If there’s one place on Earth that’s still full of mysteries after all this time, it’s definitely the ocean.

And just when scientists think they at least know what animals in the deep are the biggest, a tracker affixed to a female porbeagle shark ends up in something even larger.

The shark in question was around seven feet long and a very capable predator, which means researchers are keen to track down what took her out.

A team trying to solve the mystery says this is pretty much an unprecedented event.

“This is the first documented predation event of a porbeagle shark anywhere in the world.”

Porbeagle sharks live in the Northwest Atlantic and can grow up to twelve feet in length. They can weigh 500 pounds, though are usually a bit smaller, and live for an average of 30 to 40 years.

Until now, researchers have imagined they have very few – if any – natural predators.

Two trackers were affixed to this shark in 2020, one on a fin that broadcasts its location whenever the shark is at the surface, and the other a pop-off satellite archival tag (PSAT).

The latter records depth and temperature measurements that are stored until the tag “pops off” and floats to the surface.

This shark’s PSAT detached before researchers expected, and the data showed she had been swimming at 2,000-2,600 feet during the day and 300-600 feet during the night. Water temperatures ranged from 43° to 74°F.

In March of 2021 the temperature stayed at 71 degrees for four straight days, which pretty much had to mean the shark had been eaten.

The most likely culprits are a shortfin mako shark or a great white.

Shortfin mako sharks are twice as heavy as porbeagles and are known to prey on smaller sharks in addition to their regular diet of fish, cephalopods, and sea turtles.

Great white sharks are obviously much larger – they weigh over 4,000 pounds – typically favor larger prey like whales, dolphins, and seals.

Since the tracker didn’t show signs of a mako shark’s typical diving behavior, researchers are betting on the great white – and that, they say, is worrying.

“If predation is more widespread than previously thought, there could be major impacts for the porbeagle shark population that is already suffering due to historic overfishing.”

Porbeagles, like almost all sharks, have slow reproductive cycles, so if great whites start snacking on them, it could spell trouble.

It certainly did for this poor pregnant gal.

Thought that was fascinating? Here’s another story you might like: Why You’ll Never See A Great White Shark In An Aquarium