According to research at the California Institute of Technology, parts of the human brain are hard-wired to respond to other creatures.

(The study indicates that the brain’s right hemisphere evolved to deal with unexpected and biologically relevant stimuli and that covers a positive reaction to animals like fluffy kittens, as well as a negative response to creepy crawlies. Brain activity was stronger when the people studied looked at cats or snakes versus buildings or people. Maybe that is why more people view my animal vocabulary page, than my building vocabulary page.)