Scientists previously believed that whales and dolphins did not have the ability to smell, but one group of researchers have found olfactory receptors inside the snout of a bowhead whale. Professor Hans Thewissen of the Northeastern Ohio Universities College of Medicine and his Japanese and Alaskan colleagues made the discovery while dissecting bowhead brain parts.
The bowhead whale had been killed during a bi-annual subsistence hunt in Alaska, and Thewissen and team were given the remains to evaluate the amount of brain space a whale brain occupies. "Upon taking a brain out, I noticed that there were olfactory tracts, which, in other mammals, connect the brain to the nose," stated Thewissen. He followed the tracts and made a startling discovery.
It was believed that whales could not smell, since everything they would want to sniff out is underneath the water. Since the act of smelling is literally the act of smelling airborne molecules, having olfactory tracts didn't seem to make much sense. Further, in other cetacean species, the actual "hardware" for olfaction is missing entirely.
As it turns out, bowhead whales have both a large olfactory bulb, and the necessary olfactory receptor proteins similar to the olfactory hardware of other smelling animals. Bowhead whales also have separate nostrils, another characteristic that separates them from most other whales. Separate nostrils mean that bowhead whales may be able to sense the direction that the smell is coming from.
"It is remarkable that this animal, which appears to have very little use for olfaction, retained that sense," says Thewissen. "We speculate that they are actually able to smell krill and may use this to locate their prey. Krill smells like boiled cabbage."