Investigating the Life Expectancy at Birth of Companion Dogs in Portugal Using Official National Registry Data

Abstract

This study aimed to provide a comprehensive picture of the life expectancy of dogs in Portugal, focusing on the impact of diverse factors including breed, sex, size, and skull shape. The final dataset, gathering data from the national registry database, consisted of 278,116 dogs with confirmed deaths. The mean lifespan at birth for all the dogs was around 8.91 years, with the female dogs tended to have a similar lifespan to male dogs. The analysis of life expectancy at birth for the 20 most common non-Portuguese breeds and 10 Portuguese breeds revealed that Yorkshire Terriers had the highest life expectancy (10.89 years) and French Bulldogs the lowest (6.27 years). Size and cephalic index were found to be influential factors, with large brachycephalic breeds exhibiting shorter life expectancies and smaller, mesocephalic breeds experiencing longer lifespans. Additionally, the cephalic index had a more substantial impact on life expectancy compared to body size. These findings enhance the understanding of the factors influencing canine longevity and aid in developing strategies to improve the health and lifespan of companion dogs.

Keywords: breed size; canine longevity; companion dogs; life expectancy; skull shape.

Figure 1

Life expectancy for female and male dogs across different ages.

Figure 2

Life expectancy comparison between top three breeds with shorter lifespan (represented by dashed lines) and top three breeds with a longer lifespan (represented by a solid line) across different ages among the 20 most common non-Portuguese dog breeds.

Figure 3

Life expectancy comparison between three Portuguese breeds with shorter lifespans (represented by dashed lines) and three Portuguese breeds with a longer lifespan (represented by a solid line) across different ages.

Figure 4

Plot showing marginal means of life expectancy by body size for each cephalic index.