Because by the dictation of the senses we are committing sinful activities life after life; therefore we are in different grades of bodily presentation. Don't think that everyone is of the same standard. No. According to one's own work he gets a type of body. So these different types of body are due to different grades of sense gratification. So sense gratification is there in the hog's life also. Why he has been offered a body of the hog?
So much sensuous that it has no discrimination who is mother, who is sister, or who is this or who is that. This is practical, you'll see. The dogs and hogs, they are like that. In human society also there are many who don't care who is mother, who is sister or who is this. The senses are so strong. And this is our cause of all miseries. Try to understand.
The threefold miseries that we are suffering, that we are trying to make a solution, is due to this dictation of the senses. Therefore Kṛṣṇa is there. Kṛṣṇa is there. His name is Madana-mohana. If you try to transfer your love from sense to Kṛṣṇa, then you see the result. Immediately you'll find. Sevonmukhe hi jihvādau (Bhakti-rasāmṛta-sindhu 1.2.234).