Answer:
“There was something calling to him out there in the open. His mother heard it, too. But she heard also that other and louder call, the call of the fire and of man.”
Explanation: There is an instinct they are feeling and a fear. This is an internal conflict-- making a decision between opposing feelings or ideas. We can only imagine how animals feel or "think", but we assume it may be similar, in some ways, to human instinct, feelings and thought.