Did you know that whales and dolphins are mammals? Just like land mammals, whales, and dolphins breathe air. They come up to the surface and breathe through their blowholes. Blowholes are a large nostril flap on top of their heads. Dolphins and whales are similar to land mammals because they feed their babies with milk from their bodies.
Sea mammals either have no fur or very little fur. They have bodies streamlined for swimming. Dolphins, whales, seals, and other sea mammals all have flippers on each side of their torso and tail fins to help them cut through and propel themselves through the water. Dolphins and Orca whales also have fins on their backs Orcas, dolphins, seals, whales, and sea-lions can all hold their breath underwater for a long time.in fact, Orcas can hold their breath for up to 90 minutes. Seals can hold their breath for up to an hour. And walruses can hold their breath for up to 25 minutes.
Dugongs, another sea mammal, are known as “sea cows”. They are chunky, weird-looking animals. They are like cows because they are large, have square snouts, and eat sea grass. Dugongs, though, eat seagrass and are the only vegetarian mammals in the sea. Most sea creatures swim away from attackers, but dugongs can group together and head-butt them.
Sea creatures can be very similar, but they also are very different, especially the sea mammals.
[Source: Amazing Animal Facts]