an interesting article
http://theprancingpapio.blogspot.com/2010/07/do-animals-keep-pets.html
Herzog points out that while some animals are documented having pets, this behavior almost always happen in captive or semi-captive environment where food and shelter are provided. The author believes that humans are “true” pet owners because the owner-pet relationship occurs in a natural setting and argues that animal pet owners are not “true” pet owners because they do so in captive or semi-captive settings. Thus, Herzog believes that humans are the only animals that keep pets.
Looks like another case of “humans are exempt from the logic we apply to the rest of the living world”. What makes Herzog think humans are free ? If anything id say his observations point to the idea that humans are either domesticated and/or captive. At least our interactions seems similar to observed behaviour of other captive/domesticated animals.