Which dog breeds live the lingest and are the best behaved?
Are you a canine champion of the small and fluffy Shih Tzu? The large and in charge Great Dane? Or a marvelous mutt?
Though superficial aesthetic traits have guided the development of modern dog breeds for the last 200 hundred years, they might not be the most important factor in choosing a canine companion.
Researchers have turned their attention to a couple of questions important to everyone with a furry companion: which breeds have the longest life expectancy? Or does breed predict behaviour?
According to a new study, Jack Russell terriers and Yorkshire terriers have the highest life expectancy of dog breeds in the UK, while flat-faced breeds have some of the lowest.
But for those besotted by pugnacious pugs and bulldogs, a genetic study of more than 2,000 dogs suggests that breed alone is a poor predictor of dog behaviour. The findings subvert stereotypes about dog breeds as to why certain breeds are more aggressive.
Live long and prosper
A team of researchers have analysed 30,563 records of dog deaths from veterinary practices across the UK between 2016 and 2020. They were able to calculate the life expectancy of 18 dog breeds and a group of mixed-breed dogs by constructing life tables which show, for each age, the probability that a breed will die before their next birthday. Unexpectedly, life tables varied widely between breeds.
Breed is not a good predictor of behaviour
Despite widely held assumptions about certain dog breeds and their temperaments, there is a lack of genetic research linking breed and behaviour.
Now, bioinformatics researchers have used genome wide association studies to search for common genetic variations that could predict specific behavioural traits in 2,155 purebred and mixed-breed dogs.
They combined this data with 18,385 pet-owner surveys from Darwin’s Ark, and identified 11 genetic loci that are strongly associated with behaviour. But none were specific to breed.
According to the findings, breed only explains 9% of the behavioural variation in individual dogs, and for certain behavioural traits and survey items, age or dog sex were the best predictors instead.
The majority of behaviors in modern dog breeds likely come from thousands of years of evolution, from wolves to wild canine, to domesticated dogs, and finally to modern breeds. And these heritable traits predate the concept of modern dog breeds by thousands of years.
