Whale watchers on a cruise in Cape Cod had their afternoon plans abruptly changed from watching a whale to watching two sharks hold a whale-eating contest.

Guests about the Hyannis whale-watching cruise were “in complete awe” when their whale-watching expedition turned into shark-watching expedition as the whale they’d come to see was recently deceased. Although it wasn’t because of the sharks.

On October 14th, marine biologist Joanne Jarzobski hitched a ride aboard the Hyannis cruise along with 160 other passengers to investigate reports of a dead fin whale floating in the bay. She’d been tasked by the Massachusetts Division of Marine Fisheries and the Center for Coastal Studies in Provincetown to investigate the whale and report back on her findings.

The cruise ship set sail, and roughly 7 miles north of Barnstable Harbor spotted the fin whale carcass. However, stunned whale-watchers were astounded to find two more marine animals: a pair of great white sharks feasting on the enormous corpse.

One of the sharks was at least 18 feet long (and possibly longer, according to the Boston Globe), while the other was a smaller great white. Both were gorging themselves on dead whale blubber, which is an important part of the great white’s diet.

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While younger, smaller great whites consume fish and small marine mammals, larger great whites become too large and cumbersome to hunt more nimble prey such as seals and dolphins. Instead, they seek out whale carcasses to consume, focusing on the fattiest parts of the whale in order to get the most calories per bite.

Great whites have been known to feast for hours until they become bloated and lethargic--much like most American families during Thanksgiving. The only difference is sharks leave less of a mess to clean up afterward.

However, sharks feeding in this way is a rarely seen occurrence as whales tend to die in remote ocean areas.

“Getting the opportunity to see a great white shark in action is truly a once-in-a-lifetime experience for our passengers and crew,” said Jarzobski.

Researchers are now attempting to identify the fin whale and determine just exactly how it died.

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