In an “Ancient Greek” technological world a magical plague causes the extinction of all animals larger than a chicken, or say 5lbs/2kg. Some Humans and small animals (cats and dogs) survive this by virtue of being deep underground.
1000 years passes.
- Would many species of flora end up dying off?
- Would the dominant species end up being hares, boars and hawks?
- How would the lack of draft animals effect society?
- How would the lack of animals effect warfare?
- How much larger can existing animals be bred over hundreds of years?
- What sort of unknowns have I not considered?