© homer4k / B. J. BumgarnerDogs sniff the breath of other dogs to work out where to find food
They may not be as discerning as a Michelin Guide, but dogs decide where to look for food by sniffing the breath of others.

When tasked with finding a hidden treat, pet dogs heed the advice of another pup that has faced the same challenge.

Such behaviour is common in the animal world. Rats, gerbils, chickens and monkeys are just a few of the creatures known to direct friends and family members to a nearby meal via scent or sound. Chimpanzees tap the shoulders or glare at other chimps while leading them to a treat; the cunning apes also sometimes employ misinformation to keep a food stash secret.

Perhaps most famously, honeybees tell their hive-mates where to find nectar via elaborately choreographed "waggle dances".

Such evidence suggests that domestic dogs should also learn where to find food by communicating with their fellows, yet evidence has been tough to come by.

Scavenger hunt

"They're scavengers," says Clive Wynne, a psychologist at the University of Florida in Gainesville. "It would seem to be advantageous for them to pay attention to where another dog finds a titbit and go after it."

© Kristi Miller/Newspix / Rex FeaturesSniff... Sniff... Ah, the food's behind the tree
To see if dogs can actually do this, Marianne Heberlein at the Institute of Zoology in Zurich, Switzerland set dogs loose to search for food behind one of four barriers. The dogs had been shown where the treat was beforehand, so they always went to the same place.

However, for some of the 13 dogs, Heberlein had taken the treat away and the dog found nothing to eat.

Snout sniff

Both the tricked and successful dogs were then allowed to interact with 11 dogs from a second group, none of which knew where the treats were. Sometimes they would sniff each other's snouts. Each of the dogs from the second group was then allowed to search for food behind the barriers.

If the first dog's search for food had turned up nothing, the second dog showed no preference for any corner. However, in the trials where the first pooch found food, the second dog tended to visit that corner first - especially if the dog had caught a whiff of the other's breath.

This suggests that the second dog based its search on whether or not it smelled food on the breath of the first dog, Heberlein says. She also stocked treats hidden underneath a box in each corner, so the dogs couldn't rely on smell to decide which corner to explore first.

"It's a smart paper and it gets at an aspect of the behaviour more from the dog's point of view," says Wynne.

Yet in spite of their popularity and demonstrated cognitive prowess with humans, researchers know surprisingly little else about dog-to-dog communication. "We have not found a waggle dance," Wynne says.

Journal reference: Animal Behaviour, DOI: link