Why chams lick lips

[Metric]

"Chameleons do have taste buds!"

Not sure how reputable that is, seeing as there is really no further info.

http://webhome.idirect.com/~chameleon/owners/chapter6-sub1.html

13th point.

 

[PantherVeileD]

They stick their tongue first to aim..Then retract and spit their tongue , WHAM!! Just like playing dart.. Stick it out to aim pull back and throw..

Of coarse they have taste buds...

Also they can see colors as well!!

 

[Chris Anderson]

The chameleon tongue is actually fairly complex. In general, its function is not directly for tasting but rather for feeding/drinking and picking up chemical ques which are analyzed by other receptors in the mouth. Chameleons are known to touch new branches with the tip of their tongues (which are actually forked much like monitors and snakes). It hasn't been explicitly proven but it is likely that this behavior is actually an effort to pick up chemical ques in an effort to taste a new territory, possibly for the presence of other chameleons. It is speculated that males will often rub their vent or the secretions from their temporal gland on branches, possibly to mark territory. These chemical ques are transferred and deciphered by the Jacobson's Organ. The presence of actual taste buds is another story. Often lizards will have taste receptors on the lining of the mouth but it is unclear if chameleons are included in this group or if taste information is also analyzed by the Jacobson's Organ (there is conflicting literature). In either case, chameleons are able to gather information on "taste" from the prey they are eating and there is likely integration of these signals with the brain about whether or not the prey item is safe, etc. Some feeders are surely like "treats" to them and based on the feeder items that chameleon tend to get hooked on (waxworms, mealworms, etc.), it is not necessarily related to regulating a healthy intake of food at all. There have been studies on prey preference with novel prey items and as you suspected, novel prey are more "exciting" to them.

As for the licking their lips, moving their tongue around and protruding their tongue out slightly before they feed, this likely has a couple functions. First, because of the mechanism of tongue projection, the tongue must be well lubricated in order for friction to be minimized and for tongue projection to occur correctly. The observed behavior likely increases the lubrication of the tongue for this. Further, prey prehension is achieved through a combination of mechanical grasping, suction and adhesion. Is it possible that these movements of the tongue help stimulate the mucosal lining of the tongue pad to excrete adhesive mucous. Finally, it could be an attempt to collect chemical ques from the air when it is stimulated to feed (smell the air, if you will). Likely, it is a combination of these things.

Chameleons don't exactly stretch their tongue to prepare it for use and the tongue protrusion and retraction prior to projection is not really for aiming. While aiming is occurring while the chameleon does this, it is actually a continual thing that is going on until the tongue is actually launched. What is happening is the chameleon's accelerator muscle in the tongue, the muscle responsible for loading the forces needed to project the tongue, is slowly activating and building up energy into an elastic storage mechanism (similar to pulling back a rubber band or a bow-and-arrow). Once this energy is stored, it can be quickly released resulting in tongue projection that is faster then any known muscle.

Docility - As a scientist, let me tell you that you are highly misinformed about the importance of many of the studies you are mocking. Fruit fly breeding projects, while expensive are some of the most beneficial studies to the general human population of any scientific research. These studies help advance medical research and protect multi-billion dollar agricultural interests in ways you couldn't even begin to fathom. Sea Salmon studies monitor the health of fisheries and species that are in danger of extinction due to human disturbances. Such studies are important to jobs, industry and wildlife and in many cases are mandated under the federal laws of the endangered species act. My point is, if it wasn't for people like me and other scientists "wast[ing] money on such stupid crap," you'd be living in a third world country without many of the medical and food resources that you take for granted every day, let alone the higher number of extinct species.

Chris

 

[jojackson]

Chris, thankyou for one of the most informative posts Ive read in some time.

There have been studies on prey preference with novel prey items and as you suspected, novel prey are more "exciting" to them.

Im guessing these findings were somewhat expected, but Im wondering if nutritional value selection, over a reasonable period of time were not the direct focus of the study?
more behavioural investigation?
Are you aware of any study either completed or ongoing where my suggestion was the primary focus? Particularly with natural (endemic) prey for a given species?
I know such a leap is hardly scientific thinking, but now the idea is playing on my mind

Its been claimed certain mammals, primates granted, will be selective with food at certain times, not related to seasonal or geographic availabilty, for example, a pegnant female showing prefrence for particular food types despite the availabilty of different types (fruits/plants, in some instances, more protein) and so on.
We can assume the animal has no idea of the nutritional content as opposed to another, yet it seems to instinctively know what it needs. It seems logical to assume taste may play a part?

