These infrared pictures show that some mammals keep their nose warm, while some keep them cold. Can you guess which of the noses below belongs to each animal? Oh, and more importantly, can you guess why their noses are hot or cold? You’ll find the answers at the bottom of this post.

ir animal noses rhinaria

Mammal Noses in Infrared. Via Lund University Mammalian Rhinarium Group

The pictures come from scientists at Lund University in Sweden, and it’s not just about curiosity or about taking nice pictures of cute schnozzes – they are actually studying a specialized mammalian nose structure called the rhinarium. The rhinarium is the moist, naked surface around the nostrils of the nose in most mammals. In actual scientific usage it is typically called a “wet snout” or “wet nose” from its moist and shiny appearance.

“We want to know what mammals can do with specialized nose tips,” Lund zoologist Ronald Kröger explains.

A cat’s rhinarium. Via Wiki commons.

Many mammals, like dogs, cats or deer have wet, hairless rhinaria – however, humans don’t. We like our noses dry. The consequence of this is that the nerve interiors of different noses are also almost certainly very different. Kröger and team is trying to find out what role do the rhinaria play in terms of temperature – in other words, what advantages do mammals have from having hot or cold noses.

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Previously, he researched animal vision, but interestingly enough, he got curious about rhinaria when his dog touched him with its cold nose, which made him wonder about its unusual temperature.

“I thought, this is so interesting, we have to know more,” he says.

So far, the team hasn’t published any scientific papers, but they’re well on the way.

The animals above are:

Row 1: dog, horse, sheep, pig, cat, goat
Row 2: rhesus monkey, rat, kinkajou, rabbit, cow, degu
Row 3: zebu, ring-tailed lemur, meerkat, harbor seal, moose, raccoon dog
Row 4: polecat, arctic fox, lynx, raccoon, common eland, human


ir dog nose

Have a look at this dog’s nose as he falls asleep (top row) and then awakes (bottom row). Typically, dogs keep their noses wet a few degrees warmer than the rest of their bodies. However, when they rest, the nose becomes drier and warmer – only to get wetter and colder when they awake.