The amazing feet of a gecko

Geckos can stick to surfaces because their bulbous toes are covered in hundreds of tiny microscopic hairs called setae. Each seta splits off into hundreds of even smaller bristles called spatulae. Scientists already knew that the tufts of tiny hairs get so close to the contours in walls and ceilings that the van der Waals force kicks in. This type of physical bond happens when electrons from the gecko hair molecules and electrons from the wall molecules interact with each other and create an electromagnetic attraction...

A gecko by definition is not sticky — he has to do something to make himself sticky," study lead author Alex Greaney, a professor of engineering at Oregon State University in Corvallis, told Live Science. "It's this incredible synergy of the flexibility, angle and extensibility of the hairs that makes it possible."

Greaney and a team of researchers created a mathematical model that shows how the setae angle and the forces that act on a gecko as it climbs interact to create a delicate but powerful sticking system.

Additional explanation at LiveScience.  Photo via.

The skin of some animals contains light-sensitive opsins

YouTube link.

By far the most interesting item I've read this week is at Not Exactly Rocket Science:

When Domenico Fulgione placed Moorish geckos on dark surfaces, he saw what he had seen for years. These spiny, hand-sized lizards changed colour. Within an hour, their typical creamy white complexions transformed into blacker hues that better matched their environment.

And then Fulgione blindfolded the geckos.

They still changed colour. How does an animal adjust its colour to match its environment, when it can’t see that environment at all?...

These bizarre results started to make more sense when the team analysed the gecko’s skin. They found that the skin is rife with opsins—light-sensitive proteins that are the basis of animal vision. When light enters your eyes, opsins in your retinas respond by triggering chemical reactions that send signals to your brain. That’s how you see. The Moorish gecko has plenty of opsins in its eyes too, but the team also found these proteins all over the skin of its torso. It’s especially common in the lizard’s flanks, and in cells called melanophores that are filled with dark pigments.

The researchers think that the flank opsins can respond to surrounding light levels and automatically adjust the gecko’s colour. If they’re right, the lizard has a kind of distributed vision that is independent of its eyes, and perhaps its brain. In other words, it can “see” with its skin.

Fascinating.  More details at Not Exactly Rocket Science.

I found the video of an octopus several months ago at 22 Words.

Uroplatus phantasticus - the Satanic Leaf-Tailed Gecko

This gecko from Madagascar has feet that "contain about a billion microscopic points that bind to individual molecules, allowing the animal to walk upside down on smooth surfaces." Photo credit to Piotr Naskrecki, from a book of macrophotography, "The Smaller Majority," which I hope to review here next week.

The generic name, Uroplatus, is a Latinization of two Greek words: "ourá" (οὐρά) meaning "tail" and "platys" (πλατύς) meaning "flat". Its specific name phantasticus is the Latin word for "imaginary" based upon the gecko's unique appearance..

The photo enlarges nicely with a click.

Reposted from 2009 to add another photo (via):

Camouflage

Geckos are amazing creatures. I've previously blogged the Satanic Leaf-Tailed Gecko. Here is the Mossy Leaf-Tailed Gecko resting on a sapling in Madagascar, and demonstrating world-class camouflage:

As it awakens it raises its head, revealing the fringe along the sides of its body which blurs the line between itself and the substrate.

And having seen that, did you even notice the digits of its forelimb? Click to enlarge the picture.

Photo credit Gregory G. and Mary Beth Dimijian; photo collage created from three individual photos posted at their website.

Perfect camouflage

This is a lined leaf-tailed gecko (Uroplatus lineatus) from Madagascar.  It looks for all the world like a model of a gecko carved from wood.  That's the camouflage it has evolved to survive in a bamboo forest.  Very cool.

Photo credit: David d'O, via Electric Orchids.

Gecko

A photograph of his pet gecko by Shikhei Goh,via The Telegraph.  You can view many more of his photos at 500px.

Credit: Shikhei Goh/ Barcroft USA

Ants eating a dead gecko

If you're going to waste your time surfing the net, you might as well waste it watching ants eating a gecko. And since it's time-lapse photography, you will waste much less time than you would watching the same thing in real life. That's what the internet is for.

Eye of Smith's Green-Eyed Gecko

An interesting adaptation of the musculature of the iris, constricting to leave three small orifices.
Credit

Psychedelic

Found at snuh, but I can't locate a primary source - or even whether this is a real lizard, or a CG-enhanced one.

