The eyes are round and dark, which is in contrast to the triangular or slanted composition of their American counterparts. The British Kennel Club standard is used in all countries except the US and Canada. Golden retrievers have muscular bodies with great endurance, owing to their origins as hunting and gundogs. As a Golden grows older, its coat can become darker or lighter, along with a noticeable whitening of the fur on and around the muzzle.