Mosasaurus vs. Spinosaurus : A Battle of Giants

Mosasaurus vs. Spinosaurus : A Battle of Giants

The late Cretaceous period, a captivating epoch 90 million years ago, was inhabited by colossal dinosaurs in a hot and carbon dioxide-rich world. Today, we delve into a comparison of two significant creatures from that era: the Mosasaurus vs. Spinosauruss.

When it comes to size, the average Spinosaurus slightly surpasses the average Mosasaurus in length and weight. The Spinosaurus measures around 55 feet (16.76 m) and weighs 16 metric tons (16,000 kg), whereas the Mosasaurus reaches approximately 50 feet (15.24 m) in length and weighs 14 metric tons (14,000 kg). However, both species can reach extreme sizes of about 60 feet (18.28 m). Therefore, upon examining the largest specimens of each species, which approach 60 feet, it becomes clear that neither monster holds the definitive title. Moreover, the Spinosaurus and Mosasaurus differ significantly in appearance and habitat. Before diving deeper, let's take a brief look at why dinosaurs were colossal in the first place.

The Enigma of Gigantic Dinosaurs

If you had existed just before the catastrophic Chicxulub asteroid impact 66 million years ago, you would have witnessed awe-inspiring giant lizards roaming the Earth, albeit briefly as many of them were carnivores. But why were these creatures so enormous?

Paleontologists theorize that the colossal size of many dinosaurs can be attributed to their hollow bones and massive stomachs. Additionally, their large size likely served as a deterrent against formidable predators.

This explanation represents the current state of scientific understanding. Further attempts to unravel the mystery have resulted in conflicting theories and puzzle pieces that don't quite fit together. For example, the notion that higher atmospheric oxygen levels contributed to growth has been debunked, as the Earth's atmosphere contained less oxygen during the dinosaur era than it does today.

Another hypothesis suggesting an abundance of food as a catalyst for gigantism also fails to hold water, as there were numerous dinosaurs comparable in size to present-day animals. However, it is known that the bones of many sauropods, long-necked plant-eaters that stood on four legs, contained air pockets, reducing their weight while providing enough strength to support their large frames. These sauropods also possessed expansive stomachs capable of storing food for extended periods.

As for being hunted by predators, well, attempting to tackle a titanosaur the size of an office building would be a daunting task. It would take a while, and most T-rexes likely preferred easier prey.

Now, let's delve into the specifics of the two dinosaurs in question.

Is the Spinosaurus Larger Than the Mosasaurus?

To answer this question, let's focus on average sizes rather than extremes.

The average-sized Spinosaurus indeed surpasses the average-sized Mosasaurus, albeit marginally. However, when considering individual specimens, the comparison becomes more evenly matched.

The average size of the Spinosaurus ranges from 50 to 60 feet (15.24 to 18.28 meters) in length, weighing about 16 metric tons (16,000 kg). On the other hand, the Mosasaurus measures around 50 to 55 feet (15.24 to 16.76 meters) long, weighing approximately 14 metric tons (14,000 kg).

It's a close competition, and neither of these formidable creatures would be suitable for exhibition at SeaWorld.

Now, let's take a closer look at each of these colossal creatures individually.

Introducing the Spinosaurus

The Spinosaurus inhabited North Africa over 90 million years ago. This creature was not the friendly type you'd encounter in a dark alley or expect to assist you with carrying bags or holding doors. It was massive, measuring an astonishing 50 to 60 feet (15.24 to 18.28 meters) from head to tail. By comparison, the average Tyrannosaurus rex reached about 35 feet (10.66 meters) in length.

To visualize its appearance, imagine a T-rex with an elongated, tooth-filled jaw measuring about 6 feet (1.82 meters). Add a rigid, humped spine on its back, reaching heights of about 10 feet (3.04 meters) and making the creature nearly 20 feet (6.09 meters) tall overall. Additionally, it possessed a 23-foot (7.01 meters) long tail, which aided its swimming abilities for aquatic hunting.

Now, imagine yourself trying to escape from it as fast as possible. Unless you're Usain Bolt, you won't get far. The Spinosaurus could reach speeds of 15 miles per hour (24.14 kph) on land, while most humans can only manage about six miles per hour (9.65 kph) at best, assuming they're in excellent physical shape.

Spinosaurus on the Hunt

Although the Spinosaurus was amphibious, it predominantly spent its time near water, hunting large fish. It would stand in the shallows and use its long neck and jaws to snatch prey. Modern theories compare the hunting style of the Spinosaurus to that of storks and cranes.

This seemingly mundane tactic for such a ferocious-looking predator is countered by some paleontologists who believe the Spinosaurus hunted similar to modern-day crocodiles, lurking beneath the water's surface and launching swift and deadly strikes. Whichever method it employed, the Spinosaurus's large fin-like spine on its back served to intimidate other dinosaurs interested in its fishing territory. The fin also played a role in attracting potential mates.

However, the fin also proved to be a vulnerability for the creature, as opponents could easily bite into it, causing significant damage given that the fin is an extension of its spine.


