Dogs have been bred to make their appearance more appealing and their behaviour, at least to humans, more benign. However, beneath their lovable exteriors are the wolves from which they descend. Using underwater cameras to photograph a variety of breeds of domestic pets as they plunge into pools to retrieve objects, Seth Casteel has captured a little-seen side of dogs, illuminating a chaotic canine ballet of bared teeth, bubbles, enthusiasm and the acute focus of their hunting instinct.