Perhaps one of the first things you learned in kindergarten was that you had five senses: sight, taste, smell, hearing, and touch. But the actual number is probably way more than that, maybe in the 30s. And there's a whole lot we don't know about the senses that we do have.
After all, our senses are just the ways we turn the outside world into data for our brains to process. And reality isn't always the way our brain experiences it. The American Museum of Natural History in New York recently opened an entire exhibit titled Our Senses, curated by curator and molecular biologist Rob DeSalle, on display until January 6, 2019, that explores the senses in animals (such as humans) including the ones your teachers may have forgotten or not known about.
Balance is perhaps the most underrated of the non-traditional senses. The ear is filled with fluids operating in three directions, like the x, y and z-axes of a three-dimensional graph. The fluid inside can help the body orient itself and keep you upright in space.
There are other senses, too. Some think blood pressure is a sense, or the need to eat and drink. Going to the bathroom is a sense as well. Imagine if the twist at the end of The Sixth Sense was that Haley Joel Osment needed to go to the bathroom the whole time.
Other senses are just misunderstood. Take taste. You don't actually have a "tongue map" of sweet, salty, sour, bitter, and umami. Instead, there are mushroom-shaped structures called papillae that contain your tongue's chemical detecting taste sensors, the taste buds. Not everyone has the same tasting abilities, and taste can differ based on the density of these papillae on your tongue. Those with a high density of these papillae are considered "supertasters," and might be especially sensitive to alcohol or to bitter flavours like coffee.
You can check yourself to determine what kind of taster you are by dyeing your tongue with grape soda or Kool-Aid powder. Put a hole-punched paper's hole over your tongue's tip and count the white spots -- 30 or more in the hole and you're a supertaster. Less, and you're just a regular taster, or even a non-taster.
Much of your experience of taste is actually flavour, in fact, thanks to chemical sensors in your nose that actually detect smell.
Senses differ between animals too. Carnivorous cats don't taste sugar, for example. Some tastes aren't conserved by evolution when a species no longer needs them, explained DeSalle. And you might think we lag behind dogs when it comes to our sense of smell, but we're actually quite adept smellers if we learn to train ourselves. Other animals hear different pitches higher or lower than we do, see wavelengths of light that we can't, and even perceive the world in slow-motion.
But as humans, it's unlikely that we'll let physical constraints limit what we can sense. DeSalle told the audience, "We can always build something."