No cows in zoos. So the biologists didn't study them. Because of cow patties, there are always lots of flies in cow pastures. Anyone who has been in a cow pas

No cows in zoos. So the biologists didn't study them. Because of cow patties, there are always lots of flies in cow pastures. Anyone who has been in a cow pasture in summer would easily notice that cows use their tails the same way as horses do: to chase away flies.