Man's best friend is getting smaller

Over the last 28 years, pet owners in Australia have favoured smaller pedigree dogs with shorter and wider heads, according to a study published in the open access journal, Canine Genetics and Epidemiology. The popularity of dogs with short, wide heads could be used to predict the prevalence of diseases typically associated with this head shape, such as the pug and bulldog, and may help the veterinary profession prepare for future caseloads.

The study investigated 180 breeds from the Australian National Kennel Council (ANKC) registration statistics from 1986 to 2013, looking at trends in the demand for Australian purebred dogs of various height, size and head shape. Each breed was assigned to one of four size groups; small (less than 10kg); medium (10kg-25kg); large (25-40kg); and giant (40kg and over). In total, there were data on 54 small breeds; 62 medium breeds; 42 large breeds and 22 giant breeds registered over that time. Over the study period, registration of small and medium breeds increased by 4.2% and 5.3% relative to large breeds, and by 11.0% and 12.1% compared to giant breeds.

Lead researcher, Kendy Teng, from the University of Sydney, Australia, said, "Australians are favouring brachycephalic breeds, dogs with shorter and wider heads, such as the Pug and the French bulldog, more than those with longer and thinner heads. Looking at data spanning 28 years, we found that the demand for smaller dogs has increased every year from 1986."

"Veterinarians are concerned about brachycephalic dogs' welfare, as these breeds commonly suffer from breathing difficulties, skin and eye conditions, and digestive disorders. In New Zealand, brachycephalic breeds are number four of the top five dog breeds considered by veterinarians to be unsuitable for continued breeding due to compromised health and welfare. We expect to see vets in Australia treating more dogs with the conditions described."

The researchers suggest that the change in preferences could reflect shifts in human lifestyle. Dogs are now chosen mainly for companionship, rather than being selected to fulfil certain roles, such as hunting or guarding, for which owners would normally choose larger dogs. The change could also be due to limitations in living space. From 1995 to 2010, most first-time buyers in Australia bought flats or apartments rather than houses. This downsizing could mean that potential owners do not have the space to house a large dog. Current trends may simply reflect the role of fashion. In addition, there is a recognised tendency for dogs with juvenile facial features to elicit more care-giving behaviours from humans, part of the so-called baby schema effect. However, the authors acknowledge that the trends they report could be due to a number of different factors.

This trend is also apparent in the UK, where bulldogs, boxers and pugs have become increasingly popular in recent years. UK kennel club registrations of pugs and bulldogs have climbed from 2004 to 2013, the number of pugs has increased from 1675 in 2004 to 8071 in 2013, and French bulldogs also rose from 350 to 6990. In the US, numbers of bulldogs and French bulldogs registered with the American Kennel Club have increased by 69% and 476% respectively, in the past decade.

The authors note that these results are true for dogs registered with ANKC, and may not be representative of either the purebred or general dog population in Australia.