Whales have existed for millions of years. Did you know that whales lived on land millions of years ago and then in the water? The first whale like animal to live on Earth was Pakicetus, which lived 48 million years ago. This animal searched widely for food in streams. It was 1.75 meters and 6 feet long. Its nostrils were very far forward and right on top of its mouth. Also Pakicetus had forelimbs and hindlimb walking. It didn't have tail flukes. Then Pakicetus evolved into Ambulocetus 47 million years ago. Ambulocetus was alligator like and fed in water. It was 14 feet long. It also had forelimbs and hindlimbs for walking. In addition, it did not have any tail flukes. 1 million years later Ambulocetus evolved into Maiacetus. Maiacetus was like a sea lion and spent some time on land. This creature was 10 feet long. It had forelimbs for walking and swimming and had very large hind limbs. Just like the others it had no tail flukes. Maiacetus had small sharp teeth. 37 million years ago Maiacetus evolved into Dorudon. Dorudon was completely aquatic and did not go on land at all. It was 15 feet long. The nostrils of Dorudon was not at the front it was farther back on the skull. It didn't have forelimbs; it had flippers. The body of Dorudon started to become like a whale. Dorudon's hind limbs were very small. This creature did have tail flukes. After Dorudon came Llanocetus which was 34 million years ago. Just like Dorudon this animal was also aquatic. Llanocetus was 30-33 feet long. The teeth of this animal were very small. Llanocetus was the first evidence of baleen for filter feeding. The nostrils were all the way back on the skull. Since whales evolved rapidly the environment also changed. All of these whales come from the same ancestor one that walked on land.