Many animals have keratin. Keratin is a fibrous structural protein that is a key structural material making up the outer layer of human skin. It is also the key structural component of hair and nails. However, certain types of keratin are primarily found in specific animal groups.
Types of Keratin
There are different types of keratin. One significant distinction is between alpha-keratins (α-keratins) and beta-keratins (β-keratins).
- Alpha-keratins: Found in mammals (including humans) and are the primary protein in hair, nails, and the outer layer of skin.
- Beta-keratins: According to the provided reference, are found exclusively in sauropsids, encompassing all living reptiles and birds.
Animals with Beta-Keratin
The harder beta-keratins (β-keratins) are unique to reptiles and birds. Here’s a breakdown of where beta-keratin is found in these animals:
- Reptiles:
- Nails
- Scales
- Claws
- Shells (in some reptiles like tortoises, turtles, and terrapins)
- Birds:
- Feathers
- Beaks
- Claws
Therefore, while many animals possess keratin, beta-keratin is specifically found in reptiles and birds, making up structures like scales, feathers, beaks, and claws.
