Whale sharks are the biggest fish in the sea, but their size isn’t the only thing they have in common with whales. These gentle giants only eat plankton, just like baleen whales! But instead of baleen, whale sharks use a clever system hidden in their gills. As they swim, they suck seawater filled with plankton, krill, and small fish into their enormous mouths. Then, with a quick close of the mouth, the water is pushed out through their gills. Inside, thousands of bristly gill rakers act like sieves, trapping food and letting the water escape. Their filtering method is called “cross-flow filtration,” meaning water moves across the surface of the filter rather than straight through it. This helps prevent clogging, keeping the system efficient. When the rakers do get overloaded, whale sharks have even been seen “coughing” to clear them out. Although they have thousands of (very) tiny teeth, they don’t use them. They’re just peaceful ocean vacuums, with no threat to humans at all! Vide...