Owning a pet is very popular in the U.S. The most recent survey from the American Pet Products Association estimated that 65% of American households (79.9 million) include at least one pet. The most popular household pets are, unsurprisingly, dogs (44% of households) and cats (34.9% of households) .
Psychologists have long been fascinated to uncover whether individual differences drive pet ownership and preference. Most have focused on comparing the so called cat and dog people. Perhaps driven by the natures of their respective favorite pet, cat people are stereotyped as quiet, sensitive, and unorthodox while dog people are thought of as gregarious and energetic. One of the most comprehensive studies to-date  analysed 4,565 participants who took the Big Five personality Inventory and self-identified as dog people, cat people, both or neither. They found that dog people are higher in extraversion, agreeableness and conscientiousness and lower in neuroticism and openness, even when controlling for gender differences. Contrary to these findings, some failed to uncover differences between the two types  or suggested the labels do little more than offer a different way of saying masculine and feminine .
To shed new light on this debate, we analysed two different online behaviors using big data from social media:
- Mentioning animal names in Facebook posts;
- Using a profile picture featuring cat or a dog on Twitter.