Why? Because they are the most intelligent, loyal and affectionate! And therefore, the most popular dogs that perform in the circus are poodle dogs. They are also excellent hunters and shepherds! A 1994 study by Stanley Corey ranked them second out of 110 breeds in intelligence. They are an active dog, requiring regular physical and intellectual activities. Though not suitable as a guard dog because it is neither a territorial breed nor particularly aggressive, Poodles tend to be protective of their families.