Zhou Tian could think of things, and the other creatures in this world could as well. After all, it wasn't possible that Zhou Tian was the only smart one around. For certain things, even if those creatures themselves wouldn't think of it, having experienced much, they too could discover the best method of operation from the results of their actions.
And knowing about hunting large-sized creatures, wouldn't some beings in the world, as long as they had the ability, also know to hunt those large-sized creatures?
After all, most creatures in this world were quite small, and for some beings, to hunt these small creatures, they wouldn't know how many times they needed to eat each day. If they were really to do so, they would probably have no need to do anything else all day long, they would just need to continually hunt for food to deplete their daily time.