Stanly Coren, professor of psychology in British Columbia, explains, "current studies show that dogs have a brain equivalent to a two or three years child". Besides, the best friend of human is able to feel pain, sadness and even depression, although probably "It lacks of the necessary emotional intelligence to understand the permanence of death".

A greater number of canine cognition research show that they are emotionally complex animals with high degree of social intelligence. Indeed, they are able to understand human language, woice tone, nonverbal language and even their sights (looks, eyes maybe?) to decipher what they are saying.

However, Coren believes that "they don´t know that their owner is gone forever". About why they are waiting next to their graves, Coren believes that "probably they are waiting to come back. I don´t think the dog surprised if the owner suddenly opens the coffin and sits next to him"