Here we are in a biodiversity paradise: the island of Madagascar. Many species of animals and plants live only here, it is impossible to observe them anywhere else in the world except on this piece of land bordering the Indian Ocean. They are said to be endemic to the island of Madagascar. So life here has evolved in a void cut off from the rest of the world. And it evolved in an unexpected, spectacular way, offering an explosion of shapes and colors like no other. Color is what we’ll be interested in today. Because the animal we want to observe is one of the few animals that has the extraordinary ability to transform on command. From the capital Antananarivo, we follow the road that heads north, in search of a jewel: Madagascar’s primeval forest. Primary forest is an extraordinary place. Protected from all activity, these original forests are a refuge for countless species that can live there away from the noise and polluting activities of humans. For example, the world’s ugliest orchid was discovered in this forest, Gastrodia agnisellus, whose flower resembles an open, sticky mouth. or, species brookesia nana, a tiny chameleon barely 1 cm tall, the smallest in the world! Because, in Madagascar, about half of the species of chameleons known on earth live. And today we have an appointment with one of them.
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Meet Madagascar’s giant chameleon
Here we are: on his tree, in the humidity of the tropical climate, a figure resembling a miniature dinosaur. A large lizard is sunbathing, it is a species of chameleon Auslett’s Fury, the giant chameleon of Madagascar! This emblematic species can grow up to 70 cm in length! Its color varies from brown to green, speckled with white or yellow, and it has a crest with small jagged spikes all over its body. Pay attention to its claws. Like us, this chameleon also has five fingers, but they are arranged a little differently than us. While our thumb opposes the rest of the fingers to form a claw – let’s just say it’s opposable, our friend has two fingers on one side and three on the other to grasp the branches. It’s a bit like holding a water bottle with your thumb and forefinger on the same side! It may seem impractical to you, but it is natural for chameleons. Ah… a carefree butterfly is coming. He takes a big risk, because chameleons love insects and may even swallow birds or small rodents. Be careful, little butterfly… The chameleon, with its prominent, independent eyes that roll into their sockets, is on the hunt for prey. Nothing survives that. In an instant, the chameleon’s tongue, as if mounted on springs, bursts out at full speed and melts onto the butterfly. It cannot escape the attack, as its tongue is of extraordinary length and its sticky end allows it to swallow its prey. The little butterfly has already reached the depths of the lizard’s belly. It may not move very fast on its branch, but it is unbeatable when it comes to hunting.
Chameleons are fascinating animals in many ways. But one of their abilities has made them famous: they are able to change color. For a long time, it was believed that this superpower allowed them to blend into any environment while going incognito. In short, it was used for camouflage. But researchers have discovered that the reality is a bit more complicated than that. To learn the secrets of a chameleon’s color, visit Arizona in the United States. You’ll notice that our extraordinary lizard has more than one trick up his sleeve…
Fighting and Emotions: The Hidden Side of Chameleons’ Color Changing
To better understand how and why chameleons change color, scientists at the University of Arizona held a large boxing tournament among chameleons. Because chameleons are very territorial, meeting fellow chameleons can quickly turn into a fight. For the purposes of the experiment, the researchers tested the reactions of 10 wild chameleons during an encounter with another individual. In this case, a helmeted chameleon was chosen for the experiment.
Originally from the mountains of Arabia, these chameleons have been brought to the United States and, more precisely, to the nearby state of Florida, which is very practical! They are named for the hanging tuft on their heads, although this feature is found in many chameleons. When two helmeted chameleons meet, a strange choreography ensues. Each puffs up his body, his belly, his tail, in order to appear momentarily more impressive in the eyes of his opponent. Then… a waltz of colors ensues. Each part of the chameleon’s body changes colour, from green to red, yellow, blue. The purpose of the ranged threat is to curb the fierceness of the opponent.
But how does a chameleon change colour? To understand this, we have to travel to the infinitely small, the heart of the chameleon’s skin. Because the cells of her skin are equipped with a secret weapon: they contain nanocrystals, ie crystals, like salt for example, so small that they are invisible to the naked eye! Depending on the biological state of the animal, these crystals move closer or move away from each other. And then they reflect light differently! Thus, when the chameleon rests, the microscopic crystals in its skin harden, reflecting the blue color that mixes with the naturally occurring yellow pigment in the chameleon’s skin. As a result, our little lizard has a beautiful green color. But, when the chameleon is aroused, things get complicated…
Chameleon’s body colors reveal its health and intentions
The helmeted chameleons participating in the experiment were placed in a large transparent box, face to face, on a branch. Then, to allow the chameleons to face each other, the window separating them is removed. During this experiment, the researchers studied at least 28 body regions of the chameleon. Thanks to the cameras, they do not miss a single fraction of the fighters’ behavior during the tournament. And what they discovered exceeded their expectations. As the researchers hypothesized, when two chameleons meet, they employ an intimidation strategy that involves changes in their bodies. As seen, they swell and the chameleon’s skin changes color from dark green to red, yellow or blue. But to his surprise, he discovered that these color changes actually had a purpose!
Based on the intensity and speed of color changes on different areas of a chameleon’s body, researchers have found that they can predict the outcome of a fight! For example, the more vivid and rapidly changing colors of the stripes on a chameleon’s flanks, the more likely it is to approach an opponent to fight it. But even more impressive. The colors of a chameleon’s head predict who will be the winner of a fight. Yes, yes ! Thus, while the chameleon’s stripes allow him to express his motivation, his head provides information about his fighting ability. All this thanks to measuring the speed of change of colors and their intensity. That’s a very useful power for a chameleon! Because when it’s time to fight, chameleons turn slightly to the side, exposing their stripes to their opponents’ eyes, as a way of saying, “I’m ready to fight,” or vice versa. “I am a supporter” of “peace”. When the fight is confirmed, the two chameleons come to each other to engage in what is called a head fight. informs about the abilities of the one he will have to fight against. Convenient isn’t it?
Therefore, contrary to popular belief, chameleons do not change color to blend in smoothly with any colored background, but to communicate their emotions, such as motivation to fight, or to express their abilities. . but that’s not all ! Chameleons are ectothermic, meaning they draw heat from their surroundings to keep their bodies at the right temperature throughout the year. Hence these survival aces are also able to change color to adapt to the variation of weather and always remain around 20°C. practical ! Researchers do not yet know how chameleons are able to express their ability to fight by changing the color of their head. This may be because healthy individuals produce more vibrant colors through more efficient biological reactions. But we still have a lot of work to do to unlock the secrets of chameleons’ incredible powers.