Answer:
That he is a fighter who does not quit
Step-by-step explanation:
The passage implies that White Fang was previously attacked by a lynx before his encounter with Lip-Lip, which was quite a graphically described. This leads me to believe that even though the torn shoulder that White Fang endured hurt, he is fearless, and possibly quite stubborn for not retreating from any further conflict before his shoulder was healed lol