Crocodile eyes are built like precision instruments for survival. Set high on their skulls, they let the animal hide almost entirely beneath the surface while still scanning everything above the waterline. Their pupils, narrow vertical slits, can expand wide at night to capture the faintest light or clamp down tightly under harsh sun, giving them a visual edge at any hour.What really sets them apart is a reflective layer behind the retina called the tapetum lucidum. This structure bounces incomi

45K views · 199 reactions | Several U.S presidents came of age during the greatest global crisis of our time. Discover the people behind the power during HISTORY's two-night docu-series, Presidents at War, beginning February 17 at 8/7c. | HISTORY | Facebook