Chameleons: The true magicians of the African bush
Chameleons are a distinctive and highly specialized clade of old world lizards with around 202 different species occurring around the world. Currently, there are 19 species formally described in South Africa, around 80% of these are endemic to South Africa. There are 17 species of dwarf chameleons and 2 species of typical chameleons.
The species of chameleon we find and have around Jabulani lodge and on Kapama are Flap Neck Chameleons (Chameleo dilepis) the largest chameleon in Southern Africa and the most common.
Now chameleons are really cool little animals, from their eyes to their tails and all the way to their skin which is where the real “magic” happens. Chameleons are truly apex predators of the reptile world in more ways than one.
- The eyes: Chameleons have a distinctive visual system that enables them to see their environment in almost 360 degrees (180 degrees horizontally and +/-90 degrees vertically). They do this in two ways. The first is with anatomical specializations that enable the eyes to rotate with a high degree of freedom. The second is the chameleon’s ability to transition between monocular and binocular vision, meaning they can view objects with either eye independently, or with both eyes together.
- The tongue: Chameleon tongues are extremely fast and long. They can be anywhere from one to 11/2 times the body length of the owner and can rocket in and out with blinding speed. A 51/2″ tongue reaches full extension in 1/16th of a second, which is fast enough to snatch a fly in midair. The tongue consists of three primary components: The sticky tip, the retractor muscles and the accelerator muscles. (musculus accelerator linguae). When at rest, the whole assembly sits at the bottom of the mouth, the base placed down in the throat behind the head. Before striking, the lizard moves it toward the front of the mouth and muscles raise the hyoid bone above the lower jaw. After aiming with the entire head, the chameleon is ready to fire. The tip of the tongue resembles a club. Covered with sticky saliva, it’s abrasive surface also grips, High-speed photographs of the tongue in flight reveal a flap of skin trailing the head of the club. The flaps wrap partially around the prey on impact. Wet worms or slugs, however, frustrate the system because the saliva won’t adhere to their slimy surface. The tongue can pull in about half of the chameleon’s body weight. Because speed is less important for reeling in prey than catching it, the retractors don’t exhibit the speed of the accelerator muscles. Most of the time the tongue collapses and recoils on the way back, like a strand of spaghetti being sucked in.
- The skin: The skin of the chameleon has to be the coolest aspect about them, giving them the ability to change colour at will. Not all chameleons can change their skin colour completely, many chameleon species are able to vary their colouration and pattern through combinations of pink, blue, red, orange, green, black, brown, light blue, yellow, turquoise, and purple. The way they achieve this is through a superficial layer which contains pigments, and under the layer are cells with guanine crystals. Chameleons change colour by changing the space between the guanine crystals, which changes the wavelength of light reflected off the crystals which changes the colour of the skin.For a long time, it was thought that chameleons change colour by dispersion of pigment-containing organelles within their skin. However, research conducted in 2014 on panther chameleons has shown that pigment movement only represents part of the mechanism.
Chameleons have two superimposed layers within their skin that control their colour and thermoregulation. The top layer contains a lattice of guanine nanocrystals, and by exciting this lattice the spacing between the nanocrystals can be manipulated, which in turn affects which wavelengths of light are reflected and which are absorbed. Exciting the lattice increases the distance between the nanocrystals, and the skin reflects longer wavelengths of light. Thus, in a relaxed state the crystals reflect blue and green, but in an excited state the longer wavelengths such as yellow, orange, green, and red are reflected.
The skin of a chameleon also contains some yellow pigments, which combined with the blue reflected by a relaxed crystal lattice results in the characteristic green colour which is common of many chameleons in their relaxed state.
Which is why when we typically find chameleons in the bush they will be a light to dark colouration of green.
Now when it comes to chameleons many have believed that colouration change was due to camouflage, allowing them to blend in to an environment to evade predators but that has also proven to be a different story, chameleons actually use the ability to display moods and feelings, particularly when it comes to stress, anger, excitement and also thermoregulation.
These are but merely a small amount of fun interesting facts about chameleons, hopefully enough to keep you interested to learn more about these fascinating creatures.