海豹是对鳍足亚目种海豹科动物的统称，常见的有斑海豹、港海豹、冠海豹等。

成纺锤体型、四肢特化成鳍状的哺乳动物，海豹的头圆颈短，没有外耳廓，因为它们的脸部长的像猫从而得名海豹，以区别鳍足亚目其他两个科（海狮科、海象科）的动物。最大的海豹是象海豹，这种海豹雄性有一个鼻囊，可以自由伸缩，也因此得名。

The earless seals or true seals are one of the three main groups of mammals within the seal superfamily, Pinnipedia. All true seals are members of the family Phocidae /ˈfoʊsᵻdiː/. They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are mostly confined to polar, subpolar, and temperate climates. The Baikal seal is the only seal found exclusively in fresh water.