Do we know if there are any senses that we lack the organs to experience?

General Questions
#1

This is a bit hard to articulate, so I apologize for maybe not describing it as well as I’d like:

We understand sight because we have eyes. We know what sound is because we have ears. We know taste because we have taste buds. But is it possible that any given object (say, a strawberry, a piece of plastic, a leather shoe, anything) has other unique qualities that we simply don’t have the sensory organs to know about? Have we been given indications that there might be other sensory stimuli like sight, sound, and taste that might be out there but that we don’t have the sense organs to know or experience? Have any animals been recognized to experience phenomena that we as humans don’t know about? And is it even possible for us to identify an animal’s ability to detect a phenomena that we lack the ability to experience firsthand? And would we be able to describe this phenomena meaningfully anyway?

#2

We know there are radio waves, but we don’t directly sense them.

#3

Bats have sonar (which, though based on sound, is not the same thing as hearing). Insects can see ultraviolet. There are doubtless other examples.

#4

I assume you don’t count stimuli that is out of the range or precision that we can sense (i.e. high-pitched sounds we can’t hear, light spectrums we can’t see, textures too fine for us to feel, etc.)

Aside from that, the first thing that came to mind was radiation. As far as I know, humans aren’t capable of directly sensing it, but of course we’ve developed technologies that detect radiation for us.

#5

We can’t directly sense magnetic fields.

#6

It is a fine and thought-provoking question. I know this because I asked it myself once. The responses were failry good.

http://boards.straightdope.com/sdmb/showthread.php?t=279793&highlight=senses

#7

Well, we can, but only within the visible light spectrum.

#8

Yes, particularly around electricity in fish.

From here:

Crocodiles and alligators have integumentary dense organs, though no one knows yet exactly what they do. They’re located on the upper jaw, lower jaw and head, and extend elsewhere in some species. They seem to be used to pick up on pressure changes, underwater prey detection, and may be sensitive to changes in salt level of the water.

#9

http://en.wikipedia.org/wiki/Electroception

#10

I’ve heard of people having small magnets surgically implanted into their hands/body. Apparently, after only a short while they begin to “sense” magnetic fields and proximty to certain metals. Of course this is still technically the tactile sense since what they’re really feeling is the slight pull of the magnets on their tissue. However, some have described it as approaching the feeling of a completely different, innate sense.

Sorry, can’t find a relevant link ATM.

#11

Lots of animals have specialized “touch” organs that sense air or water currents. Most fish have a lateral line, which is a depression lined with tiny hairs running down each side. Changes in water pressure move the hairs, this is how blind cave fish avoid bumping into the side of the fishtank.

Lots of mammals, insects and other animals have sensory hairs and whiskers that extend their sense of touch.

And of course, humans famously have many “hidden” senses. Sense of balance provided by the semicirular canals. Sense of proprioception. And probably some others that we don’t quite understand yet. Read Oliver Sacks’ book “The Man Who Mistook His Wife For A Hat” for many case histories of people with disorders of these hidden senses.

#12

Would ‘homing’ as evidenced in homing pigeons count as a sense? Some birds have the ability to return to their nesting habitat even after traveling long distances.

#13

There’s an infinite number of molecules that we can’t smell or touch. Or can’t distinguish between by taste or smell.

#14

Hm. I’m not sure if I’m satisfied with the responses. I posed this question to my girlfriend and she said, “snakes have receptors that can sense heat.” At first I was satisfied, but then I thought about it and realized that I can sense heat, and moreover, I know what heat is. I know what radiation is. And I know what electricity is. We can define those relatively easily… but try to define taste or sight and it’s not so easy. I was wondering more about phenomena like the latter ones, which I feel are somehow different than radiation or electricity or sonar. How, I’m not exactly sure.

The responses here explain about how animals are able to sense the magnitude of known phenomena (electricity or radiation), but I’m more curious about whether they can experience sensory stimuli similar to taste and sound, senses that don’t really involve magnitude. You wouldn’t say that you ‘see’ something strongly, or ‘taste’ something strongly. Either you taste it or you don’t. It’s a binary that describes the experience of an empirical quality of something, and it also so happens that these phenomena are things that we can experience, but not adequately or accurately describe in scientific terms (what is ‘sight’?, what is ‘taste’?).

Perhaps I am wrong in considering radiation in a separate category from taste… but why do I feel like they are incommensurable?

And do objects have a unique ‘sonar’ quality? I was under the impression that this is more of a navigational tool using the patterns of bouncing waves, not really a new sense, per se.

#15

There is some reason to believe they use plain old landmark recognition. (Short version: scientists tracked a bunch of homing pigeons via satellite and found the birds basically followed roads and other landmarks).

Linky to BBC

#16

I saw this a while ago, which seems to be just the thing. (Warning - pics of minor surgery + some blood).

I think I’d like to get some myself if they work out the problems.

#17

This is a reverse answer to the OP’s question. I’m not sure if animals can sense the passing of time as well as humans do. And there’s consciousness amd abstract thinking. That could count as a sense; a sense for abstract concepts that can’t be sensed by most animals.

#18

But what does it mean to “see” something?

You start with a nerve cell sensitive to electromagnetic radiation of a particular band of wavelengths. If enough photons strike enough photosensitive chemicals and convert them to another form, the nerve cell discharges which tells the “brain” that a certain amount of light was present. Put an array of those sensors and you’ve got a simple eye that can detect light and dark, even more and the eye can detect movement. Put a lens on a large array of these cells and you’ve got a real eye that can detect images. Feed the output of the eye into a complex processing center and you’ve got SIGHT.

Sight is easy to understand. Humans have thousands or millions of sensory nerves feeding information into our visual centers, but lots of other animals have very simple eyes that started as something not much different than skin that can sense heat. It’s a mistake to imagine that we just open our eyes and percieve reality unmediated. The human eye doesn’t see what you think it sees, and this can be demonstrated by all the various optical illusions you see. Blind spots that you can’t “see”. Persistance of vision. Color perception influenced by dozens of different things. And on and on. Try looking at footage from a shaky handheld camera and you’ll get sea-sick…but the guy who took that footage while looking through that camera viewfinder was NOT seasick…in fact he might not have even noticed that the camera was shaking. You see a lot less than you think you do, you can only see a very small part of your visual field clearly…but it seems like you can see everything clearly because every time you look at something it’s clear! Your brain fills in an almost unbelievable amount of information, combines it all into a whole, and you have a sense of just looking out and seeing things. But that’s not really happening!

Same thing with hearing. Hearing is just an elaboration of the sense of touch, just like a cat’s whiskers. Smell is trickier, humans have a very poor sense of smell, but you’ve got an array of chemosensitive nerves in your nose, and when enough of the correct aerosolized molecule binds with the chemical receptors in the olfactory receptor nerves the nerve discharges.

So a radiation sensor, or an electrical sensor, or a chemical sensor, or an x-ray sensor, or an N-ray sensor would be the same thing. The nerve cell is sensitive to stimulus N, enough of stimulus N and it discharges. This is how all senses work. It just happens that our sensors and processors for electromagnetic radiation in the visible wavelengths has been developed to an incredible degree over the last 650 million years of multicellular life.

#19

I wonder if electric eels can? Or any known animal?

#20

Magnetic field != electromagnetic radiation.