The upper skin layer, called the dermis, of the typical amphibian often includes mucous and poison glands. The mocous glands help provide essential moisture to the body. These glands produce poisons that are toxic to natural enemies, such as birds and small mammals, but that rarely harm humans. These glandular secretions give some amphibians distinct odors. The spotted salamander and the commom toad smell of vanilla.
Some frogs smell onion, and the fire-bellied toad smells of garlic.
The skin's protective properties include the ability to change color so that the animal can hide when an enemy is nearby. Certain cells under the skin alter the color so that the amphibian can blend into its surroundings. Sometimes parts of the skin become brightly colored. The amphibian displays these colors to enemies to warn them to keep away. The sense organs very greatly, depending on the order and the species.