Young: Most baby marine mammals are taken care of, protected, and fed milk by their mothers for several months. Some fish build nests and guard their young, but most do not care for their young at all. They hatch and live on their own immediately. Most fish lay hundreds or thousands of eggs each year! Swim: To move through the water, many marine mammals use their tails and flukes to move up and down.
When fish swim, their spines and tail fins move from side to side. Limbs: Have you ever seen a fish with arms and legs? Neither have we. The bones of an orca flipper even look like finger bones. In addition to these adaptive radiations of both mammals and fish, the scientific base for classification is important.
Mammals evolved with birds, from the reptiles. And the most evolved group of animals are the mammals with more than extant species. They are warm-blooded, that means body temperature of mammals is maintained at a constant level without changing it according to the environmental temperature.
Therefore, the physiology of the mammals does not change and which has been extremely important for them to survive long ice ages without being extinct. It is a bony skeleton in all mammals, and sometimes there are cartilaginous structures present within bones.
The gills are present during the foetal stage and after birth the lungs become functional until the death. Some of the most interesting features of mammals are the presence of hairs, sweat glands, and mammary glands.
The name, mammals, is because of the presence of mammary glands which are functioning to feed the newborns. With the presence of mammary glands along with some other behaviours; mammals do care on their young with great courage and love.
Fish are cold-blooded, so their body temperature changes depending on the temperature of their environment. Whales actually breathe air with lungs using their blowholes to breath out! They come to the surface of the water so they can breathe just like you and me. Fish get oxygen directly from the water through their gills. Whales even have a little bit of hair on their smooth skin, usually on the top of their head.
Fish have scales. Whales even give birth to live baby whales that will get milk from their mom for food. Fish lay eggs, which must still grow into a baby fish. So whales are indeed mammals and not fish! Whales are mammals because they share the characteristics of other mammals like us!
These characteristics include being able to regulate their own body temperature unlike cold-blooded animals, like lizards , growing hair and producing milk to feed their young who are born live, not in eggs. Because of all of these traits, even though whales live in the ocean and are generally much bigger than us, just like people, they are mammals. Why are whales mammals and not fish? What are the characteristics of mammals?
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