The leatherback turtle (top) and mosasaur (bottom) are countershaded (have a dark back and light belly), whereas the ichthyosaur (center) is uniformly dark-colored. Credit: Stefan Sølberg
The leatherback turtle (top) and mosasaur (bottom) are countershaded (have a dark back and light belly), whereas the ichthyosaur (center) is uniformly dark-colored. Credit: Stefan Sølberg
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