When we think of dinosaurs, we often contemplate their eventual extinction. It inevitably leads us to the catastrophic event that occurred 66 million years ago, known as the Cretaceous-Paleogene extinction event.

The Spinosaurus did not witness this event, which it likely would have been grateful for. Instead, its demise can be attributed to a drought that struck its primary habitat in North Africa. Since the Spinosaurus preferred hunting in shallow water, the drought caused much of its hunting grounds to dry up, depriving the creature of its main food source (as it consumed a significant amount of fish). Furthermore, the Spinosaurus proved to be ill-equipped to adapt to the changing environment. Ultimately, the lack of food to sustain its colossal size led to the extinction of this magnificent creature.

Now, let's turn our attention to the Mosasaurus.

Introducing the Mosasaurus

Living in the aquatic realm 80 million years ago, the Mosasaurus was an aquatic predator. Although it called the Atlantic Ocean home, fossils of this dinosaur have been discovered across the globe, from the Netherlands to Missouri, and even Antarctica.

Reconstructed skeletons depict the Mosasaurus as a nightmarish creature from the twisted imagination of Tim Burton. At first glance, one might mistake it for a whale, but upon closer inspection, it reveals itself as an aquatic reptile equipped with a long back, an even longer tail, and four massive fins.

The Mosasaurus boasted a skull measuring just under six feet (1.82 meters) in length, filled with rows of conical teeth capable of tearing prey to shreds. Once dismembered, the prey was devoured in scaly, bloody chunks.

Mosasaurus on the Hunt

So, what did this enormous, cold-blooded terror of the deep feast on? You could say it had a rather voracious appetite. The Mosasaurus devoured a variety of prey that could fit inside its jaws, including sharks, turtles, unsuspecting birds seeking a quick coelacanth snack, and even smaller members of its own species. In short, the Mosasaurus was a formidable bully in its aquatic domain. Better be prepared to surrender your lunch money.

How Big Was the Mosasaurus?

If you happen to suffer from galeophobia, the fear of sharks, you might want to skip this section. While the Mosasaurus wasn't a shark, it bore a striking resemblance. Especially when it comes to size, it surpasses expectations.

On average, the Mosasaurus measured around 53 feet long and weighed just under 31,000 pounds (14,061.36 kg). In extreme cases, these creatures could reach lengths of up to 60 feet (18.28 meters) and weigh closer to 40,000 pounds (18,143.69 kg). Richard Dreyfuss was right: everybody out of the water.

There was hardly a safe place to go swimming during the reign of the Mosasaurus. Fossil evidence and bones of these long-extinct creatures have been discovered all over the world. One particular fossil specimen found in North Dakota, a rather unexpected location, belonged to a Mosasaurus estimated to be 60 feet (18.28 meters) long.

Why North Dakota? Consider that much of North America was still submerged underwater during the late Cretaceous period. It's entirely plausible that the Mosasaurus could have swum up a now-vanished channel to what is now known as the Peace Garden State.


The Mosasaurus lived until 66 million years ago, when an asteroid over three miles (4.82 km) in diameter hurtled from the depths of space. At first, it appeared as a new star in the sky. Over several months, the star grew brighter until suddenly the Earth's shadow fell upon it, rendering it invisible.

But invisible or not, the asteroid carried a message of death. It reappeared one day, brighter than ever, blinding those who looked upon it. The asteroid impacted near Chicxulub, Mexico, resulting in the elimination of 75% of all life on Earth.

Large creatures like the Mosasaurus stood no chance. As the planet was shrouded in a blanket of scorching ash, fires erupted across the surface. These flames were fueled by winds reaching 620 miles per hour (997.79 kph) near the impact area, creating a global cataclysm. The demise of the dinosaurs was swift and unanticipated.

Can Mosasaurus Overpower Spinosaurus?

Ah, the question that ignites the imagination! One can only imagine the value of tickets to witness such a battle. However, pondering this scenario today yields no definitive answer, as it is subject to multiple variables. Additionally, we must remember that these creatures existed in different time periods and would never have crossed paths.

In a hypothetical confrontation, the Mosasaurus could potentially overpower the Spinosaurus, taking into account environmental factors and the size of the opponent. The outcomes of their battles would likely be evenly matched.

I will venture onto the proverbial limb here and assert that the Mosasaurus would never lose a fight against the Spinosaurus in deep water. Its aquatic abilities far exceeded those of the Spinosaurus, which primarily roamed on land.

In reality, the question of who would win in a battle between the Mosasaurus and the Spinosaurus is akin to pondering the outcome of a clash between fire and ice or the Yankees and the Red Sox. It would be epic, it would be glorious, and ultimately, it would be as monumental as the extinction events that prevent us from ever truly knowing.


The Spinosaurus and the Mosasaurus were two colossal dinosaurs of their time. Both shared a diet consisting of fish, although they inhabited different worlds. Their sizes were so closely matched that we might as well call it a draw. The same applies to their hypothetical battles.

As for their fate, the Spinosaurus seemingly perished due to its inability to adapt to a changing environment. On the other hand, the Mosasaurus had no opportunity to adapt, as it fell victim to the devastating asteroid impact. It's evident that their immense size played a significant role in their downfall.

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