INDIA: When a rat encounters a piece of cheese, it apparently experiences something like what humans do at a fine symphony concert.
New research shows that rats smell in stereo, much in the way humans hear. Scientists said rats can precisely detect the location of odours by comparing the intensity and the timing of smells arriving in each of their nostrils. The nasal passages in rats send separate signals to the rodents' brains.
"For a rat, each sniff is a perceptually complete snapshot of the olfactory world," noted researchers Raghav Rajan, James P. Clement and Upinder S. Bhalla of the University of Agricultural Science in Bangalore, India.
The researchers conducted experiments that showed rats learned they could get a drink from a water spout on the left or on the right depending on whether researchers provided them with odour trails on one side or the other. When there was no smell, the rats were not able to pick the right spout based on sounds.
Subsequent experiments also showed that when rats were allowed to smell through only one nostril, eliminating the stereo effect, their ability to determine the direction of the odours fell sharply.