A group of killer whales (虎鲸) were chasing (追逐) after a gray whale mom and her baby. Oh no! The killer whales caught the baby and killed it. Then, something amazing happened. A few humpback whales (座头鲸) came to save the mom. They beat the killer whales with their fins (鱼鳍) and tails. They swam around the baby and stopped the killer whales from eating its body.