A hat-tip to Julie for (quickly!) identifying this as a Tokay gecko.  With that lead I found several pix at Flickr, but  haven't located the photographer to credit this particular one.

What a remarkable creature!

Gecko shedding

Via.

Fake amber

When you see a gecko embedded in "amber" for sale on eBay for 10 bucks, you have to figure the "amber" is fake (hornets, scorpions, butterfly specimens similarly priced at the link).  The item's description says "Manufacture: China, Chinese Factory Homegrown products for Sales", so that's probably a "disclosure," and the "amber" in the title can be defended as a color rather than a natural product.

This one is crudely done, but there are some remarkably good ones out there, as explained at Amber Pieces:

This industry dates back to the early 1900s, having its major source in New Zealand, where large amounts of Kaori Gum are located - the prime ingredient in the fabrication of fake amber. In the North Island, diggings of Kaori Gum would be performed daily, turning it into a major industry. It may be hard to imagine, but even the workers were so engaged in their activities that they formed their own newspaper called “The Gum Diggers Gazette”. If you wonder how this Kaori Gum was used as a surrogate for real amber, here is how it was done: the material would be melted down gently and carefully. Inclusions would then be placed into it, e.g. suitably colored insects which can easily be detected as fake fossils because true ancient amber fossils are colorless and monotone due to time usage..modern imitations are so close to perfection that simple analytical methods fail to differentiate between real amber and fake amber. Scientists developed the so-called FT-IR Spectroscopy test for the infallible identification of Baltic amber – succinite. Under close examination, real amber reveals its Baltic curve in spectrum coupled with gas chromatography and electron microscopic features... 

Baltic Essentials offers tips on how to spot fake amber:

You can easily rub amber with your hands or with a cloth to produce heat as well to see if it emits a tree resin smell.  There will also be an oily residue that appears on your hands after several seconds of rubbing very fast.

Real amber also has an electrostatic charge, and when rubbed it will attract to things like your clothes, hair, or dust.

In salt water, genuine amber will float while most fakes, which are denser in weight, will sink.

Authentic amber is florescent and shining UV light over it will glow pale

Related:  Jurassic amber soap, Be aware of fake tanzanite, Fake gold bars (and coins) made of tungsten, Floating crinoid fossil - fake or real?

Photos from Moqo-Moqo

I can't conceive of what biological necessity or selection pressures would cause a line of skinks to develop blue tongues. Fascinating.

Credit for skink, blue Harlequin shrimp, the blue-spotted Leopard moth, and the molting ?gecko.

"The Smaller Majority"

Several weeks ago I blogged a startling photograph of the Satanic Leaf-tailed Gecko. Curious about the photographer and his work, I requested the book from our library. The Smaller Majority is a 300-page "coffee table" photo book detailing Piotr Naskrecki's life work of capturing images of the small creatures of savannas, deserts, and tropical forests. Unlike many similar books, this one has not only gorgeous images but also intelligent and interesting text.

Examples of "TYWK"-type information include these two tidbits -
1) Butterflies that "puddle" at muddy spots or collections of animal dung are seeking sodium, which is rarely found in plants (potassium is the principal cation in vegetation). "In extreme cases a moth may imbibe an amount of fluid 600 times its own weight in a single puddling session, expelling the excess water as it drinks and retaining only the precious [sodium]."
2) Ant lions (larvae of owl flies) catch and consume insects, but they "are missing two elements of the body that seem to be absolutely critical for any predator: the mouth and the anus."

The lower photo above is a pupa of an "unidentified Yponomentidae." The mesh-like cocoon that enfolds it is just awesome. There are lots of other pix like this in the book - mostly frogs, cockroaches, ants, spiders, mantids, katydids - things like that. You can see a small sample at his Flickr photostream.

Sclerotic rings

I had never heard of these until today.

Sclerotic rings are rings of bone found in the eyes of several groups of vertebrate animals, except for mammals and crocodilians. They can be made up of single bones or small bones together. They are believed to have a role in supporting the eye, especially in animals whose eyes are not spherical, or which live underwater. Fossil sclerotic rings are known for a variety of extinct animals, including ichthyosaurs, pterosaurs, and dinosaurs, but are often not preserved.

A third image at Wikipedia illustrates that these rings were actually inside the eye, not just around the eye.   The top skull is from a leaf-tailed gecko, and the lower skeleton is of the appropriately named opthalmosaurus.

You learn something every day.

Via Scientific Illustration.

Psychedelic eyes

Giant leaf-tailed gecko of Madagascar, photographed by Quinton Robinson, via Neatorama.