Is there a difference in kamma between harming a human and an animal?
The intensity of the kamma depends on the level of existence of the being affected. Humans are on a higher plane of existence than animals, hence harming a human produces more intense kamma. Similarly, harming a virtuous person produces even greater intensity of unwholesome kamma. The effects of wholesome kamma are also intensified if the recipient of our action is a person of high virtue. That is why Buddhists like particularly to perform acts of generosity towards virtuous monks.
