If you've ever visited an aquarium or watched a David Attenborough show, you'll know that the ocean is filled with exotic and mystifying creatures that seem to be from another planet. As humans, it's much easier to relate to other land mammals and the various critters we observe in our daily lives. Ocean-dwellers are fascinating because they're so different to us. Some of them live in mucus bubbles, and others use pee as a form of communication. What's not to love!
Click through the following gallery to learn some of the most amazing facts about the most wonderful underwater creatures.