Sniffer dogs pass the whiff test for twins

SMALL PRINT:IT SOUNDS like the perfect cover-up: carry out the crime and then blame it on your twin. But such a ruse could be rumbled by highly trained sniffer dogs, according to new findings.

Previous attempts to get sniffer dogs to reliably distinguish between scents taken from identical twins have tended to fall on their snouts.

But the researchers, based in the Czech Republic, reckoned that dog-training may have contributed to inconsistencies in the literature.

So they recruited some top-notch canines for the job: “We hypothesised that police dogs with the highest level of training would be able to distinguish individual scents of monozygotic twins even if they lived together and ate the same food, regardless of any scent differences acquired over their ontogeny,” write the study authors in PLoS One.

They put 10 specially trained police German Shepherd dogs to the test in setups where the dog got to sniff one “starter” scent, then identify its match among several others presented in glass jars. If the dog reckoned it had found a match, it would lie down.

And the pooches aced it: “All dogs in all trials distinguished correctly the scents of identical as well as non-identical twins. All dogs similarly matched positively two scents collected from the same individuals. It seems that by the age of five, specific individual scents of identical twins are recognisable by specially trained German Shepherd dogs. Further research should be focused on the age of the identical twins and whether or when their scents start to differentiate.”