Spiny-crested lizards are a group of lizards that are characterized by their spiny crests. They are closely related to iguanas, which are a large group of lizards native to Central and South America. The most common species of spiny-crested lizards are the green iguana, the desert iguana, and the chuckwalla. These lizards are known for their ability to climb and swim, and they are often kept as pets.