Iguanidae

Iguanas are many kinds of lizards.

Some are big and some are small. Most live in warm lands.

They like to sit in the sun. This helps them stay warm.

Many iguanas live in trees. Some others like the ground. They mostly eat plants.

They have sharp claws to help them move. They also have long tails.

Some iguanas live on islands. They can be pink or blue. These lizards are very special. They are amazing animals to see.

Iguanas are a big family of lizards.

This group includes green iguanas and chuckwallas. They live in warm places. Most live in South America or the Caribbean.

Some live in the Pacific islands too.

Most iguanas have a few special parts. They have spines on their backs. They have a dewlap, which is a flap of skin on the neck. They also have sharp claws and long tails. Many live in trees. Others like to stay on the ground. Most iguanas are herbivores. This means they eat plants.

These lizards are poikilothermic. This means they cannot make their own body heat. They must sit in the sun to stay warm. They lay eggs and do not care for them much. But they do guard their nests.

Some iguanas live on only one island. The blue iguana lives on Grand Cayman. The pink iguana lives on the Galapagos islands.

Other kinds, like the Fiji iguana, traveled a long way. They may have floated across the ocean on plants.

The Iguanidae is a large family of lizards. This group includes the well-known green iguana and the chuckwalla. These animals are very important to study because they are so diverse. They come in many different sizes and shapes. Some live in trees, while others prefer the ground. They mostly live in warm, tropical places.

Many iguanas share similar physical features. They often have spines along their backs. Most have a dewlap, which is a flap of skin on the neck. They also have sharp claws and long, whip-like tails. Most of these lizards are herbivores. This means they eat plants found in their habitat. They are also poikilothermic. This term means they cannot make their own body heat. They must bask in the sun to stay warm.

Scientists have studied how this family changed over millions of years. The Iguaninae group likely began about 62 million years ago. This was during the early Paleocene period. One group, called Dipsosaurus, split away about 38 million years ago. Later, the Brachylophus genus appeared about 35 million years ago. This happened after they moved to the Pacific. Other modern groups formed during the Neogene period.

These lizards live in many different locations. Most are native to the Americas. They range from the United States to Argentina. Some species live only in one small place. The Galapagos pink iguana lives only on the Galapagos islands. The Grand Cayman blue iguana lives in a small reserve.

Other iguanas, like the green iguana, have spread to places like Japan and Hawaiʻi. This happened because of the pet trade.

Some iguanas have completed amazing journeys. The Brachylophus iguanas live on Fiji and Tonga. Scientists think they traveled a very long way. They may have rafted across the Pacific Ocean. This trip was over 8,000 kilometers long. This is the longest overwater trip ever recorded for a vertebrate. It shows how even small animals can find new homes.

The Iguanidae is a diverse family of lizards. This group includes iguanas, chuckwallas, and several prehistoric relatives. These animals are important to study because they show how life adapts to different environments. They vary greatly in size, appearance, and habitat. Most thrive in warm, tropical climates. You can find them in South America and islands across the Caribbean and Pacific.

Most members of this family share specific physical traits. They often have dorsal spines, which are pointed scales, running along their backs. Many possess a dewlap, a flap of skin hanging from the neck. They also feature sharp claws and long, whip-like tails. Most iguanas are herbivores, meaning they eat plants available in their area. Many species are arboreal, living in trees. However, some are terrestrial and prefer life on the ground.

Iguanas are poikilothermic reptiles. This means they cannot regulate their own body heat internally. Instead, they must rely on external sources to manage their temperature. They often engage in basking, which is sitting under the sun to stay warm. This process is essential for their survival. When they lay eggs, they are typically oviparious. While they provide little to no care for their young after hatching, some species do display nest-guarding behavior.

The evolutionary history of the Iguaninae subfamily is quite long. This group likely originated during the early Paleocene, about 62 million years ago. The genus Dipsosaurus is considered the most basal extant genus. It diverged from the rest of the Iguaninae during the late Eocene, roughly 38 million years ago. The genus Brachylophus followed a few million years later, around 35 million years ago. This likely occurred after a dispersal event to the Pacific. All other modern genera formed during the Neogene period.

Most modern iguanas are native to the Americas. Their range stretches from the Southwestern United States through Mexico and Central America. They extend through the Caribbean and South America down to northern Argentina. However, some species are endemic, meaning they live in only one specific place. For example, the Galapagos pink iguana is found only on the Galapagos islands. The Grand Cayman blue iguana is limited to a small wildlife reserve on Grand Cayman.

Some iguanas have traveled much further from their original homes. The genus Brachylophus is found on Fiji and Tonga. Scientists believe these lizards moved via the longest overwater dispersal event recorded for a vertebrate. They likely rafted over 8,000 kilometers across the Pacific Ocean from the Americas. Other species, like the green iguana, have spread to Japan and Hawaiʻi. This spread often happened because of the exotic pet trade or illegal introductions into new ecosystems.

Taxonomy, the science of naming and classifying organisms, has changed for this family. Historically, researchers used different groupings for various lizards. In 1989, scientists Frost and Etheridge formally recognized several groups as families. Later, in 1997, Macey and colleagues used molecular data to identify a monophyletic Iguanidae. This means all members share a single common ancestor. More recent studies in 2011, 2012, and 2013 have provided even more comprehensive phylogenies. These studies help scientists understand the exact relationships between different lizard groups.