"seal"的定义和意义

What is a "seal"?

Seals are aquatic mammals that belong to the family Phocidae. They are characterized by their streamlined bodies, short, stiff fur, and flippers that are specially adapted for swimming in water. Seals are found in both polar and temperate waters and are divided into two groups: the true seals (also called earless seals) and the eared seals (also called sea lions and fur seals). True seals are distinguished by their lack of external ears and their ability to move on land by wriggling along on their bellies. Eared seals, on the other hand, have external ears and are able to walk on all fours using their flippers like legs. Seals are important predators in the marine food chain, feeding on fish, squid, and other marine animals, and they are also hunted by larger predators such as sharks and killer whales.