Oyster

ocean · mollusc · filter feeder · shellfish

Two-shelled creatures. Oysters are bivalves, meaning they have two hard shells that open and close to protect their soft bodies inside. These shells can be bumpy, smooth, or wildly irregular shapes.

Ocean water filters. Oysters eat by filtering tiny food particles straight from the seawater around them, acting like nature's water purifiers. A single oyster can filter up to 50 gallons of water per day.

Shell-stickers. Most oysters cement themselves to rocks, docks, or other oysters and stay in one spot their whole lives, unlike many other sea creatures that roam around.

Pearl makers. When something irritating gets inside an oyster's shell, it coats it with a shiny substance called nacre to protect itself, sometimes creating beautiful pearls.

Salt water dwellers. Oysters live in salty ocean waters and brackish habitats (places where rivers mix with the ocean), never in fresh water.