The story of a mysterious super-predator that attacked a 9-foot great white shark went viral on Monday following the release of a clip from the Smithsonian documentary "Hunt for the Super Predator."

According to the video, changes in temperature and ocean depth recorded by a tracking device that washed ashore after being attached to the shark seemed to indicate that the tag had been inside the stomach of another animal.

Internet speculation quickly spread, with many assuming that the entire shark was consumed by a much larger shark. Some even wondered if the shark had been devoured by a legendary creature known as Megalodon, a 64-foot shark that went extinct millions of years ago.

But CSIRO, the Australian science agency leading the effort to tag and track white sharks, set the story straight in a blog post on Wednesday.

In late 2003, scientists attached a tag designed to collect data on swim depth, water temperature, and light levels to the 9-foot shark, Kirsten Lea from CSIRO explained. The tag surfaced two weeks before it was programmed to detach from the creature.

Over a three-week period the tag recorded temperature "consistent with that of the core body temperature of a white shark but too low for something like a killer whale," Lea wrote. Many batted around the theory that the shark was eaten by a killer whale.

"All evidence suggests that the tag had been eaten by another white shark," Lea said. "We concluded that this was the most likely explanation – one shark bit off a little more than he could chew and ended up swallowing the tag." She added: "We never concluded that the 3m shark was consumed by another much larger shark."

Lea also pointed out that shark-on-shark attacks are not uncommon. "We have seen white sharks biting each other before, sometimes removing pieces of tissue in the process."

David Shiffman, a marine biologist studying sharks at the University of Miami, agrees with this view. "We don't know for sure what happened in this case," he said in an email, "but large sharks eat smaller sharks all the time."

You can read Lea's full blog post here »