Ed said:
Also you would have to take into account the region and what is available, the culture of the people (which we can only guess at with prehistory).... there are many factors involved in this....
A prime example of this are the mongolian horsemen of today who gain all their food and most things they need to live from the horses... very little vegitation is used at all... they believe it is bad to be tied to the land and that is a main factor in the continuation of their nomadic existance.
Ed
The Mongolians you mention don't eat their horses, so far as I know, but please correct me if I'm wrong.
They may drink koumiss (fermented mare's milk), but that is as far as it goes.
They hunt prairie dog like animals, using small calibre rifles (.22 or .38, I think) mounted on a bipod. An essential bit of kit for this is a special hat with long ears.
Don't laugh, it's true!
You lay on the plain, with your rifle on the bipod, and your hat on your head. After a while, you pull a string so the ears on your hat stand up. The prairie dogs are naturallu very curious animals, and will start to stare at your hat, wondering what sort of animal you are. When there are enough of them in view, and you think you might get a few, you shoot.
They also herd yaks, which provide flesh, milk (which can be turned into yoghurt and butter) and leather. Maybe the herd goats and sheep, too, which will provide more milk, flesh, leather and wool which can be turned into felt or woven into cloth.
Now, getting back to the original question, not all of Erope, or even our island, was covered with dense forest. There would have been expanses of marshland (modern East Anglia, for example) and grassy flood plains (what is now the Vale of York, for example), too. Early settlers probably lived in transitional areas, where they could hunt and trap on the plains and the fringes of marshland, catch fish, and take wood from the forest for fuel and lumber.
Keith.