Street dogs in India appear to love yellow. In an experiment, the free-ranging canines approached an empty yellow bowl around three times more than a nearby blue or grey bowl, even when those other bowls held food.
The findings suggest that dogs could have an innate attraction to yellow colouring – or possibly that they recognise yellow as the colour of people’s thrown-out food, says at the Indian Institute of Science Education and Research in Kolkata.
“I have a feeling that this preference got heightened with dogs’ co-evolution with humans, especially in India, where we use a lot of spices in our food and all the garbage they’re scavenging is loaded with turmeric,” says Bhadra. “Looking for yellow might have an ecological advantage for them.”
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Dogs’ colour vision is more limited than humans’, making it harder for them to distinguish red, yellow and green. While there have been many studies on their colour discrimination, less is known about their colour preferences.
To find out more, Bhadra and her colleagues ran a series of experiments with 458 free-ranging dogs from Kolkata and the surrounding area. First, they set three terracotta bowls – painted with golden yellow, Prussian blue and grey acrylics – about 2 metres in front of each dog in a random order. Sometimes they all contained a chunk of dog biscuit and sometimes all were empty. Overall, the dogs went for the yellow bowl more than 50 per cent of the time and the grey or blue bowl only about 25 per cent of the time each.
In another experiment, the researchers offered the dogs either an empty yellow bowl or a grey bowl, sometimes containing a chunk of dog biscuit and sometimes filled to the rim with raw chicken. In both cases, the dogs “bee-lined” to the yellow bowl about 77 per cent of the time, and chose the grey one 22 per cent of the time, the researchers report. One dog even pawed at and chewed on the yellow bowl and then approached the researcher before finally giving up and checking the grey bowl.
Aside from the possible appeal of turmeric, dogs might be attracted to yellow because they would see reds and pinks – the colours of blood and meat – in shades of yellow as well.
Bhandra’s team is to find out if dogs there show a similar preference, and she hopes dog behaviourists in other countries will follow suit.
Animal Cognition
