When most animals were growing arms and legs and climbing out of the water, whales were growing fins and walking into the water. Whales changed, or evolved from warm-blooded, air breathing animals that lived on land to ocean dwellers. Their earliest known ancestor looked like a short antelope with hoofed feet. This mammal had a bone in their ears that is still found in whales today.
HOW DID IT HAPPEN?
About 57 million years ago, certain animals lived near the sea and would hunt just off the shoreline for fish. Because the sea was not very deep they could do this easily. When they needed to go into the deeper waters, the whale’s ancestors that were the best swimmers survived. They reproduced in greater numbers than those who weren’t good swimmers.
Slowly, over millions of years, these creatures changed into animals that spent more and more time in water. Gradually, their front legs became smaller and were useful as flippers, while the hind feet became larger and helped move the animal through the water. They further evolved for diving and hearing under water. Smooth skin and loss of protruding ear parts and hind limbs streamlined whales for swimming. The nostrils moved to the top of the head to make it easier to breath and swim at the same time. A layer of blubber replaced hair for warmth.
HOW BIG DO WHALES GET?
Some whales are the largest living creatures ever to exist on earth. The body, supported by water, is able to reach enormous size. They can grow bigger than the biggest dinosaur. An elephant could sit on a blue whales tongue. Its heart is the size of a small car! A blue whale weighs over 150 tons. The longest whale measured in at over 110 feet. If you laid him out on the ground he would take up the length of nine family-sized cars!
REMNANTS FOUND IN TODAY’S WHALE!
Inside the fin of a modern whale, you can still find the bones of an arm and hand. Today’s whale is also equipped with a pelvis bone, which is not needed anymore. And unlike fish, modern whales have lungs and nostrils called blowholes, and must surface occasionally to breathe.
Paleontologists have found key remains of bones and skulls that help to prove whale evolution. Fossil records continue to be documented. Whales certainly changed in a most unusual way. By reversing the water to land trend of most animals, and becoming an efficient mammal for ocean life, it is one of the most fascinating evolutions of all time.
To learn more, check out: http://www.whale-world.com/whale-evolution.html