on how the difference between man and a man-like ape is defined. At all events it is quite a long time in human terms; long enough for the ice-sheets to have ground their way several times across our northern latitudes and disappeared again towards the pole.
In very general terms man has, in fact, been around during the same period as that in which the earth has been undergoing its succession of glaciations and de-glaciations. No one knows for sure how many glaciations and de-glaciations there have been. Until recently it was thought four or five, but in many places on land there is no real proof of more than two, although evidence from the sea is now suggesting a dozen or so cold periods.
Whether there were two or five or fifteen cold periods, men rode them out patiently for a couple of million years as best he could, leaving little trace of anything that can be called higher social organisation or civilisation of any sort. As the climatic belts migrated slowly too and fro and countless generations succeeded each other he moved around in small groups into the most favourable locations, well to the south during the periods of extreme cold. He must have been quite few in numbers and he must have lived in balance with the natural environment of which he was not the master, but a competing part.
This man was us; the roots of each of us reach back to every single individual whose line reproduced itself. It took us one hundred thousand generations to get through the Ice Age and we scarcely changed our habits – we never wrote, never discovered the wheel, never took up farming; even though at birth we were all the time not so very different from the individuals we now are in the Golden Age.
We certainly used crude tools, which we improved as time passed, and we learnt the use of fire. We must have kept burning down great swathes of forest. We could communicate with one another better than other higher land animals, and languages grew, changed and were absorbed as we clawed our way through the dangerous world of pre-history.