Two Brothers

Set in 1920s French Indochina, two tigers are separated as cubs after the ancient temple where they live is disturbed by Aidan McRory (Guy Pearce) who intends to steal and sell the ancient statues.Two tiger cubs are playing when one (later named Sangha) comes upon a young civet. Sangha chases the civet into its burrow and the mother civet appears and chases Sangha up a tree. The other tiger cub (later named Kumal) appears and chases the mother civet away. Gunshots are heard, and the tigress arrives to protect the cubs. She picks Sangha up and runs for safety. Kumal follows, but can't keep up and falls behind. The cubs' father appears, but the men have caught up with them and he is shot dead by McRory.McRory is an unscrupulous explorer, big-game hunter and temple looter. He discovers Kumal and befriends him, but McRory is arrested for stealing from the ancient temple and Kumal is kept by the chief in the Cambodian village where McRory had been staying. The chief then sells Kumal to a circus where he is to be the star attraction.
Sangha remains in the jungle with his mother, but both are soon trapped by McRory as game for a vain Khmer prince to hunt. The mother is shot in the ear and thought to be dead before she jumps up and runs off with a hole in her ear. Sangha is discovered by young Raoul, son of the French administrator, Normandin, and becomes the child's pet. However, Raoul's mother's dog, Bittsi, a schipperke, is a constant antagonist to the young tiger.
Kumal is trained by cruel circus ringmaster Zerbino to do tricks, such as jumping through a flaming hoop. Sangha meanwhile dwells peacefully with Raoul until he is at last cornered by Bittsi following a prolonged chase. In self-defence, Sangha attacks Bittsi, badly wounding although not killing him. This provokes a hysterical reaction from the household, particularly Raoul's mother, who insists that Sangha has "got the taste of blood now" and gets rid of him. As a result, he is made a part of the prince's palace menagerie, where he quickly gains a reputation as a ferocious beast. Sangha and Kumal are now very close to each other.The prince then decides to hold a festival in which a battle between two great beasts - the brother tigers - will be the centerpiece. When placed in the cage before the audience during the festival, the two brothers do not immediately recognize each other, and Kumal is afraid to fight. However, when the brothers finally recognize each other they begin to play together instead of fighting, and the audience likes this but the trainers don't. The trainer attempts to antagonize the tigers into fighting, but as he opens the cage to shoot one, the tigers escape, managing to frighten the trainers and the audience into the cage themselves.The two tigers escape, and McRory is determined to hunt them down. After Kumal showing Sangha how to jump through fire to escape, McRory and Raoul find them. However, as McRory takes aim at Sangha, Kumal appears, and demonstrates that he remembers the sweets McRory used to give him. McRory puts down his gun and vows never to hunt again.The two brothers make their way back to their temple home in the jungle where they meet up with their mother (who can be identified by the hole in her ear). Just before the credits, some comments to save the tigers (as a species) are shown.

Question: Who attacks Bittsi in self defense?
Answer: Sangha