The Royal Veterinary College’s VetCompass programme has published the results of new research which shows that ownership of Chihuahuas is growing despite the breed being particularly prone to expensive dental problems and obesity.

According to the study1, which looked at Chihuahuas treated in first opinion practice, ownership in the UK has increased over five-fold in the past decade from 1.0% of all puppies born in 2005 to 5.4% in 2016.

However, the study also found the breed was particularly susceptible to a number of health issues, including: dental disease (13.5%), obesity (5.9%) and retained baby teeth (5.7%).

Compared with other dogs, Chihuahuas were also more prone to aggression (4.2%), slipping kneecap (4.0%) and retained testicles (3.9%).

Other findings included:

  • Males are more likely than females to show aggression, heart murmur, ear infection, conjunctivitis and upper respiratory tract infection. There were no disorders that were more common in females.
  • The average adult Chihuahua bodyweight was 3.4kg.
  • The average Chihuahua lifespan was 8.2 years. Females (10.2 years) generally outlived males (6.9 years).
  • The most common causes of Chihuahua deaths were heart disease (18.8%), lower respiratory tract disorder 16.3% and traumatic injury (13.8%).

Dan O’Neill, senior lecturer at the RVC and author of the paper, said: "Chihuahuas are an old breed but the recent craze for them can cause some real welfare issues for this tiny dog. There is increasing evidence that unscrupulous breeders and dealers both inside and outside the UK are cashing in on this trend by making a lot of money but with little regard for the welfare of these puppies and breeding bitches."

Camilla Pegram, VetCompass epidemiologist at the RVC and co-author of the paper said: "Dental disease and retained baby teeth should be recognised as important health concerns for Chihuahuas, with preventative care for dental disease a key topic for discussion between vets and owners. In addition, many of the common or predisposed disorders, such as dental disease, retained baby teeth, sliding kneecap and retained testicle(s), often require surgical intervention. The Chihuahua’s small size increases its anaesthetic risk. Obesity has many detrimental effects, including increased anaesthetic risk, and aggression makes them challenging patients and pets, therefore nutrition, lifestyle and behaviour are also key areas for veterinary-owner discussions."

The full paper is open access:


  1. O'Neill, D.G., Packer, R.M.A., Lobb, M., Church, D.B., Brodbelt, D.C. and Pegram, C. (2020) 'Demography and commonly recorded clinical conditions of Chihuahuas under primary veterinary care in the UK in 2016', BMC Veterinary Research. 

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