Giant Great White Shark Eaten By Sea Monster Mystery Finally Solved

Let's dive into how this great white shark eaten by a giant sea monster mystery was finally solved!

April 28, 2023・

19 min read

Great white sharks are feared and revered as the deadliest, most ferocious creatures that lurk in our oceans. But despite being at the top of the aquatic food chain, it turns out even they’ve got something to fear.

Back in 2003, Australian scientists studying the toothy terrors attached a tracker to a huge, nine-foot-long great white to see what it got up to. However, just four months later, the tracker washed up on a beach, without the shark! Unbelievably, something had eaten the beast.

But what kind of super predator could possibly be so powerful it chowed down on one of the most terrifying creatures in the world and left nothing behind? From a lost megalodon to a giant squid, let's take a deep dive into this spooky mystery, as we try and find out exactly what ate the giant great white shark!

The Shark Alpha Tag

It all started back in 2003, when filmmakers Dave and Jennene Riggs were filming a nature documentary on a beach in Bremer Bay, Australia. Everything was going as planned, until suddenly they came across a highly distressing sight. Nine huge sperm whales lay beached on the shore, utterly lifeless.

But that wasn’t all. When Dave and Jennene approached, they realized they weren’t the first ones to notice the whales. Swimming in the shallows, much closer to land than normal, were a hoard of hungry great white sharks. They must’ve smelt the whale carcasses and come over to feed!

While most of us would’ve gotten the heck out of there, Dave sensed a golden opportunity. He got on the phone and alerted a team of scientists, who quickly arrived at the scene with geo-tagging equipment.

By tagging the sharks, they’d be able to follow their movements and learn valuable information about their migration patterns! So, the team got to work. After manning a boat over to the sharks, they used long poles with special needles on the end to insert tags at the bases of the great whites’ dorsal fins.

The first shark they tagged, they named “Shark Alpha,” a nine-foot-long female. Little did they know, what started as a simple study of migration would lead to one of the biggest enigmas in the marine world.

Great White Shark Eaten Whole

Just four months later, Shark Alpha’s tag washed up on the shore, with no sign of the shark itself. Confused, the researchers analyzed the data they’d collected from it and uncovered something astounding.

Around midnight on Christmas Eve, the shark had been swimming along as normal when it abruptly changed course. For some reason, it then started rapidly plunging deeper and deeper into the ocean, until it hit a dizzying depth of around 1,900 feet. That’s almost 1,000 feet deeper than great whites usually go!

Seconds after hitting this depth, the tag’s temperature readings jumped from the surrounding water temperature of 46 degrees to 78 degrees Fahrenheit! The experts doing the analysis were shocked and perplexed but they all came to the same startling conclusion. The tag must’ve wound up in the warm belly of a far larger and faster super predator.

And Shark Alpha itself wasn’t exactly small. Packed with nearly a ton of muscle, its immense strength would’ve made it an incredibly tough opponent. Yet something had easily overpowered the shark, seemingly dragging it into the deep, where it ultimately met its terrifying end.

So, whatever has eaten it must’ve been nigh-on unstoppable! But how do you crack a mystery so incomprehensible it has stumped scientists for years? Our only clues lie in the data captured in the shark’s final moments, and there’s a lot to unpack.

The Seach For The Ocean's Super Predator

From day one, nobody was more eager to find out the truth than Dave Riggs. Dave became fascinated with the location of Shark Alpha during its last breaths in Australia’s wild Southern Ocean, and believed the answers lay hidden there, in a place he’s called “the kill zone”.

This zone is a vast undersea valley, which plummets to a daunting depth of almost three miles. That’s more than twice as deep as the Grand Canyon. And it’s absolutely teeming with life. Natural gasses and nutrients emanating from the Earth’s crust attract thousands of small life forms to the seabed.

Because of this, hungry predators swarm to the zone too, looking for their next meal. The result? A deep-sea death valley, brimming with great whites, killer whales, and giant squid all fighting for supremacy. That’s the stuff of nightmares.

Unperturbed by this terrifying broth of sea monsters, Dave decided he was going to have to go down there himself. There’s a fine line between bravery and lunacy, and I reckon ol’ Davey definitely crossed it.

Knowing that to dive without specialist equipment would be a death wish, he built his own makeshift underwater vehicle for the mission. Equipped with a metal frame, parts from an old lawnmower, and five layers of protective fiberglass, it could theoretically withstand attacks from even the deadliest ocean creatures.

Despite the dangers, Dave assembled a team of people as crazy as he is, and they clambered into the homemade contraption, ready to venture into the unknown. Just minutes after taking the plunge, it was obvious that the expedition would be even more difficult than they expected. Sharks and killer whales swam everywhere.

