Upon careful examination of my cat’s nose, I have noticed that 1) it is covered by thousands of small, uniform bumps, and 2) it is kept moist at all times with a coat of saliva, which is replenished periodically by the tongue. Having owned a dog, I can make similar observations about the canine nose. And although I have not yet had the opportunity to observe a bear nose at close range, photographs indicate to me that the ursine schnozzle is similar enough in appearance to the nose of a dog that I can safely extend my generalization to include bears along with cats and dogs.
After a bit of research, I stumbled across several references to this fleshy nose pad in the literature. It is usually referred to as a “rhinarium,” and its purpose is often described as relating to the sense of smell. Unfortunately, I cannot locate more specific information on the rhinarium’s function.
Okay, people. No holds barred. Cut to the chase. Tell me everything you know about the rhinarium, its function, and its evolutionary history. Don’t be shy, I can handle it. What are those little bumps? Are they some kind of taste bud? Why must the rhinarium be kept moist? I have heard that one way to gauge the health of a dog is to feel its nose; apparently a perpetually dry rhinarium can indicate some kinds of sickness. And what’s that little seam down the middle? I’m guessing it’s a channel for excess saliva or mucous to run back into the mouth, although I have never seen it used specifically for this purpose. Why is the pad often black in color? To absorb heat? To confuse potential predators? Why don’t humans have rhinariums? Am I missing something because the skin on my nose is indistinct from the skin on the rest of my body?
I would greatly appreciate any information you can offer about this enigmatic structure.
