All the way up the food chain, stopping at us humans, is the desire to eat and try not to get eaten, and one of the best ways not to get eaten is to ‘hide in broad daylight’ as the saying goes.
There are several creatures who are very good at it – tigers for instance have stripes that blend in with their surroundings, making it difficult for an unsuspecting antelope to see them creeping through the grass. On a smaller scale, many different insects are really cleverly disguised to mimic leaves or flowers, such as the Dead Leaf Grasshopper, or the Orchid Praying Mantis. Even fish do it, such as the Stonefish or Flounder, and birds like the Great Grey Owl, who will blend with a tree so effectively a mouse would probably run over it before realising it was there.
Chameleons I always thought were pretty good at disguising themselves to hide from predators, by magically changing colour, but it turns out I am entirely wrong. They were my favourite masters of disguise, and they do change colour, but it isn’t a disguise for all of them. The chameleon’s uncanny ability to change colour has long mystified people, but now the lizard’s secret is out – they mostly change colour to regulate their temperatures or to signal their intentions to other chameleons, for example.
They are lizards that are part of the scientific family called Chamaeleonidae. In addition to the ability to change colour, chameleons have many other characteristics that make them special, including parrot-like feet, eyes that can look in two different directions at once and long tongues and tails. Many can run up to 20 miles an hour and can avoid predators quite easily, so camouflage is only a secondary reason for changing colour. They also are distinguished by their swaying gait, and the larger ones have a definite prehensile tail.
They can be found in Africa, Europe, Asia and North America. There are around 200 different species of chameleons according to Wikipedia, and they can live in both rainforests and deserts.
So why would they want to change colour?
Scientists believe they do this to reflect their moods. By doing so, they send social signals to other chameleons. For example, darker colours could mean a chameleon is angry. Lighter colours might be used to attract mates. Others change colours to help their bodies adjust to changes in temperature or light.
For example, a chameleon that gets cold might change to a darker colour to absorb more heat and warm its body.
So how do they pull off these colourful changes?
The outermost layer of the chameleon’s skin is transparent, and beneath this are several more layers of skin that contain specialized cells, tiny sacs of different kinds of pigment. The deepest layers are filled with brown melanin - the same pigment that gives human skin its many shades. The next layer are cells with a blue pigment that reflect blue and white light, and layered on top are ones that contain yellow and red pigments respectively. When a chameleon experiences changes in body temperature or mood, its nervous system tells specific cells to expand or contract, and this changes the colour of the cell, and it is capable of producing a dazzling array of reds, pinks, yellows, blues, greens, and browns.
These bold statements won’t necessarily help them blend into the background, but they will allow them to get their message across to other chameleons loud and clear!
So there you are, a creature that looks tough and leathery on the outside, but inside is a sensitive soul who wears, if not his heart, certainly his colours, on his sleeves!