Why are dogs’
and cats’ noses wet?

I thought that it would be easy to find an answer to that question. It isn’t. A book on a lot of hard-to-answer questions has been written—and with a title exactly the same as your question. The author couldn’t find a very good answer either.

Here’s what I did find out. The skin covering the dog’s nose is special. It has no hair follicles that make hairs and no sweat glands. So the nose is not wet by sweat. I couldn’t find reference to any special glands producing fluid in the nose.

When a dog is panting, it breathes in, mostly through the nose, and breathes out, mostly through the mouth. However, in quiet breathing, much of the breathed-out air is warm and very humid, and there is likely to be condensation if the outside air is cooler. That may help to keep the nose wet. And you may have noticed that dogs often lick their noses with their tongues. I think that if you could lick your nose that way, your nose might be wet, too.

I think that answering your question may be difficult just because there are several parts to the answer.