Who's a clever girl!
Whisky — a six-year-old border collie — has learned the names of 90 different toys on her own and can fetch them on request, researchers have found.
The clever canine has learned to differentiate between balls, frisbees, rings, or ropes — and can even categorise new toys into these groups.
When the researchers first met Whisky, she already knew the name of 59 toys, but her owners say that she has now learnt around 31 more.
Whisky may have a little way to go before she breaks the alltime record for the cleverest dog, however. Fellow border collie Chaser, of South Carolina — who was owned by psychologist John Pilley — is said to have learnt more than 1,000 words before she died last year.
'At first it was hard for me to believe that a dog learned the name of so many toys, but after several days of rigorous testing, I had to change my mind,' says lead researcher Claudia Fugazza of the Eötvös Loránd University in Hungary.
'We noticed that, among her toys, Whisky had several exemplars belonging to one of 4 categories: she had 10 different balls, 7 different rings, 4 different ropes and 4 different frisbees,' the animal behaviour expert added.
The owners refer to each of these toys by both an adjective and a category name — for instance, the 'small frisbee' or the 'colourful ring'.
Whisky's owners had not explicitly trained the clever collie to learn different categories — she appeared to have picked them up in the course of play-centred interactions with her humans.
'This provided us a rare opportunity: testing whether a dog had spontaneously formed some mental categories, simply by being exposed to their exemplars — pretty much like a human child would do,' Dr Fugazza said.
'Most studies on the ability of non-human animals to categorise are conducted after the subjects are extensively trained to recognise categories with a given set of exemplars,' added paper co- author and animal behaviour expert Ádám Miklósi.
'Only after reaching the predetermined criterion, they are tested on their ability to categorise novel items belonging to those learned categories.'
To put Whisky to the test, researchers presented her with sets of four new toys that she had never seen previously — one from each of the four categories of balls, frisbees, rings and ropes. Whisky's owners then asked the dog to fetch a toy from a given category — for example by saying 'bring me a ring'.
The researchers found that Whisky chose the correct category of toy from the new playthings more often than pure chance should allow. To make sure that Whisky wasn't selecting the toys based on visual cues from her owner — such as pointing or looking at the correct item — the researchers placed the toys out of sight of her owner.
Researchers say Whisky's skills are similar to those of young babies when learning their first words. The full findings of the study were published in the journal Scientific Reports.