I love animals but I have never had the opportunity to work with them
I like some animals, specially is dogs, it's so clever, my daughter have a dog that's a keep house one, as when people come or go through her house then it barks them, and it plays with my grand-children as a human being. Look funny, as it knows they are its host, it never make harm for them.
LOL ... I was gonna answer, but got distracted thinking about why mules are described as "pig headed" ... But we say a person is "stubborn as a mule".