Spinosaurus versus Tyrannosaurus Rex.

Date : 22/10/2014
Version: 0.4
By: Albert

This note is absolutely just for fun. But I hope all details are ok.

If you would ask any person about what the largest, and most fearsome predator was, that ever existed on the face
of the earth, probably most would answer that the "Tyrannosaurus Rex" (T-Rex), is the moste likely candidate .

However, some folks question if it's really true that the "Tyrannosaurus Rex", was the most powerfull carnivor amongst the dinosaurs.
For example, (although probably lesser known to the general public), the "Spinosaurus", was a carnivor that at least outweights the T-Rex,
and is likely to be the largest of all known carnivorous dinosaurs.

Although a question like "Tyrannosaurus Rex" versus the "Spinosaurus", in terms of raw power, might be an interesting question to
a handfull of people, it's ofcourse a rather unscientific and futile question.

First of all, the times that both animals lived, is immensely seperated in time, and so in reality, they never could have met each other
for the "final showdown".
Actually, for the Spinosaurus, the most directly competing rival (in power), was "Carcharodontosaurus", for it was living in the same time area.

"Spinosaurus versus Tyrannosaurus Rex" is not exactly a most relevant question, but I can imagine some of us would like to know, or better, "speculate", anyway!

We will take a look at the "specs" of both animals later in this note. And..., we will see a couple of other candidates too, who must be considerd
to be candidates for the title of most fearsome predator.

So, what are we dealing with here? Or..., What are we trying to answer here?
Maybe that could be nicely illustrated by this clip from the movie "Jurassic Park 3"

Ofcourse, that's just a very entertaining movie, but not always precisely in accordance with scientific principles.

Weigth, length, bite force etc.., is all very important ofcourse, but:

The natural "behaviour" of the predator is very important as well.
A predator which uses "the surprise attack" as it's most prevalent strategy, is likely to win from an equal sized
rival from another species. It seems from the literature, that Spinosaurus was mostly a fisher, while T-Rex might
have been exactly such creature, which have used a quick surprise attacks at it's victims.
However, many folks would suggest that, in a hypothetical confrontation, both creatures might "try" to ignore each other, and both
would have created space between them, because of the "risks" involved of severe injuries.
It's just a fact from what we see today, that opponents also first "size up" each other, and act accordingly.
However, this reasoning is probably only valid using the "classical view" of Spinosaurus (see section 1.1).
Which would have been the "smartest" one? Both animals were certainly powerfull enough, but being intelligent enough
to choose the best moment and place of attack, would have been a large advantage.

New findings with respect to Spinosaurus:

Especially with respect to the Spinosaurus, until very recently, we used to have the "classical view" in place, which made the
animal just "look" like all other dinosaurs. However, in 2014, new findings changed the view radically.
Now, strong evidence points to the fact that Spinosaurus probably had swimming capabilities,
and it might have lead a semi-aquatic life. This changed the view of Spinosaurus considerably.

Now, let's simply review some "facts" (as far as is known) from our two candidates first.

1. The Spinosaurus.

1.1 The "classical view".

In this section, let's go through the facts around Spinosaurus, as they were assumed to be correct, until 2014.
Let's call that "the classical view". This will be the subject of section 1.1.

However, recent finding changed the ideas on Spinosaurus quite dramatically. In which way, we will see in section 1.2.

Fig 1. Images of the "classical" Spinosaurus appearance.

As we might want to appreciate the environment (where the Spinosaurus lived) a bit more, maybe these two clips may help.
However, it must be stated that this series was developed while the "classical view" of Spinosaurus was still the current one.
As you will see, later data points to "another type of animal", or, at least, that new view applies to later generations of Spinosaurus.

From the BBC documentary "Dinosaur Planet":

1. Spinosaurus vs Carcharodontosaurus.
2. Spinosaurus fishes for prey.

Some more facts around Spinosaurus:

In the classical view, Spinosaurus was likely to be fisher, hunting anything it could trace in or around the water.
However, evidently, it was often roaming the landscape as well.

It lived in the "Cretaceous period", at about 112 to about 97 million years ago.

The first fossiles were found in 1912, in northern Africa (Egypt, Morocco).
Tall neural spines growing on the back of the animal, much resembled a "sail", but was possible used for heat regulation,
and/or communication to their fellow species.

All in all, not so many fossiles were found at all.

