"Spinosaurus" versus "Tyrannosaurus Rex" versus "Megalodon" versus "Sarcosuchus" versus "Deinosuchus" versus "Livyatan" versus "Dunkleosteus" versus "Kronosaurus" versus "PredatorX" (funkei) versus "Mosasaurus".

This note is absolutely just for fun. It's only about top Predators, most notably, with respect to weight and bite force. I hope all details are ok.

1. 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. Hypothetically, such rival dino's 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.
   
2. 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).
3. 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.
   

1. Spinosaurus.

1.1 The "classical view".

In this section, let's go through the facts around Spinosaurus, as they were assumed to be correct, up to 2008-2014.
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 substantially. 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.

The above clips indeed illustrate the "classical view" of Spinosaurus.
If you like a "newer" intepretation (as of 2008-2014) of Spinosaurus, you might like this:

NOVA/National Geographic: Spinosaurus the aquatic dinosaurus (2014).

It's quite a long clip (53 min.), but it illustrates how this Dino eventually "returned to the water", which is quite a spectacular hypothesis.
But remember, in section 1.2, we also take a look at the "new" idea's on Spinosaurus.


Some more facts around the "classical" 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).
Tall neural spines growing on the back of the animal, much resembled a "sail", but was possibly used for heat regulation,
and/or communication to their fellow species, or other sort of signalling function.

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 ranging from 7 to 9 tons.
Length:	Likely to be around 50 feet / 15 m.
Bite force:	Might even be as high as 2 or 3 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 2008-2014.

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.

However, it must be said that not all scientists are in full agreement with this new ideas on Spinosaurus.
While browing throug articles, I was surprised to see that some experts seem to be a bit in doubt about the methods used,
how the "new animal" was reconstructed, from this newer data.

Or, possibly, there were 2 different species, one more like classical one, and one according to the new data.

As another line of reasoning: from the limited number of publications I could find, it seems that a few paleontologist find it
to be a likely/possible 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, with, for example, the more massive hind limbs,
while the later generations progressively adapted themselves more and more for a semi-aquatic life.
However, this view is certainly not established yet as a consensus between the paleontologist.

Fig 1.2. Images of the "newer" Spinosaurus appearance.



So, the Spinosaurus "file" is not closed yet, and let us hope that new future findings will bring more clarity.

Anyway, the older and the new data, both support the following dimensions for Spinosaurus:

Length: likely to be about 50 feet / 15 m.
Weight: likely to be at least 9 tons. However, somewhat 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 at all, 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....

By the way, if you are a fan of Spinosaurus, here is a nice image of the "classical view".

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?
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 "Deinosuchus" (primordial crocodile), "Megalodon" (extinct super Shark),
and a few others like "Livyatan" (a prehistoric tooth whale), and "Kronosaurus" & "Predator X" (pliosaurs, or swimming reptiles).
These extraordinary animals are discussed in later sections.

Some data about T-Rex:

Period:	Late Cretaceous period, at about 67 to about 65 million years ago.
weight:	Likey to be in the range from 6 to 8 tons.
Length:	Likely to be around 40 feet / 12 m.
Bite force:	Might even be as high as 5 to 7 tons. Different studies show large variations.
Further characteristics:	small claws (forearms), extremely powerfull hindlegs. Possibly warm-blooded animal, with high performance.

Here are a few common images of Tyrannosaurus Rex.


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

3. Carcharodon Megalodon.

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".

And other enormous predators could be found in the seas, like Kronosaurus, or Predator X, or Mosasaurus, to name a few.
We will see those in later sections.


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 at Megalodon!

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.
Suppose we have a 70 tons Megalodon. That's ten times (!) the weight of a T-Rex. Also, check the tables above. The bite force of Megalodon,
is actually comparable to large high-power industrial machines, like those found in mining industries.
In fact, it's not unfair to say that T-Rex would have been no more than just a "snack" for Megalodon.

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

Now, do we have found our Winner? Before we hand out the price, let's still wait a bit until we have seen
a few other candidates, like the Super "croc-likes", and ofcourse the Killer Whale "Livyatan", and the pliosaurs "Kronosaurus" and.... "Predator X".

