Animals are always concealing themselves in order to survive. Sometimes they don’t even try. It’s just automatic.
An Emerald Tree Boa. (Sorry for the poor focus.)
A baby Loon.
A deer in the woods.
Others change their appearance to look like their surroundings. I saw (barely) this frog on our porch spigot. It’s amazing how he is the exact color of the metal.
And others use their surroundings to conceal them.