What's up with the color color colors of Chameeeleons, they come and go.
They come and go!
Changing color is a rarity in the animal world, and also a mystery, until now!
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Chameleons change color so well, and are so well known across the planet for doing so,
that their name is synonymous with someone who is good at changing their look, behavior
or opinions as their situation changes.
Most people think chameleons change color for camouflage, but that's not it at all!
Only the males can change color, and they do so to communicate danger to other nearby
chameleons, or for a mating display.
Ladies.
*wink*
It's a pretty dramatic show when a chameleon swaps its green for bright red, and thanks
to new research, we now know HOW they do it.
Researchers from the University of Geneva looked at the skin cells of chameleons to
observe how they change color.
Within their skin, it turns out, chameleons have cells called iridophores.
Suspended within those cells are tiny guanine nanocrystals which are formed into a lattice.
When relaxed, the chameleons’ iridophore lattices are contracted, and mainly reflect
blue light, but when excited the chameleon expands and three dimensional lattices expand
along with them, reflecting different wavelengths of light!
Below that layer, there's a layer of skin with even larger nanocrystals which reflect
near-infrared light; providing "passive thermal protection."
Which is great, because these cold-blooded animals can't change their body temperature;
changing that base layer may be one way they can affect how much near-infrared light, and
therefore heat, is absorbed into their body,.
Camouflage is also called cryptic coloration; or a color and pattern that makes an animal
difficult to discern from its surroundings; concealing it.
The ability to CHANGE colors isn't unique to chameleons -- some fish, frogs, insects,
crustaceans, cephalopods, and other lizards can do it too, but they don't have nanocrystals…
this research is the first time that's been seen in reptiles.
And other animals use different methods of color shifting.
Cuttlefish, for example, can also change their colors at will; but rather than crystal-filled
iridophores, they use chromatophores.
Chromatophores are sacs of a single pigment of color surrounded by muscle.
The cuttlefish has learned to widen or constrict that sac to show more or less of that color.
Invertebrates like cephalopods use these chromatophores too, and for more on that you can check out
our video exploring how the disco clam can reflect light like a disco ball!
Over time, evolution, mutation and simply breeding with others can cause changes in
the colors of species, humans included -- all blue-eyed humans descend from a single mutated
ancestor.
Usually because those animals which have these colorful adaptations tend to survive better.
Zebra stripes confuse predatory eyes, helping to disguise individuals and making the herd
look more massive; background matching camouflage helps both predators like tigers blend with
their environment; as well as helping their prey hide by resembling it's surroundings…
but these adaptations take many generations to develop!
Active color change is pretty rare in the Animal Kingdom.
Before this research, scientists believed chameleons changed color the same as cuttlefish
or octopuses, but once they put the skin cells into a super-magnifying electron microscope,
they were able to see this unique and super cool system for reflecting light!
How do you think humans camouflage into our surroundings?
Do we?
Why or why not...