4. "Sarcosuchus Imperator", a Super "croc-like".

In our present time, some awesome and large carnivors/predators exists, like for example the Grizzly, Kodiak bear, Polar bear, tiger, and the Lion, to name a few.
Again, here we solely use the angle of weight and bite force of individual animals. Using other criteria, such listing might change quickly.

Seen from the perspective of an optimal combination of "weight and bite force", the Siberian Tiger would score very high.
One of the largest Siberian Tigers (not the Indian or Bengal one) ever measured, was about 465 kg. One of the largest male Lions was found to be about 313 kg.
Although, on average, the weights are considerably less than those figures above, it gives us a clue on how "to scale" those two predators.
Indeed, I myself have have always found the Siberian Tiger to be the real champion of all cat's. Mind you, some say the Bengal is actual more powerfull.
There is really no doubt that a healthy adult Tiger usually wins from a healthy adult Lion.
It's a bit of a silly comparison ofcourse. Fortunately, such fight "in the wild" is hypothetical.

For my favourite cat, it's horrible indeed that only a handfull of specimens of the Siberian Tiger are left, mostly due to this awfull poaching.

Now, what about the Jaguar? It's a predator indeed, and it is often claimed to have the highest bite force of all felines.
Although it's bite force is awesome, the "weight/bite force" combination makes it reside (somewhat) lower on the list of felines.

Now, the "large" bears, the Lion, the Tiger, and even the Great White, are not on top of the list of animals with the optimum "weight and bite force".
Again, we are only considering carnivorous animals (predators), so for example a Hippo is not on the list (althoug it's bite force calls for an ethousiastic Wow!)
No..., it's a full grown adult "saltwater crocodile" or possibly a "Nile crocodile", which takes the pole position.

Well, is that really true?
The largest of the toothed whales and the largest current toothed predator at all, is the Sperm Whale. It can grow to about 16m of lenght,
and fully grown, it weights about 40-50 tons. The lower jaw might have large teeth, although also specimens have found with only rudimentary teeth.
This animal should be considered to be on our list too, and maybe it's the real #1. However, to my knowledge, there exists no estimates on it's biteforce.
However, intuitively, you might say this: the present day #1 is the Sperm whale.


Since the present day top crocodiles, are "top", or score very high on the list, it surely makes sense to take a look at pre-historic specimens.
Indeed, we will be completely amazed by two "croc-like" animals namely "Sarcosuchus" and "Deinosuchus".
In this section, we will try to appreciate "Sarcosuchus Imperator". In section 5, we go for "Deinosuchus".


Scientists are serious, when they estimate an adult Sarcosucus to have had a lenght of about 11, 12 meters, and a weight of around 8 tons!
Now, compare that with T-Rex, which is usually estimated to be around 7 tons.

In apperance, Sarcosuchus was "crocodile like", but can hardly be seen as relative of our familiar crocodiles.
Sarcosuchus wasn't actually really a crocodile, but rather a type of reptile known as a "pholidosaur."
Another "Super Croc", namely "Deinosuchus", is truly a distant relative of our modern crocodiles and alligators.

Characteristic is it's long snout, with teeth specialized for catching fish (and anything else that came close).
With respect to sheer length, it is assumed to have been the largest "croc-like" animal.

It's estimated to have lived as from about 112 to about 90 millions of years ago. So, here too (as with Spinosaurus),
it could never have met T-Rex, since T-Rex walked around from about 67 to 65 million years ago.

Theoretically, it could indeed have met Spinosaurus. I believe that there exists no clue that such an event ever took place.
It's likely that their habitats were quite geographically seperated. However, it cannot be excluded.

Some data on "Sarcosuchus Imperator":

Period:	From about 112 to about 90 millions of years ago.
weight:	Likey to be around 8 tons.
Length:	Likely to be around 11, 12 meters.
Bite force:	Often estimated to be around 5 to 6 tons.
Further characteristics:	A "crocodile-like" appearance, but not a true relative.

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

Fig 4. Some images of "Sarcosuchus".