Just 65 feet below the surface, the divers found themselves among around 40 copper sharks and a whole pod of killer whales, or orcas. If they stayed there much longer, they risked coming under attack from so many animals that they wouldn’t stand a chance.

So, before they could properly investigate the area, they were forced to abandon the mission and go back to the surface. But it wasn’t a complete loss. They’d discovered that two predators were very abundant in the kill zone: killer whales and copper sharks. Could either of these be responsible for turning Shark Alpha into fin-soup?

Copper sharks rarely exceed the size of standard great whites, so it’s highly unlikely one would’ve been able to take down Shark Alpha with such ease. However, killer whales are an entirely different story. With the potential to grow to the colossal length of over 30 feet, these oceanic goliaths would have no problem tackling a great white less than a third of their size.

In fact, they’re known to be their only natural predators! What’s more, killer whales are easily fast enough to pursue sharks in a chase. Even though it seems like the answer’s obvious, nothing’s ever that easy.

If you remember, the data collected from the tag showed that our victimized shark bit the bullet at a depth of 1,900 feet, yet killer whales are surface hunters. They seldom dive greater than a few hundred feet to look for food, so that just doesn’t mesh with what actually happened.

Moreover, similar to us humans, orcas have an internal temperature of around 100 degrees Fahrenheit. But the tag was swallowed up at a heat of just 78 degrees Fahrenheit. So, the shark’s predator couldn’t have been a killer whale. but if it wasn’t an orca, what could it have been?

Despite its enormous size, the next suspect likes to keep a suspiciously low profile. Lurking in the dark depths of the deep sea, is the giant squid. These strange and intimidating behemoths are something of an enigma to scientists. Because they live so deep underwater, it’s exceptionally difficult to study them.

Yet, where better to look for a mysterious unknown killer than the most unexplored part of the ocean? And even more intriguingly, giant squid live between 1,000 and 2,000 feet below the surface. In other words, at the same depth Shark Alpha met its end in!

So, how does the giant squid match up to the great white? Well, for one, it’s absolutely huge. The largest one ever seen measured 59 feet in length and weighed almost a ton. That’s a whopping ten times the height, and weight, of the average man! And squids have some seriously powerful tentacles too.

Ones they could easily wrap tightly around a shark, especially armed with all those grippy suckers. In fact, giant squid can snatch prey from up to 33 feet away with their long feeding tentacles! Typically, they prey on smaller fish and shrimp, however new evidence has come to light showing that sharks aren’t necessarily off the menu.

In 2020, a whitetip shark was found covered in huge tentacle marks, the kind that could only have been made by a huge squid. That particular shark got away with its life, but how many others weren’t so lucky? With such limited research available, it’s hard to say. But giant squid have also been known to demonstrate something called diurnal vertical migration.

Essentially, they rise to the surface at night to hunt for food, then return to the depths during the day to sleep, safe from any potential predators. So, in theory, a massive squid may have risen to the surface, spotted shark alpha, and dragged the unfortunate fish down to its deep-sea habitat to gobble it up for dinner!

However, that's still not an accurate match. The fly in the ointment lies in that sharp increase in temperature when the shark got gobbled. It indicates that it was eaten by a warm-blooded creature, with an internal temperature higher than its environment.

But giant squids are cold-blooded, and their body temperatures are dependent on the temperature around them, meaning if the tag had been sitting in one’s digestive system, it would’ve shown a temperature more similar to the water’s. That does mean however that we’ve ruled out the most likely candidates.

Mysterious Deep Sea Monsters

It’s time to get a little more creative with our thinking. Although today, killer whales are the only known natural predators of great white sharks, historically, a whole host of shark-eating creatures have roamed the oceans. So, is it possible that a supposedly extinct being is responsible for the mysterious attack?

Considering an astounding 80% of the ocean is still unexplored, this theory may not be as ridiculous as you first think. Take the Spinosaurus. This intimidating beast was the largest predatory dinosaur to ever walk the earth, reaching the monumental length of 50ft, and standing almost 18ft tall!

And it didn’t just walk; it was equipped with huge paddle-like feet to help it swim, and sealable nostrils to stop water from getting in. In fact, this dino is thought to have been capable of swimming underwater and eating sharks whole.

So, theoretically, if one managed to get near enough to a great white, there’d be no question, it’d be shark sushi for dinner. There is the slight issue of it not being seen for some 72 million years or so, but the deep ocean is a mysterious place.

