Michael Hopkin in Nature:
Researchers in India have discovered that a single sniff is enough for a rat to locate the source of an enticing aroma.
Their work shows that rats can effectively smell in ‘stereo’: their two nostrils work independently in much the same way as our ears, with contrasting signals to the brain creating a spatial understanding of sensory information.
The team at the National Centre for Biological Sciences in Bangalore tested the ability of rats to discriminate between smells coming from their left or their right.
More here.