![SciShow on Twitter: "Once in a blue millenium, a species trait thought to be lost forever, such as hind limbs on whales, pops up again and teaches us a lot about how SciShow on Twitter: "Once in a blue millenium, a species trait thought to be lost forever, such as hind limbs on whales, pops up again and teaches us a lot about how](https://pbs.twimg.com/media/EagIombXsAcFOFi.jpg:large)
SciShow on Twitter: "Once in a blue millenium, a species trait thought to be lost forever, such as hind limbs on whales, pops up again and teaches us a lot about how
![anniecrawley on Twitter: "The surface separates us from this knowledge holding millions of years of evolution. I captured an image that you could almost see the whale walking in the water. Their anniecrawley on Twitter: "The surface separates us from this knowledge holding millions of years of evolution. I captured an image that you could almost see the whale walking in the water. Their](https://pbs.twimg.com/media/EEdUoRaVAAAPfD6.jpg:large)
anniecrawley on Twitter: "The surface separates us from this knowledge holding millions of years of evolution. I captured an image that you could almost see the whale walking in the water. Their
![This 36-Million-Year-Old Fossil Is a "Missing Link" in Whale Evolution | Smart News| Smithsonian Magazine This 36-Million-Year-Old Fossil Is a "Missing Link" in Whale Evolution | Smart News| Smithsonian Magazine](https://th-thumbnailer.cdn-si-edu.com/Q0KJ9EadMJIz8CJEgC6qKvzynzo=/fit-in/1600x0/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer/1a/a8/1aa88afe-a4ce-48c1-90cf-44a55d401f04/whale_illo.jpg)