FC: KRISTIN LE | & | WATER MAMMALS | 4B
3: Water mammals are animals evolved from mammals on land, making a return to the ocean, some of their ancestors are elephants and other land animals Water mammals have the same characteristics that make a mammal, such as hair, warm blood, lungs, mammary glands, live birth, and a hinged jaw. More specifically Marine mammals have a way to keep themselves warm, and are highly adapted to swimming.
4: Marine mammals are a diverse group of 120 species of mammal that are primarily ocean-dwelling or depend on the ocean for food. They include the cetaceans (whales, dolphins, and porpoises), the sirenians (manatees and dugong), the pinnipeds (true seals, eared seals and walrus), and several otters (the sea otter and marine otter). The polar bear, while not fully aquatic, is also usually considered a marine mammal because it lives on sea ice for most or all of the year.
7: Since mammals evolved on land, their spines are made for running, allowing for up-and-down but only little sideways motion. So, marine mammals typically swim by moving their spine up and down.
8: Marine mammals breathe air, while most other marine animals extract oxygen from water. Marine mammals have thick layers of blubber used to insulate their bodies and prevent heat loss. Sea otters and polar bears are exceptions, relying more on fur and behavior to stave off hypothermia. Marine mammals give birth. Most marine mammals give birth to one calf or pup at a time Marine mammals maintain a high internal body temperature.
10: Between oceans, rivers, seas and lakes, the water is home to a large percentage of the animal species of the world. Of the many water animals, a great many are mammals. Though they need to breathe oxygen and birth live babies, mammals that live in the water have adapted to be able to live in an aquatic habitat.
12: There are 32 different dolphin species. There are 22 species of true seals. There are 79 to 84 species of whales.