On the left the paw of a Gray wolf (Canis lupus), on the right the hand of Jim Dutcher, a large, grown up man. To give you an impression how big Gray wolves are. Another comparison here Picture by Jim and Jamie Dutcher
Labrador Retriever - Labs are the smartest guide dogs. They are highly trainable and are very eager to please. This is also why Labs make such great family pets and are the most popular dog, according to AKC Registration Statistics.