Chameleon

Chameleons, or chamaeleons, are a special group of lizards known for changing colors. This helps them hide in their surroundings. They belong to a family called Chamaeleonidae and there are about 200 different kinds of them.

These lizards have many unique features. They have special feet that help them climb, tails they can grab with, and flat bodies. Some have crests or horns on their heads. Their eyes can move separately, which helps them see clearly when catching food.

Chameleons are mostly active during the day and eat insects, though the bigger ones can also catch small animals. Most live in trees, using their tails for balance, but some live on the ground. They are found in many places, mostly in Africa, with many species living only on the island of Madagascar. There are also a few in southern Europe, Asia as far as India and Sri Lanka, and some have been introduced to places like Hawaii and Florida.

Etymology

The word "chameleon" comes from old languages. It began with the Greek word khamailéōn, meaning "lion of the ground." This Greek word was then used in Latin as chamaeleōn. The English word "chameleon" came from this Latin word.

Classification

Chameleons belong to a family called Chamaeleonidae. In 1986, scientists split this family into two groups: Brookesiinae and Chamaeleoninae.

Brookesiinae included small chameleons like Brookesia and Palleon. Chamaeleoninae included larger ones such as Bradypodion and Chamaeleo.

Since then, scientists have talked about these groups. By 2015, a researcher named Glaw updated the classification. He put only Brookesia and Palleon in Brookesiinae. He placed all other chameleons in Chamaeleoninae.

Change of colour

Further information: Animal coloration and Signaling theory

Some chameleons can change their skin colors. They can show many different colors such as pink, blue, red, orange, green, black, brown, yellow, and purple. This happens because their skin has special cells that change how light looks on them.

Chameleons use color changes to talk to each other and to keep their body at the right temperature. They may show bright colors when they feel strong or darker colors when they are calm. Some chameleons can change colors to hide better from animals that might hurt them.

Evolution

The oldest known chameleon is Anqingosaurus brevicephalus from the Middle Paleocene of China. Other old chameleon fossils have been found in the Czech Republic, Germany, and Kenya.

Scientists think chameleons may have lived much longer ago than these fossils show. They might have shared a common ancestor with iguanids and agamids over 100 million years ago. Though many chameleons live in Madagascar today, they likely started in mainland Africa, with some early moves to the island.

Studies show that the way chameleons change color has changed based on where they live. Chameleons in bright areas tend to show bright colors, while those in dark areas show colors that stand out more. This helps them talk to other chameleons.

Description

Chameleons are amazing lizards that come in many sizes and shapes. The smallest chameleon, Brookesia nana, is less than an inch long. The largest, like Furcifer oustaleti, can be over two feet long. Many chameleons have special features on their heads, such as horns or crests. Males often look different from females.

Chameleons have special feet that help them climb trees. Their feet have five toes split into two groups, so they can grip branches tightly. They also have sharp claws for climbing. Some chameleons have spikes on their backs to help them hide.

Chameleons can see very well and can even see ultraviolet light. Their eyes move on their own, giving them great vision in all directions. They catch insects by shooting out their long tongues quickly to grab prey from far away. Some chameleons from Madagascar have bones that glow under ultraviolet light, which may help them talk to each other.

Distribution and habitat

Chameleons mostly live in sub-Saharan Africa and on the island of Madagascar. Some kinds are also in northern Africa, southern Europe like Portugal, Spain, Italy, Greece, Cyprus, and Malta, the Middle East, southeast Pakistan, India, Sri Lanka, and islands in the western Indian Ocean. There are also chameleons in Hawaii and Florida that were brought there by people.

These lizards like warm places such as forests, woodlands, shrublands, savannas, and sometimes deserts. Most chameleons live in trees or bushes, but some walk on the ground. Many chameleon kinds live only in small areas and can be hurt when their homes are destroyed.

Reproduction

Most chameleons lay eggs, but some give birth to live babies. The mother digs a hole to put the eggs in. Small chameleons may lay just a few eggs, while larger ones can lay many. It can take several months for the eggs to hatch.

Some chameleons, like the Jackson's chameleon, give birth to live young after carrying them for about six months. Each baby chameleon is born inside a thin, clear sac and climbs away to start its own life soon after.

Diet

Chameleons mainly eat insects. Larger ones might also eat small lizards or birds. The veiled chameleon from Arabia eats crickets and leaves when there is little water. Jackson's chameleon from Kenya and northern Tanzania eats small animals like ants and caterpillars, and also plants like kale and berries. The common chameleon found in Europe, North Africa, and the Near East mostly eats wasps and mantises. It should eat a mix of waxworms, earthworms, and green leaves. Some chameleons, like the panther chameleon from Madagascar, get vitamin D3 by sitting in the sunlight. This helps them make more of this important vitamin.

Anti-predator adaptations

Chameleons have many natural enemies, including birds, snakes, and even tiny creatures like ants that threaten their eggs and young. Because they can't usually run away, chameleons hide instead.

They change their colors and patterns to blend into their surroundings or to break up their shape, making it hard for predators to see them.

If a chameleon is spotted, it will stand its ground. It might flatten its body to look bigger, open its mouth to warn an attacker, and if needed, use its feet and jaws to defend itself. Sometimes, it will also make noises to show it means business.

Parasites

Chameleons can get sick from tiny creatures called parasites. One type is called nematodes, or roundworms. These can spread by insects like ticks and mosquitoes. Another way these parasites get into chameleons is through food that has roundworm eggs.

Chameleons can also be affected by other parasites, such as protozoa. They may also get parasites called coccidia.

As pets

Chameleons are popular pets. People often bring them in from countries like Madagascar, Tanzania, and Togo. Common types include the Senegal chameleon, the veiled chameleon, the panther chameleon, and Jackson's chameleon. These animals need special care.

The United States has imported many chameleons since the 1980s. Rules have changed to protect wild chameleons. Some chameleons have become invasive in places like Florida. Still, chameleons remain popular pets. Many are now bred in the U.S. for sale.

Historical understandings

Ancient thinkers like Aristotle wrote about chameleons in his book History of Animals. Later, Pliny the Elder also talked about them in his Natural History. He wrote about their ability to change colors to hide.

The chameleon appeared in books like Conrad Gessner's Historia animalium in 1563. It was even mentioned in Shakespeare's Hamlet, where a character made a joke about chameleons. This shows what people believed back then.