Aquatic Mammals and Adaptations | Chordata | Zoology

Mammals are primarily terrestrial animals. However, some of them have adopted an aquatic mode of life. The aquatic mammals have evolved from terrestrial mammals. The fact that all of them are not gill-breathers but breathe air through lungs, indicate their original terrestrial mode of life. All the aquatic mammals are really terrestrial lung-breathing forms which have reverted to an aquatic [...]