To enable the dog to climb, descend, and brake on these cliffs, unique structural characteristics have evolved and must be present
as they define this breed: a minimum of six toes on each foot and elongated rear foot pads; an elastic neck that allows the head to bend backward to touch the
spine, letting the dog turn around in narrow puffin bird caves; and shoulders flexible enough to allow the front legs to extend flat to the side in order to
hug the cliffs.