Rats can home in on smells using a method similar to the stereo processing of sounds, scientists say.

Indian experts found 90% of neurons in the olfactory
bulb of the rodent’s brain respond differently to smells coming from
the left and right.

Details of the study appear in the latest issue of the journal Science.

The rats needed only one or two sniffs to accurately
locate the source of an odour, the University of Agricultural Science,
Bangalore, team reports.

For rats, "each sniff is a perceptually complete
snapshot of the olfactory world, including both odour identity and
stereo-based location," Raghav Rajan and colleagues write in Science.

The researchers got lab rats to stick their noses in
holes in their cages to pick up odours sprayed from either the left or
the right.

If the smell came from the left, the rats would receive
a water reward by licking the spout on the left. The same would apply
if the smell came from the right.

The rats were able to accurately determine which direction the odour came from in as little as 50 milliseconds.

The researchers say the rat’s stereo sense of smell
gives it an evolutionary advantage: allowing it to locate food or
predators more quickly and precisely.

More here.