Two Labradors stand side by side at a park in Bengaluru. One is broad-chested with a thick otter tail, a wide skull, and a calm, heavy gait. The other is narrower, higher on leg, and already scanning the field before its owner has unclipped the leash. Both are registered Labradors. Both are yellow. The difference is not a fluke of individual variation, it is the predictable outcome of roughly a century of selective breeding pulling the same dog in two directions at once.
