Natural Born Enemies? Aug. 15, 2008 -- Adult polar bears, among the largest and most powerful carnivores, are thought to have no natural enemies, but that assessment might change in light of a polar bear jawbone recently found in the stomach of a Greenland shark.
While Greenland sharks, which can grow up to 24 feet long, are known to have eaten large seals, porpoises, an entire reindeer and parts of a *****, the discovery is rare evidence that they may also feast upon polar bears.
