Why do Tiliqua have blue tongues?

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Joseph S.
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Why do Tiliqua have blue tongues?

Post by Joseph S. » April 15th, 2014, 1:47 pm

Are their any actual scientific papers on this at all?

~Joseph

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Sam Sweet
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Re: Why do Tiliqua have blue tongues?

Post by Sam Sweet » April 16th, 2014, 3:20 am

Northern bluetongues are reasonably common in Kakadu NP east of Darwin, and there is a local story on this topic, centered on Koongarra Saddle on the road S of Gubara. A short rock pillar at roadside there is Gurrihdjadjan, Bluetongue Dreaming, with a painting of Gurrih himself. In the beginning when people were animals a big mob was traveling south along the escarpment, having emerged from the sea at Croker Island, and various individuals were directed off to the east and west to create country, people and languages. Gurrih was sent to cross the Mt. Brockman massif at Koongarra, but as he hurried up the low pass he slipped on the flat rocks, fell on his face, and badly bruised his tongue. Embarrased, he "put himself" on the rock pillar, becoming the painting that is the embodiment of all blue-tongued skinks. Now whenever you meet Gurrih in the woods he reminds you to walk carefully on the rocks by showing you what happened to him.

That's one idea. Another possibility is that you might not want to eat something that was so long dead that its swollen, blue tongue was forced out of its mouth by gas buildup in the body cavity.

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Joseph S.
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Re: Why do Tiliqua have blue tongues?

Post by Joseph S. » April 16th, 2014, 11:27 am

Hello Sam,

Haha, love the dreamtime story. Their is at least one more out there I am familiar with.

Imitating the color of a bloated dead thing is interesting-but the rest of the behavior does not seem to match. Otherwise perhaps we'd expect Tiliqua to roll over, musk, and extrude the tongue when provoked. But mimicry need not be very exact-innate aversion of a bright color is all that evolution would need here.

I've heard a couple people suggest that blue-tongues mimic death adders-but they don't have bright blue mouth lining so far as I know.

Also, apparently a couple of related genera have blue tongues but so far as I know do not display(she-oak skink). Then their is Tiliqua(or whatever you want to call it) gerrardi-which starts life with a blue tongue and then loses it.

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Kelly Mc
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Re: Why do Tiliqua have blue tongues?

Post by Kelly Mc » April 16th, 2014, 12:31 pm

Human eyesight is not inclusive of color opsins present in most birds and many reptiles, especially lizards.

Color intensities of lateral spotting, dewlaps, tongues, and other features dont appear to other animals like they do to our limited vision, comparatively.

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moloch
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Re: Why do Tiliqua have blue tongues?

Post by moloch » April 16th, 2014, 3:32 pm

"I'm warning you ... backoff or else!"
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"There, take that! Are you scared yet?"
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chrish
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Re: Why do Tiliqua have blue tongues?

Post by chrish » April 16th, 2014, 6:47 pm

I have always thought the key was the sudden contrast of a bright blue tongue against a relatively bland background. It is the same "shock value" of a Cottonmouth's white mouth lining or the black lining of a Rough Greensnake mouth.

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Kelly Mc
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Re: Why do Tiliqua have blue tongues?

Post by Kelly Mc » April 16th, 2014, 7:33 pm

chrish wrote:I have always thought the key was the sudden contrast of a bright blue tongue against a relatively bland background. It is the same "shock value" of a Cottonmouth's white mouth lining or the black lining of a Rough Greensnake mouth.

Yeah, and I suspect alot of the Flair of these displays are lost on us.. The flash intensities and even the 'color' we see may not be at all what other organisms see.

GeckPhotographer
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Re: Why do Tiliqua have blue tongues?

Post by GeckPhotographer » April 16th, 2014, 7:49 pm

"Also, apparently a couple of related genera have blue tongues but so far as I know do not display(she-oak skink). Then their is Tiliqua(or whatever you want to call it) gerrardi-which starts life with a blue tongue and then loses it."

She-oaks definitely display, thought no all individuals. Some of the displays I've seen from them are far more voracious than any bluetongue. However the displays do have an edge of snake mimicry.

Cyclodomorphus gerrardii for that matter will also display as an adult when it's tongue is pink.

Quite a number of Australian skinks have blue tongues.

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Joseph S.
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Re: Why do Tiliqua have blue tongues?

Post by Joseph S. » April 22nd, 2014, 1:55 pm

Insight is much appreciated!

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jonathan
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Re: Why do Tiliqua have blue tongues?

Post by jonathan » April 23rd, 2014, 3:17 am

Here in India, Common Bronzebacks (Dendrelaphis tristis) have blue tongues, while Painted Bronzebacks (Dendrelaphis pictus) have red tongues. Not sure if there is anything at all purposeful (by which I mean "played a factor in superior survival rates") in that evolutionary difference, or if it just got selected "by accident". I can't imagine much a relation to survival rates due to tongue color for those species.

Here's one of the blue-tongued ones:

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