Ruminations on Canine Nasal Anatomy

Factual Questions
1

I was petting my puppy (4 mo. old black lab/terrier mix) last night and started thinking about his nose. Specifically, the leathery stuff on his snout that surrounds his nostrils. Here are some GQs/thoughts:

  1. Is this stuff skin?

  2. Is this stuff the same as the stuff on the pads of his paws? Obviously, it is not exactly the same, as the paw pads are much rougher/calloused; is it basically the same?

  3. What is the purpose of having such a different material at this specific area of the body?

My thoughts…

  1. I’d say yes. I threw this in for completeness, and to see if anyone wants to argue otherwise.

  2. No clue. I want the SD.

  3. A couple things come to mind here. A dog’s snout is an interesting place. It is obviously related to the sense of smell - does this differentiated tissue aid in smelling? Also, the tip of the snout is vulnerable when in a fight. Is this tissue different for protection? Or something else? Or for no reason?

Replies made directly addressing these points would be nice, but for off-topic discussion, what other animals have interesting different types of skin covering minor portions of their bodies that serve a useful purpose?

2
  1. It’s a differentiated type of skin with secretory glands in it.
  2. All skin is made up of squamous epithelial cells. The look/feel/texture of skin depends on how many layers of cells there are, what kind of glandular tissue is involved, hair absence or presence, and how much keratinization there is. Keratinocytes are dead, dried out squamous skin cells which build up that dead protective layer which is the soles of our feet (or in this case, the dog’s paw pads). Another specialised kind of skin, but skin nonetheless.
  3. Nose skin isn’t all that different, but I guess the reason there is no hair on it is for tactile sensitivity (dogs don’t have fingers to check things out with like we do), the glands are for keeping it in good condition so it doesn’t crack/hurt, and the architecture is probably something to do with efficiently detecting smell. None of the actual smelling is done by the nasal planum.

For the off-topic part- hooves/claws are another specialised kind of skin. They serve the useful purpose of protection of the vulnerable parts of the foot (in hooved animals that do a lot of running) or protection of the whole animal (claws).