The body of an animal is protected by a covering: fur (hair) on the cat, feathers on the blackbird, scales on the fish, a shell on the snail, and smooth wet skin on the frog.
Examples
Example 2.7 (Who wears what)
Stroke a cat: fur. Pick up a fallen blackbird feather: light and soft. Look closely at a fish at the market: rows of shiny scales, like tiny roof tiles. Three animals, three different coats.