Hobbies And Interests
Oxygen
Crustaceans have gills instead of lungs. The gills need to be kept moist for the oxygen molecules to dissolve into the moisture, once this has happened the molecules enter the body of the crustacean and its circulatory system. Waterborne crustaceans absorb oxygen in this manner, and those that live on land keep their gills damp using fluids from inside their bodies.
Food
The way food is transported largely depends on the type of crustacean. "Maxilipeds," such as those with many legs, such as crabs and shrimp, use the first three pairs of legs to grasp food. Smaller crustaceans such as krill, have appendages on their body that can generate small water currents, bringing food within their reach.
Considerations
Crustaceans are an essential part of the food chain. Plankton is eaten by krill, which is eaten by larger fish and so forth. Each species has a unique way of transporting food and eating to enable them to survive and provide food for other crustaceans.