Suppose a confrontation happened between both an adult and healthy Spinosaurus, and Sarcosuchus. There is no way to say who
would be the winner. It's more likely they would have created space between them, and further ignore each other.
But who knows? Maybe terrible fights did indeed took place.
It's also a fact that present day crocs are very tough. But Sarcosuchus was not a true croc. And Spinosaurus is no pussy.

Now, since we are speculating a lot in this "fun" note, let's suppose a confrontation happened between T-Rex and Sarcosuchus.
That's completely nonsense ofcourse, since both animals were seperated by millions of years in time. But let us just suppose...
That would be something! Now, if T-Rex was indeed a warmblooded animal, it would have had an enourmous endurance (and appetite).

It seems that we don't know much about Sarcosuchus hunting patterns. It does not seem likely, that it "lurked"
in the deep, near the shore of a pond or river, and just waited for animals to come for a drink.
If any smaller animal did, would it then explode from the deep, and went for the neck for an unescapable grip, like many
present day crocs do? Or the most urgent question is: would it be capable of performing a "Death Roll"?
Scientists don't think that a "Death Roll" was in it's strategies. You see the long small snout?
It's just not likely, at least not with heavy prey. By the way: when became the "Death Roll" part of the genetic imprinted
instinctive memory? Unfortunately, I could not find such data yet.

To me Sarcosuchus physical appearance, just seems to have the "looks" of a fisher in ponds, swamps, and rivers.
It's teeth and longer snout, seems to be more equiped for fast operations in the water itself.

However, the estimated bite-force is again enormous: estimated to be 6 to 8 tons. Together with the weight of the animal,
would make it an absolute awesome adversary for any other predator.
It's not unlikely, that it had smaller Dino's, especially those near swamps, ponds etc.., for lunch.

So how about "Sarcosuchus versus T-Rex"? It's speculations "all over the place" here, but I really can't see any reason
why T-Rex would have lost such battle. I would place the bet on T-Rex.
Since this question is unrealistic anyway (both animals lived millions apart in time), we may gamble and guess as we like.

If the animals would not avoid each other (or ignore each other), I would say that the massive, and quick T-Rex,
would go for a fast, surprise, Monster bite "out of the blue".
And possibly, if the croc-like spotted T-Rex first, it might go off, and be headed for deeper water quickly.

Other heavy-weight "croc-likes" were out there in history. One of them is "Deinosuchus", not with a long small snout,
but this time, we see a croc-like with an alligator shaped, broad (U shaped) beak. It's widely regarded as a true distant relative
of our present day crocs/alligators. Let's see what turns up with this Super croc.

5. Deinosuchus, the "Terror Croc".

When I browse through the information on the Super "croc-likes", it seems that Sarcosuchus (see section 4) is often viewed by many as the
most fearsome "croc-like". For me, it's different. After that tiny bit of research that I did up to now, it became clear to me that it's
actually Deinosuchus which is likely to be the most powerfull croc-like. Well croc-like? It is really a remote relative of our present day alligators.
Deinosuchus seems much more rugged and massive. It's likely to have had the "pantser" like modern crocs have, and it's massive boney jaws
impress (at least) me, much more than Sarcosuchus did.

It seems unclear if Deinosuchus was capable of doing a "Death Roll". It seems from the "more serious literature", that this tactic
among crocs emerged only at a much later time. So, probably not.

Could either of them have faced our super dino's, that is, Spinosaurus or T-Rex?

- Sarcosuchus:
is estimated to have lived as from about 112 to about 90 millions of years ago. Thereby it was probably a "contemporary" of Spinosaurus.

- Deinosuchus:
is estimated to have lived as from about 80 to about 70 million years ago. Thereby it was NOT a "contemporary" of Spinosaurus.
Also, what we call T-Rex, walked around from about 67 to about 65 million years ago. So, actually, Deinosuchus was NOT a "contemporary" of T-Rex either.

So, T-Rex could never have had any problems with those crocs (but possibly..., it did with other super-crocs).
But, Spinosaurus might have some occasional quarries with Sarcosuchus, unless their habitats did not overlap, which seems to be the case.

