So we travel back to the Dark Ages, the early medieval years when constant migration of barbarians kept civilization to a lower level than Rome had reached. Most of Europe is heavily forested. Settlement tends to be along rivers and the sea coast, and travel, too, is restricted to coastal and river sailing.
Let’s take note, first, of what wild animals are already living in Europe. Wolves are everywhere, but they are food only for the truly starving. Medieval people thought that wolves were poisonous, both their bite and their meat. Wolf fur could be used, but it had a bad smell.
Bears, deer, boars and mountain goats were the large game animals. Fallow deer were native to the Mediterranean; larger red and roe deer were further north and in the British isles. During the Dark Ages, bears were hunted to extinction; boars were hunted as enthusiastically but somehow survived much longer, remaining popular hunting targets all through the Middle Ages. Foxes, otters, hares and beavers were the main mid-sized game.
In the 7th century, Northern Europe had no rabbits or cats (apart from thinning numbers of lynx in the mountains). Rabbits were native to North Africa and Spain, though they were carried north by Romans—and eventually they became an established wild animal. In the 7th century, some places would have had rabbit warrens, others not yet. Rabbits can be domesticated, where hares cannot.
There were more donkeys than horses, and horses were not very big. Oxen were smaller than today’s cattle, nor were they distinct breeds. In fact, sheep were more often milked than cows; cattle were the main animals for pulling carts and plows.
Pigs were kept half wild; they foraged in the woods during summer and had to be rounded up for winter. Pigs were omnivores on the farm, so with sheep, they were Europe’s most numerous farm animals. Farm fowl included chickens, but geese and ducks were more common and also closer to wild.
One great thing about the Dark Ages: the water was teeming with fish. Every pond was full of eels, every river was still unpolluted and filled with fish, and you didn’t have to go very far out into an ocean bay to start hauling in the big stuff. Early European diet, based on the river and sea shores, can be presumed to consist very largely of fish, with an infusion of stewed hare, boiled eggs and roast boar.
Edible plants were the long-term problem that the Dark Ages farmers set out to solve…