Few things could slay a giant beast wielding teeth the size of kitchen knives, but a new discovery reveals that arthritis was one of them. Scientists examined the massive, pointy jaw of an ocean-dwelling pliosaur (artist's conception, right), a whale-sized reptile with a head like a crocodile, and concluded that the animal suffered from a degenerative joint condition that likely proved fatal. The disease wore away the left jaw hinge (left) of this 8-meter-long behemoth, causing its lower jaw to hang askew. The crooked-mouthed animal kept on biting, living long enough for its misaligned 20-centimeter-long teeth to etch grooves into the jawbone. But signs of an unhealed fracture indicate that the jaw eventually snapped apart, rendering the animal unable to feed, scientists report today in Palaeontology. The finding illustrates that the death of ancient beasts wasn't all ferocious battles and doomsday asteroids—they, too, suffered the mundane wear and tear of old age.
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