Significant variation in lifespan between dog breeds reflects underlying health differences, with welfare implications for individual dogs and responsibilities for breeders, owners, and veterinarians.
Breed lifespan differences are not simply biological inevitabilities but reflect breeding decisions that have welfare consequences for millions of dogs. A Great Dane expected to live 7 years experiences a life compressed into a shorter span with more years spent managing age-related decline relative to its total lifespan. Giant breed dogs experience musculoskeletal deterioration, cardiac disease, and cancer at ages that owners and veterinarians may not recognise as geriatric. Flat-faced breeds combine shorter lifespans with respiratory compromise, further compressing quality of life. These outcomes result from selection choices that prioritise appearance and size over health and longevity. Breed reform movements, outcrossing programmes, and health-prioritised breeding can shift these trajectories within relatively few generations.