Land retrievers are more mastiff-like. They’re required to be tough dogs that can handle frigid water and plow through heavy vegetation. As a result (according to “The Dog and it’s Genome”) retrievers are heavier bodied and shorter than pointers are, and have a heavier, more bracoid head.

Morphology, folks. It’s the learning and knowing of organisms and their specific structural features, and at some level, most of us are morphologists because we can tell a hound from a terrier. It’s one of the reasons NPDD harps on “type.” You can see just from the silhouettes in the image the glorious differences in our breeds.