Photo: Mammals Have "Alarm Detectors" in Noses



Long nerve fibers connect a mouse's olfactory bulb—the green circle seen above—to a ball of microscopic cells called the Grueneberg ganglion at the tip of its nose.

The tiny ganglion, long a mystery to scientists, is actually a sensor used to pick up chemical warning signals sent by fellow animals in distress, according to a study released in August 2008.

Image © Science/AAAS


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