For the earliest human societies, what was the best source of protein? *

Large hooved animals.

Explanation:

The best source of protein for earliest humans are the large hooved animals because they have a large amount of meat present in their body which is a big source of protein. Early humans need protein in large amount because protein has high amount of energy and these humans also need protein in large amount due to their hard working behavior which makes necessary the intake of protein in large amount in every meal.