In Birds and Reptiles
The epidermis of birds and reptiles is closer to that of mammals, with a layer of dead keratin-filled cells at the surface, to help reduce water loss. A similar pattern is also seen in some of the more terrestrial amphibians, such as toads. However, in all of these animals there is no clear differentiation of the epidermis into distinct layers, as occurs in humans, with the change in cell type being relatively gradual. The mammalian epidermis always possesses at least a stratum germinativum and stratum corneum, but the other intermediate layers found in humans are not always distinguishable. Hair is a distinctive feature of mammalian skin, while feathers are (at least among living species) similarly unique to birds.
Birds and reptiles have relatively few skin glands, although there may be a few structures for specific purposes, such as pheromone-secreting cells in some reptiles, or the uropygial gland of most birds.
Read more about this topic: Skin
Famous quotes containing the words reptiles and/or birds:
“The man who never alters his opinion is like standing water, and breeds reptiles of the mind.”
—William Blake (17571827)
“man also knoweth not his time: as the fishes that are taken in an
evil net, and as the birds that are caught in the snare; so are the
sons of men snared in an evil time,”
—Bible: Hebrew Ecclesiastes (l. IX, 12)