Iguana macro scales

Iguana scales create a complex dermal structure with keels and osteoderms that provide protection and camouflage.

About this subject

Iguana scales are far more than simple coverings. They are specialized dermal structures composed mainly of keratin, the same protein found in human nails. In green iguanas (Iguana iguana), each scale bears a raised central keel, forming ridges along the back and tail, a trait that names the family Iguanidae (from Taino iwana, meaning lizard). These keels help channel rainwater away from the body and provide additional rigidity.

Internally, many iguana scales contain osteoderms, small bony plates that develop in the dermis. These osteoderms are more common in terrestrial lizards like tegus, but also occur in iguanas, offering extra protection against predators. Scale color can shift rapidly thanks to specialized cells called chromatophores, allowing the iguana to adjust its coloration for thermoregulation and social signaling.

Remarkably, the arrangement of scales forms unique patterns in each individual, akin to fingerprints. Biologists use these patterns for identification in population studies. Scales are also sensory: beneath each are nerve endings that detect vibrations and touch, helping the animal perceive its environment. During shedding, iguanas replace scales in large patches, a process regulated by thyroid hormones.

Frequently Asked Questions

Why do iguana scales have keels?

Keels are raised ridges that channel rainwater away from the body, prevent dirt buildup, and add rigidity to the skin. They also aid camouflage by breaking up the animal's outline.

Do iguana scales contain bone?

Yes, in many iguanas scales contain osteoderms, small bony plates in the dermis that provide extra protection. This reinforcement is more common in terrestrial species.

How do iguanas shed their scales?

They shed scales in large patches, a process called ecdysis. The shedding is regulated by thyroid hormones and occurs periodically throughout life, allowing growth and skin renewal.