My curiosity lies in weather reptiles (other than snakes), display similar prefrences and if so why. Seasonal prefrences have ofcourse generally a good reason, one example may be snakes that prey on tree frog eggs. This I assume would occure in an areas natural rainy season when the frogs are producing eggs, the rest of the year this wouldnt be available.

The logic half of me says, reptiles live a life of eat and be eaten and much of their time is spent avoiding predators, most are opportunistic feeders, which wouldnt seem to leave much time for 'shopping' so to speak

I guess its just that chameleons/d3 /uv basking study amazed the heck out of me and inspired considerable wonder. Afterall, how does the chameleon 'know' its d3 is depleted in the first place? This was the question that made me assume UV absorbtion was simply
incidental bonus to thermoregulation. (dare I say 'Intelligent design' )

Another question is how chameleons make the link between the color they see (branch they're hiding on) and the changes needed to the chromataphores to match it, and to what degree to match it? [studies that showed they made more effort to closely match camouglage to hide from predators whos color vision was better, (birds) than from those that were not so good (snakes)]
(ok heres evolution/adaption, but still, how do they judge the hue, the tone, the degree of change?)

The mysterious chameleon! Thank god for scientist like you who also want to know!
I missed my calling I think!

 

[hallenhe]

I have not done anything that could remotely be deemed a scientifically rigorous study (no replicates, for one thing), but I did once offer Thaxter a sampling of every type of feeder insect we had in the house, all in the same box. He ultimately ate all except one waxworm; preference was clearly ranked in terms of wiggliness (but this was a chameleon who had been eating regularly, was presumably under no nutrient limitation, etc.).

I notice the slight forking of the tongue regularly as Thaxter "tastes" the surfaces he marches along. Some places get tasted almost routinely, others much more sporadically. When he touches his tongue to my arm in this "tasting" mode, it is not at all sticky, unlike when he inadvertently shoots me when trying for a hand-held bug. I have associated the tasting with the (very deliberate) face-rubbing he also displays as he marches about (the temporal gland secretions Chris mentioned?). I appreciate your input, Chris, as I've been curious about the chameleon sense of taste ever since reading in Vitt and Pianka's lizard book that lizards showing the greatest adaptations of the tongue for food manipulation seem to have a corresponding increase in sense of taste and smell.

 

[jojackson]

I did search some, I found this abstract from a study anoles (tongue flicking/sensory )

http://content.karger.com/ProdukteD...e=233905&ProduktNr=223831&filename=113865.pdf

Nothing specifically about taste though as related to chams specifically.. Also this breif book preveiw (mentions lizard tongue functions)

http://books.google.com.au/books?id...vfDVBw&sa=X&oi=book_result&ct=result&resnum=2

preference was clearly ranked in terms of wiggliness

Thats intresting, makes me wonder if prey movement patterns play a greater part than thought, ie, flying bugs that land where they can be 'zapped' and slow movers (mantids) over running bugs
and hoppers that would tend to more often escape. Chams eyesight seems to be intrisinctly vital to feeding success, so perhaps pattern recognition is a major player? makes me think the survival rate among chams suffering the loss of an eye (failed predation) for example must be quite low, atleast you'd think so, since binocular focus is important.

More and more questions! AArrrrgh! I knew the 'Mad Scientist' Humour must have a grain of truth to it! Now we know how it originated.

 

[GooglezNvincent]

This is facinating, but i do have a question, how sure are you that they lick vines for chemical ques, i always though that it meant they were thirsty, so everytime they licked a vine or whatever i would spry their cage and nearly everytime they would start drinking. You think it is just a coinsedence?

 

[hallenhe]

This is facinating, but i do have a question, how sure are you that they lick vines for chemical ques, i always though that it meant they were thirsty, so everytime they licked a vine or whatever i would spry their cage and nearly everytime they would start drinking. You think it is just a coinsedence?

They do commonly drink from water droplets on leaves, vines, etc., and when I see my guy licking repeatedly when he has been recently misted, I don't hesitate to attribute that to thirst. The "licking for chemical cues" is a distinct behavior. At least in the case of my panther, it occurs as he's on the move, and generally in dry areas (his watering place is just a small portion of his "territory"). He will be walking along, will slow down, lean the head forward, extend the tongue just the slightest bit and touch it very gently to the surface, then resume his walk. I have observed this: on the curtain rod, on various ZooMed bendy vines, on the couch, the living room carpet, my arm, my husband's arm, the face of my husband's watch, the front sidewalk... Just one touch, not a lapping as with drinking. A certain spot on the curtain rod is "tasted" more often then not as he crosses it, and this same spot is often face-rubbed.