Fossilized skin pigments from an 85 million-year-old mosasaur, a 193 million-year-old ichthyosaur and a 55 million-year-old leatherback turtle have revealed the skin color of these extinct marine reptiles. This is an artist’s impression of a dark-colored ichthyosaur, mosasaur, and prehistoric leatherback turtle:mosasaurs and leatherback turtles had a dark back and light belly, whereas ichthyosaurs, similar to the modern deep-diving sperm whale,...