Paleontologist estimate that Spinosaurus have had the following properties and dimensions, as shown in the table below.
However, many estimates exists, which varies considerabely, due to various interpretations of the sizes of found skull fragments.

Some data about the classical interpretation (pre 2014) of Spinosaurus:

Period:	Early Cretaceous period, at about 112 to about 95 million years ago.
weight:	Likey to be from 7 to 9 tons. However, some higher estimates go around too, even up to 21 tons.
Length:	Likely to be around 50 feet / 15 m.
Bite force:	Might even be as high as 2 tons. Different studies show large variations.
Further characteristics:	Powerfull longer claws (forearms). Longer, smaller snout.

There exists indeed large variations in those figures. For example, for the weight, the estimates varies enormously.
So, it is save to assume a minimum of 7 - 9 tons for an adult animal.

1.2 The "new view" of Spinosaurus, as of 2014.

Actually, Spinosaurus was a truly amazing animal. Recent research (as recent as september 2014) shows that it likely had
swimming capabilities, and it might have lead a semi-aquatic life.

You might want to take a look the following popular articles:

nationalgeographic.com
nbcnews.com
bbc.com
smithsonianmag.com

In essence, studies on new fossiles (Morroco) seem to point to the facts that the skull was more adapted to a life in the water,
as well as that the hind legs were considerably shorter compared to the model of Spinosaurus in the classical view.
Mind you, the fossiles under study are likely from the period as far back as 95 million years ago.

A number of paleontologist find it to be a likely scenario, that, while time went on, Spinosaurus gradually "went back to the water".

So, in such a case, "the classical view" might thus apply to the "earlier" Spinosaurus, while the later generations progressively
adapted themselves more and more for a semi-aquatic life.
However, this view is not established yet as a consensus between the paleontologist.

It also seems that the new data supports the following dimensions for Spinosaurus:

Length: probably about 50 feet / 15 m.
Weight: probably at least 9 tons. However, higher estimates go around too.

It is estimated that Spinosaurus thus still is probably (somewhat) larger and heavier than T-rex.

So, where does this leave us now for the championship "Spinosaurus versus Tyrannosaurus Rex"?

In the classical view, Spinosaurus was a landanimal, only with a strong preference for water.
Maybe the very first sub species (the "classical ones", as in the period around 110 million years ago) could have been a serious match for T-Rex.

However, the later data supports the fact that (the later) Spinosaurus was adapted for the water, not unlike a present day crocodile is,
and while on the land, it's not that agile, and it's likely it could never win from T-rex.

But, it might be claimed that if a T-Rex was clumsy enough to accidentely slide off a hill (or something), and fell into deeper water,
(while still sound and at it's wits), the "new" Spinosaurus certainly had the best chance to be the winner.

So, all in all, it's probably fair to say that, on land, the score would be "T-Rex : Spinosaurus = 1 : 0".

Ofcourse, we all remember the fact that the "contest" is completely hypothetical, since the two species were seperated
by millions of years....

So, are we done yet? No way !

Let's next go through some details about T-Rex, and after that, move on to other candidates for the title of "most fearsome predator ever existed".
Who says we must confine ourselves to land animals or dinosaurs? We change this note on the fly.
So, for example, what to think of the immense "Megalodon"? I tell you, if you think that the White Shark is something, then just wait for Megalodon...
Among other candidates, we will see this pretty animal in section 3.

2. Tyrannosaurus Rex.

This animal does not need much introduction.

While Spinosaures walked (or swimmed) around from about 112 to about 95 million years ago, T-Rex lived in the period
from about 67 to 65 million years ago. That's indeed quite some time after the Spinosaurus era.

Although many fossiles were found (even almost complete specimens), still many facts around T-Rex are simply yet unknown.
For example, some say that it's quite likely that T-Rex was warm-blooded, which also would have large consequences
for the "performance" of the animal, and the frequency by which it needed to feed.
Also, some experts say that T-Rex was probably covered with feathers, what is suspected to true with more of the "later" dinosaurs.

Most fossiles were found in what is now North-America. However, some fossiles were found elsewhere too, and resembled those of T-Rex,
and some experts consider those animals to be related.

The T-Rex seems to be truly "build for the kill", if one views it's physical appearance. However, it's commonly accepted
by scientists, that T-Rex (like many other carnivorous animals) was not only a hunter, but partly a scavenger too.

