New research from the Royal Veterinary College has revealed that giant dog breeds in the UK live substantially shorter lives than the general dog population and experience higher levels of some disorders1, raising concerns about the welfare impacts of breeding for extreme size.

For the research, the RVC’s VetCompass Programme analysed anonymised veterinary records from 2.25 million dogs attending UK primary-care veterinary practices during 2019.

From this population, researchers identified 28,345 giant dogs and examined their demographic data, disorder frequency and lifespan records.

The study also involved a detailed manual review of clinical records from a random sample of more than 4,300 giant dogs to assess the most common health disorders and causes of death.

The data showed that the average lifespan of giant dogs was 8.9 years.

This is more than three years shorter than the average lifespan previously reported within VetCompass for dogs overall in England.

The RVC says this finding aligns with other research reported in many countries that more rapid growth in giant dogs leads to more rapid ageing.

The findings also showed that almost three-quarters (73.8%) of giant dogs had at least one disorder recorded annually, significantly higher than the average for all dog breeds (65.8%) within VetCompass.

The most common general groups of disorders overall were skin disorders, musculoskeletal disease and ear disease.

The most common specific diseases were ear infections (8.2%), overweight or obesity (8.0%) and aggression (5.6%).

The frequency of aggression in these giant breeds was more than double the 2.2% level recorded in dogs overall.

Additional findings included:

  • The most common giant dog breeds in the UK were the Dogue de Bordeaux, Alaskan Malamute and Akita.
  • Female giant dogs lived 0.8 years longer on average than males (9.3 years compared to 8.5 years). So, acquiring a female giant breed dog could offer the possibility to owners of a longer life in their new dog.
  • Some giant breeds showed extremely short average lifespans, including Tibetan Mastiffs at just 4.8 years.
  • Cancer was identified as the leading cause of death in giant dogs overall.
  • Great Danes (60.5kg), Irish Wolfhounds (64.0kg) and Saint Bernards (65.1kg) were the heaviest of the 29 giant breeds recorded.

Professor Dan O’Neill, Professor of Companion Animal Epidemiology at the RVC and lead author of the paper, said: “Humanity has reshaped the domestic dog into the most physically diverse mammalian species on earth to create over 1,200 distinct dog breeds.

"Among these, the giant dog breeds can offer wonderful companionship for humans, but our findings suggest that the lifespan and welfare costs for these dogs, linked to their extreme body size, are substantial.

“The relatively short lives of giant dogs compared to the wider dog population should prompt wider discussion on the welfare limits of selective breeding towards extreme giantism.

"To protect these cherished breeds and make them sustainable for the future, moving towards more moderate body sizes within these breeds may help to improve both the quality and length of life for these dogs, while still giving owners a fulfilling dog-ownership experience.”

Reference

  1. O’Neill, D.G., Curtis, T.J., York, G.O.J. et al. Giant dog breeds under primary veterinary care in the UK: demography, common disorders and mortality. Companion Anim. Health Genet. 13, 4 (2026). https://doi.org/10.1186/s40575-026-00152-7