* Skin: The most common outer covering is skin, which protects animals from the environment, regulates temperature, and helps with sensory perception. Even animals like jellyfish have a layer of skin-like tissue.
* Scales: Fish, reptiles, and some insects have scales for protection.
* Feathers: Birds have feathers for insulation, flight, and display.
* Fur or Hair: Mammals have fur or hair for warmth, protection, and communication.
* Exoskeletons: Insects, crustaceans, and some other invertebrates have hard, external skeletons called exoskeletons.
So, while some animals have coverings that are less obvious than others, no animal group lacks an outer covering entirely.