Whale

Whale is a group of mammals that live in the ocean. The title "whale" was given to the member nations that are large cetaceans. The whale is not classified in the family fish. The whale has the following characteristics: 

• Breathe using lungs 
• Have hair 
• Warm-blooded 
• Have mammary glands 
• Have a heart with four chambers 

Ancient whales evolved in the mid-age Eocene, about 50 million years ago. One of the earliest whales are extinct is Basilosaurus that has billed a small head and protruding teeth. Basilosaurus 25 meters in length. 


Fossils indicate that whales came from hoofed land animals, the possibility of such mesonychids animals (animals like wolves who live on the coast) that gradually returned to inhabit the seas around 50 million years ago. One more possibility of other animals that turned into a whale, is Ambulocetus, a dog-sized marine mammals but has a 3 meter long weighing 325 pounds. 


At present there are two groups of whales, the toothed whales (Odontoceti) and not toothed whales (Mysticeti). Odontoceti-toothed whales are a predator that eat fish, squid, and marine mammals, has a breathing hole. Toothed whales closely related to dolphins and Irrawaddy. 


Toothed whales are not larger than toothed whales and have a structure known as baleen shaped brush. This structure is useful for filtering plankton, the food, in water. Pope berbalin has two breathing holes.