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Why big cats roar while small cats purr
It turns out the secret lies deep inside a cat's throat. Small cats like house cats have a rigid bone called the hyoid, which acts like a solid bridge, making it super easy for them to vibrate their vocal cords back and forth to purr continuously. But big cats like lions and tigers have a stretchy, flexible ligament instead of a solid bone. This loose setup lets their voice box stretch out into a giant, booming tube, which is perfect for roaring at 114 decibels, but completely ruins their ability to purr while breathing in.