What’s the deal with blue tongues?

Blue and blue-black tongues occur in several animals.

Blue-tongued skinks are named after them.

Via Bill Hughes’s Flickr photostream.

Some rattlesnakes have them.

Via The Horned Jack Lizard’s Flickr photostream.

The members of giraffidae, the okapi and the giraffe, have them.

Via djhinrich Flickr photostream.

Via zeandroid’s Flickr photostream.

And it’s one of the most notable features of the chow chow.

Via budak’s Flickr photostream.

I doubt there is a common explanation for all instance of blue tongues. The Wikipedia article on Northern Blue-Tongued Skinks says that they “have a bright blue tongue that is often used to warn off or startle predators.” While it’s clear they’re not closely related at all, it seems like a plausible explanation for the rattlesnake as well, as their “rattles” are also used to warn off predators.

It’s hard to imagine that’s true for the members of giraffidae and the chow chow though, giraffes being so tall it’s difficult to imagine any predators even seeing the tongue, and dogs usually being predators not prey. The page on giraffes on the San Diego Zoo’s website says “some people think the color is to keep the tongue from getting sunburned,” which I guess might be possible, but it doesn’t seem to explain its relative the okapi, which I imagine wouldn’t have too much risk of getting sunburns, as its short enough to get shade from tree cover, and lives in the rainforest, where there often isn’t too much sunlight that reaches the ground anyway. I wasn’t able to find an explanation for the okapi’s tongue color, most sources were more interested in the fact that they were able to lick their own ears.

I wasn’t able to find an explanation for the chow chow either, but I imagine that it’s due to human controlled breeding.

My favorite explanation for all of these tongues though is that they just eat blueberries.

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#1 Grace on 06.20.08 at 10:25 am

That is pleasingly random. I don’t know of any good answer either.

#2 raptorred on 06.27.08 at 2:42 pm

oh man, now I want to know, too :(

#3 inkytwist on 07.08.08 at 11:11 am

Hey, what happened to you? Where’d you go! I miss your posts… Uglorable is such a cool idea.

#4 Libbie on 08.20.08 at 7:29 am

It’s thought that the blue tongues of the giraffidae evolved to help prevent sunburn. After all, that tongue pokes out quite a lot while they’re browsing. I can see how it could be vulnerable to sunburn.

The blue tongue of the chow chow is simply the same dark pigment (eumelanin) that makes the chow chow’s skin black. Many, many dogs have black spots on their tongues and on the roofs of their mouths. You can think of them kind of like birth marks or beauty marks. Chow chows (and shar-peis, which also have blue-black tongues) were just selectively bred to have larger and larger “tongue birth marks” until the entire tongue shows dark in most individuals in the breed. It’s common for dog owners to think that because their dog has a dark tongue or tongue spots that it’s part chow or shar-pei, but in fact pigmented tongues are very common in all breeds.

I used to be a dog trainer and show dog handler, which is why I know so much about dog tongues. Ha ha ha.

#5 Carlos Dan on 01.29.09 at 6:46 am

Excelent article dude! An interesting topic that of blue tongues, always called my attention.
I’m going to quote you in my blog.

#6 Russell on 01.29.09 at 8:48 am

Tounges are blue in larger mammals when vessels run along the insides and veins run along the outside.
Viens are the blue because they de-oxygenated blood back to the heart. It can be to do with cooling down.

I think this information is correct. Me and my friend were arguing about it in a pub once when someone stepped in and set us straight.