Most impressive is it's "bite force" (which should be expressed in Newton, but often is done in pounds or tons).
Here different studies show large variations. But, it might even have been as much as it's own weight!

This enourmous "bite force" is probably only exceeded by the "Deinosuchus" (primordial crocodile) and "Megalodon" (extinct super Shark).
These extraordinary animals are discussed in section 3.

Some data about T-Rex:

Period:	Late Cretaceous period, at about 67 to about 65 million years ago.
weight:	Likey to be from 6 to 9 tons. However, some higher estimates go around too, even up to 18.5 tons.
Length:	Likely to be around 40 feet / 12 m.
Bite force:	Might even be as high as 7 tons. Different studies show large variations.
Further characteristics:	small claws (forearms), extremely powerfull hindlegs.

Here are a few common images of Tyrannosaurus Rex.

Fig 2. Some (public domain) images of Tyrannosaurus Rex.

3. Other candidates for the title.

This is just a fun note ofcourse. But..., I try to have the facts straight.

But new insights can change the game rather dramatically too. Just take a look at Spinosaurus.
From classical view, which basically means a land animal with a strong preference for fishing, the view changed
(as of 2014) to a swimming animal which does not seem to have a preference for land at all.
And, the posture changed considerably too, like it's not viewed like a "dino archetype" anymore with long hind limbs.
However, the "Spinosaures" remains a "monster carnivor" (figurally speaking), in weight, lenght, and bite force.

Now, it seems likely that T-Rex, in terms of raw power, was superior to Spinosaurus.

So, was T-Rex the most powerfull carnivor (predator) at all times?

No, in terms of raw power (weight, lenght, and bite force), it's very likely that "Megalodon" wins from both our dinosaurs.
Megalodon looks like a great White Shark, say a White Shark of 7m, and inflated by a factor 2 or 3.
This then would yield a Super White Shark of a length of 17m or 18m, or possibly even larger. As always, estimations vary largely.
Megalodon roamed the seas from about 28 million to about 1.5 million years ago.

Other candidates, notably "Sarcosuchus" and "Deinosuchus" (prehistoric alligator and prehistoric crocodile), were essentially "super crocs".
For example, if you would watch a large salt water crocodile, say 6m of lenght, and inflate it by a factor 2, you probably get
something which resembles "Deinosuchus".

First a warning: throughout scientific studies, the dimensions of those animals vary considerably, so it is somewhat dangerous
to create a suggestion of established fixed dimensions. This is not so.

However, a lenght of about 18m for "Megalodon" seems realistic, while "Sarcosuchus" and "Deinosuchus" might be in the range of 10,11m.

Now, in this section, especially the robustness, and "bite force" are key elements.

Now let's take a closer look!

3.1 Carcharodon Megalodon, the Super Shark.

Almost all people are familiar with dino's. However, I noticed that for quite a few people, an animal like Megalodon
was huge suprise! Such a "surprise", is no surprise to us. Indeed, what a formidable animal this was.
One should never speak of a "horrible" animal ofcourse (if one should carry that classification, it's probably man itself).

But, figurally speaking, with respect to "raw power" (weight, lenght, and bite force), it's absolutely phenominal.

Some data on "Carcharodon Megalodon":

Period:	From about 28 to about 1.5 million years ago.
weight:	Likey to be between 50 to 100 tons (100 tons for a 20m animal).
Length:	Likely to be between 14m to 20m. Different studies show quite some variations.
Bite force:	Likely to be somewhere in between 10 and 19 tons. Different studies show quite some variations.
Further characteristics:	A "White Shark-like" appearance.

Let's take a look at some (public domain) images of Megalodon.

Fig 3. Some images of "Megalodon".

Apart from the reconstructed "jaws", the images in figure 3, are likely to be a bit too "fancy". It's very possible
that Megalodon had an appearance that resembled the "Great White Shark", but some studies seem to point to a very bulgy front section
of the animal. If true, the length might indeed be more in the range of 14-16m, instead of some estimations of 20m or even longer.

Since this is a "fun note" (I want to stress that explicitly), we are especially interested (only) in raw power.
If you compare the length, weight, and bite force of the large carnivorous dinosaurs (T-Rex, Spinosaurus) to that of Megalodon, it's quite clear
who is our winner (for now).

You might like to view a documentary from National Geographic Channel (47 min).
If so, then use this link.