The bear needs the cat. The cat needs the lion. The dog needs the bear. The lion needs the cat. If something is young and it eats the bear then the bear eats the lion. If something is cold then it eats the lion. If something eats the dog then it needs the cat. If something visits the lion and it is blue then it is young. If something needs the lion then the lion is cold. If something eats the cat then it is young.
The dog does not need the bear.