In 'Blue's Clues', what kind of animal is Blue?

In 'Hey Arnold!', what shape is Arnold's head often compared to? In 'Rugrats', who is the bossy three-year-old cousin? In 'Arthur', what kind of animal is Arthur Read? In 'Doug', what is the name of Doug's dog? In 'Barney & Friends', what kind of creature is Barney? In 'Thomas & Friends', what kind of vehicle is Thomas? In 'Paw Patrol', what is the name of the boy who leads the pups? In 'Bluey', what breed of dog is Bluey?