Toothed whales, such as belugas, “hear” through their lower jaws. ©Alexander de Vries

You’ve probably heard about people who “see” the color blue when they hear a certain note played on a piano, for instance, or experience a sweet “taste” in their mouths when they touch a peach. While once these odd sensations were written off purely as mental associations or vivid imaginations, today the phenomenon is recognized as real. It even has a name: “synesthesia” (from the Greek roots syn, meaning “together,” and aisthesis, or “perception”). Synesthesia, then, is diagnosed when an otherwise normal person experiences the blending of two or more senses.

It’s becoming clear, as we continue to learn more and more about the functioning of the human brain, that our senses are not the five, rigid domains we once thought they were. They may flow into each other, mix themselves up and even create brand-new ones, such as when we describe people as having a “sixth sense,” or a strong intuition. In fact, the idea of five senses now seems to be an old-fashioned way of describing our multisensory system.

But I think there’s another variant to this many-pronged theory that is even more remarkable, and it involves the place of origin for all of these perceptions. And, once again, it is the nonhuman animals that are modeling the way.


Some people can “smell” sounds or “taste” colors.

Good listeners

In the low light and the murkiness of the world’s oceans, whales have trouble seeing clearly. Developing senses other than sight became crucial for cetaceans.

In fact, studies of beluga whales have shown that they can hear sounds in the range of 1.2 to 120 kHz, with a peak sensitivity of about 10 to 75 kHz. In comparison, the average hearing range for humans is about 0.02 to 20 kHz. Whales have even been known to react to the click of an underwater camera.

It’s believed that belugas and other toothed whales “hear” so exceptionally well through their lower jaw, which is wide and hollow at the base where it hinges with the skull. Within this very thin, hollow bone is a fat deposit that extends back toward the auditory bulla (or ear-bone complex). Sounds are received and conducted through this lower jawbone to the middle ear bones and from there to the hearing centers of the brain.

Whales and dolphins have even been known to react to the click of a camera. ©Candice Gaukel Andrews

Seventh sense

The phenomenon of synesthesia and the fact that toothed whales “hear” in their bones makes me wonder if our skeletons aren’t the conduits for a lot more than we think. Take, for example, the devastating Indian Ocean tsunami that hit in December 2004. It was reported that on India’s Andaman Islands, Jarawa people sensed the approaching wave long before lofty waters struck the coasts. They fled to higher ground. How did they know what was coming? Some postulate that they became aware of the impending danger from the frantic cries of birds or noticed changes in marine animals’ behavior. Or it could have been the sum of all of their senses, combined with their tribal knowledge of nature. I think it may have been a “feeling,” a sensory perception that something was emanating from the earth and vibrating up through the soles of their feet into their very cores.

In his new book, The Nature Principle, Richard Louv references an 18-month study of 800 military personnel. It found that the best roadside bomb detectors (other than dogs) were rural people—those who’d grown up hunting turkey or deer in the woods—along with those from tough, urban neighborhoods where it’s equally important to be alert. It would seem that people from these types of backgrounds have developed a new sense, one—for now—without a name.

Perhaps that old saying “I’ve got a feeling in my bones” is more prophetic than we realize. How many times have you “sensed” something that can’t fit into the hearing, seeing, tasting, touching or smelling categories? Perhaps the “seventh” sense—as the Jarawa and some hunting and urban Americans know—is a feeling for imminent adventures, rising in your bones.

Here’s to finding your true places and natural habitats,