Scientists really don’t know yet how feathers evolved. Some scientists believe feathers probably began as modified scales. These changed scales were not intended for flight, but rather for insulation to preserve the reptile’s body heat. Eventually, they evolved into feathers. Other scientists believe feathers evolved from scutes similar to the thick scales on the top of a bird’s foot. Analysis shows that the bird scutes, scuttelae, claw sheathes, beak sheathes, and scales around a bird’s eyes have the same chemical composition as feathers, and they are controlled by the same genes. Crocodiles, a sister group of the dinosaurs, also have scutes, with a similar (but not identical) chemical composition to bird scutes. Scientists also know that dinosaurs had scutes, too, but they don’t know the composition. Of course, to confuse matters even more, some scientists speculate that scutes evolved from feathers.