Regardless, Spinosaurus were only semi-aquatic, so they probably couldn’t swim underwater for very long. Thus, if one was out there, it wouldn’t be able to dive to the depths Shark Alpha did, and we’d definitely have seen it wandering around by now, so we can safely rule this one out.

The Mosasaurus on the other hand was likely very comfortable swimming in open waters. This ferocious ocean predator lived at the same time as the Spinosaurus, but it fits the profile for our secret shark slayer much better. With the biggest reaching huge lengths of over 50ft, they were an imposing sight to behold.

What’s more, their flipper-like limbs and long, shark-like tails meant they could rocket through the water at tremendous speeds of at least 30mph. While this is only slightly faster than a great white, Mosasaurus are far, far bigger. So, it’s safe to say one could easily chase down and hunt a shark to devour with a terrifying set of razor-sharp teeth.

In fact, if you’re wondering what would happen in a battle between these guys, that wouldn’t even be a battle. A mosasaurus could be over five times as long as our shark, and more than 10 times as heavy! That shark would definitely be going down.

Of course, this wild theory hinges on seafaring super-reptiles having secretly survived underwater all this time. Could something like that be possible? When the asteroid crashed into Earth and wiped out the dinosaurs some 66 million years ago, wouldn’t the sea creatures have been protected by all that water?

Naturally, the water would’ve shielded some from the initial blast. But even those that did survive were doomed from the start. That’s because the meteorite increased carbon levels in the atmosphere and sent acid rain pouring down, which steadily acidified the oceans over the course of hundreds of years.

Eventually, this acidification became so severe it led to the mass extinction of almost all ocean organisms, as they couldn’t survive in the harsh conditions. So, the chances of a Mosasaurus managing to escape that fate is so low it’s practically zero.

For that reason, any dinosaur-era suspects really can be discounted. But there’s another supposedly extinct creature we just can’t stop thinking about, and unlike the dinosaurs, there are loads of people that reckon it’s still alive today: the megalodon, AKA the largest shark that ever lived.

This beast was truly one of epic proportions, with fossil evidence showing they grew up to 60ft in length. In other words, the size of a large dinosaur! In fact, the colossal mega-shark could open its jaws over 11 feet wide, which is easily big enough to swallow a shark or even two adult humans!

While humans weren’t alive back when megalodons were common, over 3 million years ago, sharks certainly were, and scientists agree they’d have been on the menu. Which isn’t hard to believe when you see the size of the teeth that lined Megalodon's huge jaws. Check the photo below for a comparison between the tooth of a great white and a megalodon.

Combined with its speed and immensely powerful bite, it’s one of the meanest predators to have ever existed. So, you’d imagine it wouldn’t just disappear without at least a fight. Considering it’s essentially a massive shark, couldn’t it still be lurking somewhere in the deep sea?

It wouldn’t be the first time that a fish was falsely declared extinct. Coelacanth, a small deep-sea fish found around the coast of Africa, were thought to be extinct until as recently as 1938, when they were rediscovered! However, it’s not hard to lose track of a tiny population of small fish that live deep within the ocean, but megalodons were bigger than a school bus.

Plus, scientists think they spent most of their time in shallow, coastal areas. In other words, where we’d be able to see them. Though, just because we haven’t seen them doesn’t necessarily mean they’re extinct. There’s a chance that the ancient beast has evolved over millions of years, and now lives in the deep sea.

This is technically possible. We didn’t become homo sapiens until only around 300,000 years ago, but just as we look very different to how we used to, if the megalodon was alive today and secretly living in the deep, it’d probably look a whole lot different too.

Sea life that lives near the ocean floor has to make do with surviving off of the scant species that live there. As a result, any sharks that have evolved to live at such depths are typically very slow moving. That way, they don’t need much food to survive and won’t exert unnecessary energy in their movements.

So, if the megalodon really has successfully adapted to a deep-sea life, it’d probably look more like a sleeper shark. These are unaggressive, slow-moving animals, and are generally, a lot less badass than a traditional megalodon.

In other words, it's unlikely that an evolved, modern-day megalodon would have the speed and explosive power needed to be able to chow down on a nine-foot-long great white shark. However, I have a few more theories up my sleeve. For starters, we can’t discuss the most powerful ocean predators without mentioning the Livyatan Melvillei.

This is a supposedly extinct type of sperm whale that may have been able to give even the megalodon a run for its money. With gargantuan teeth coming in at up to 14 inches long, if you exclude tusks, it had the largest gnashers of any animal alive or dead!

Scientists assume this freakishly large creature could’ve eaten anything it wanted, including sharks and other whales. Which isn’t surprising when you realize one tooth is about the size of a bowling pin.

