The cats and dogs can kill their eatable animals, and for that there is no question of sin on their part. But if a man kills an animal for the satisfaction of his uncontrolled taste, he must be responsible for breaking the laws of nature. And in the Bhagavad-gītā it is clearly explained that there are three kinds of activities according to the different modes of nature: the activities of goodness, the activities of passion, the activities of ignorance. Similarly, there are three kinds of eatables also: eatables in goodness, eatables on passion, eatables on ignorance. They're all clearly described, and if we properly utilize the instructions of the Bhagavad-gītā, then our whole life will become purified and ultimately we shall (be) able to reach the destination. Yad gatvā na nivartante tad dhāma paramaṁ mama (BG 15.6).