Whenever I scuba dive, my favorite species to observe always includes the jellyfish. Scyphozans (the “true jellyfish”) are exclusively marine. Jellyfish have roamed the seas for between 500 million and possibly 700 million years which makes them the oldest multi-organ animal.
With no vertebrae, or any boney structure, they are truly able to undulate in any direction supported by ocean water. Their ability to ‘dance’ surpasses about any other living animal.
photo credit: Oday Hazeem