"Listen, you!" Mowgli cried. "There is no need for this dog's jabber. Ye have told me so often tonight that I am a man (though indeed I would have been a wolf with you to my life's end) that I feel your words are true. So I do not call ye my brothers any more, but sag [dogs], as a man should." —“Mowgli’s Brothers,” The Jungle Book,
Rudyard Kipling

How does Mowgli feel in this part of the story?

What is the cause of his feelings?