The 60ft-long super-whale has apparently been extinct for nine million years though, something that’s pretty widely accepted. Even so, scientists do make mistakes. And the exact reason this whale went extinct is as murky as the waters it lived in. It’s been theorized they died out due to a global cooling event, as much of their prey were unable to survive in the cooler waters.

But then, why did other sharks and whales survive, when they were preying off of the same food source? It could’ve been down to the Livyatan’s colossal size; it needed far more food to survive than smaller sea predators. But no one knows for sure.

Furthermore, there's one final nail in this theory’s coffin. Just like modern dolphins and whales, Livyatan Melvillei couldn’t actually breathe underwater; they had to come up to the surface. So, if these things really weren’t extinct, they’d be popping up all over the place to grab some air! And, considering their size, it seems pretty unlikely they’d have gotten away with it unseen for nine million years.

The Bloop

There is one thing, however, that has made scientists far and wide question if there really could be some kind of extinct being skulking in the far corners of our oceans. It’s called “the bloop”. The name was given to a mysterious sound heard by researchers back in 1997. They’d been listening out for volcanic activity in the Southern Pacific Ocean when they picked up a strange, extremely loud sound unlike anything they’d ever heard before:

So, you might not think that could’ve come from an animal. But you’d be surprised just how many weird noises animals are capable of. Take the Black Drum fish. It makes the strange sound using special muscles that vibrate against their swim bladders.

So, it’s not out of the question that a much bigger creature could’ve made a far louder, more alien sound. Perhaps something we haven’t even discovered yet!

Of course, when conspiracy theorists caught wind of the bloop, they jumped to some pretty wild conclusions. It was recorded near to where the fictional sunken city of R’lyeh is supposedly located, the prison of H. P. Lovecraft’s mythical sea monster, Cthulhu.

Because of this, some horror lovers believed it could point to the giant tentacled beast being real. While Cthulhu would have no trouble with a great white shark, it’s also definitely not real.

The real source of the bloop took years for scientists to figure out, but eventually, they did. And for better or worse, it wasn’t a huge unknown creature. It was actually something far more pedestrian; the sound of sea ice cracking and breaking, which is a common occurrence in the Southern Ocean.

It turns out, the audio that was originally released to the public had been sped up to 16 times its normal speed. The original sound was quite different from the sped up version.

Mystery Solved

While we've had a fun ride investigating the mystery, we might've known what ate it all along. In truth, the case was blown open back in 2014, over a decade after Dave and Jennene first stumbled across the dead whales that started this whole crazy saga. And the real answer is just as horrifying as any of the theories above.

After turning their attention to the migration patterns of other great white sharks swimming through the kill zone, researchers realized something shocking. The tracking information from those sharks matched the patterns shown by Shark Alpha’s tracker!

The jump in temperature of the tracker, an enigma that had stumped scientists for years, suddenly made sense. The temperature it had jumped to was the same as the internal temperature of a great white shark!

Of all the possible solutions, nobody had ever thought that another great white could’ve been responsible for the attack as they’re just not big enough! But this is where it gets really messed up. Shark Alpha wasn’t eaten by an ordinary great white shark, it was eaten by a colossal, 16ft-long cannibal great white.

The cannibalistic super-shark must’ve had a condition called gigantism. This is where an animal suffers from abnormally high levels of growth hormone, causing it to grow nothing short of enormous. As well as being 16ft long, it could easily have weighed over two tons, more than twice the weight of Shark Alpha.

As to why it ate one of its own kind, it’s not that uncommon for regular sized sharks to feed on smaller ones. So, it figures gigantic sharks would eat normal sized ones! But you may be thinking, if great whites don’t usually dive as deep as the 1,900ft shark alpha died at, why did this huge specimen drag its victim so deep?

Well, we don’t know for sure. However, while it is rare, great whites have occasionally been known to dive deeper than 4,000ft, and due to the timing of Shark Alpha’s temperature spike, we do know the super-shark only ate its prey at the end of the dive. So, it’s likely it grabbed the smaller shark in its jaws and rapidly plunged with it to disorient it and make the final kill that much easier.

Before you vow never to enter the ocean again though, there is one shred of comfort I’ll leave you with. Sharks generally aren’t interested in eating humans, so you’ve probably got nothing to fear from this colossal cannibal great white. However, there are certainly a million better places to swim than Bremer Bay’s kill zone.

If you enjoyed investigating the mystery of the super predator that devoured the great white, you might want to read this article about the largest sea creatures that ever existed and this article about creatures more terrifying than megalodon living in the mariana trench. Thanks for reading!