The following clip is a bit "too much sensational", therefore I was not sure at all to place a link in my note. However, this note too, is completely
unscientific, and actually is no more than a quite silly search of "raw power", which is a ridiculus idea ofcourse ;-) .
However, honestly, I like it, and possibly others too. So, here is that "silly link". It tries to compare our two supercrocs, which fails, I think.
But what is actually nice, is that it might convey a proper feeling of dimensions and apperance of those crocs.

Sarcosuchus vs Deinosuchus

Some data on "Deinosuchus":

Period:	From about 80 to about 70 millions of years ago.
weight:	Likey to be around 8 tons.
Length:	Likely to be around 10, 11 meters.
Bite force:	Often estimated to be well over 10 tons. Different studies show quite some variations.
Further characteristics:	A "crocodile-like" appearance, and indeed a distant relative.

Fig 5. Some images of "Deinosuchus".



Now, what happens in a hypothetical clash between T-Rex and Deinosuchus?

When we compared Sarcosuchus with T-Rex, I personally did not give Sarcosuchus much chance: T-rex simply seemed to be the better "gladiator".
However, this time, things seems to be bit different! First, Deinosuchus weights about the same as T-Rex, and it's probably
heavily armoured. That makes a real difference. Last but not least, it's bite-force is absolutely awesome. It's generally quite a bit higher compared
to that of T-Rex, since the absolute max of T-Rex is estimated to be 5-7 tons.
It's not only the sheer power of the bite. If Deinosuchus could display a fast reaction as we see with the present day crocs, and if it
indeed had such tough armour as quite some paleontologist supposed it had, then it might have been an equally powerful adversary.
Ofcourse, we can't say anything truly substantial about which was "the Boss". Therefore, I would propose to say: "T-Rex vs Deinosuchus: Unknown".

Now, next we pay attention to our last three contestants. One is a killer Whale, one is fish with a "wire cutter", and the last one is a Pliosaurus.
The latter is often called "Predator X". Indeed, there was a time that this animal was known to exist, but most relevant details were shrouded in mystery.
But first..., the Killer Whale "Livyatan melvillei".

Tip: more on Super crocs.
Although Deinosuchus and Sarcosuchus are the best representatives of super crocs,
there existed a few other long, heavy "monster" croc-likes. For example "Rhamphosuchus", and "Purussaurus".
If you are interested in pure raw power (weight, bite-force), especially "Purussaurus" is promising. Maybe it's nice to do web search on that one?

6. Livyatan melvillei.

This time, we are talking about a "mammal", or indeed, a whale actually.

The animal is a very old relative of our present day "sperm whale". Notice, that Livyatan had enormous teeth in both
upper and lower jaws, in the order of 36 cm of length! No doubt that Livyatan was a formidable Predator.
A reconstructed skull can be seen in the "Rotterdam Natural History Museum".

Fossiles were only found as recently as 2008! Therefore, much study have still to be done on this incredable animal.
Some high-level details are the following:

It's estmated to have live around 12 million years ago. The length of a healthy adult should be somewhere in the range
of 13 to 17 meters. It is likely that it had the same sort of oil and wax reservoirs as sperm whale have, and therefore
it is assumed that it was able to dive into large depths too.
It's weight should have been around 25 - 50 tons.

Some basic facts of Livyatan melvillei:

Period:	Estimated to have lived about 12 million years ago.
weight:	Likey to be in the range from 25 to 50 tons.
Length:	Likely to be around 50 feet / 15 m.
Bite force:	Have not found solid estimates. Likely to be extremely high.
Further characteristics:	Very large teeth in upper- and lower jaws. Physical appearance probably not unlike the Sperm whale.

Fig 6. Some images of "Livyatan".



I have not found reliable estimates on it's "bite-force", yet. You don't have to have much imagination, to understand
that Livyatan's bite-force was incredably high. Maybe even higher as Megalodon.
In figure 6 above, you can find some pictures of it's jaw. Nature would not have produced such jaws, without a correspondingly
large "bite-force". So, even in the absense of scientific estimates, we know that it just got to be very, very, high.

Interestingly, it was a contempory of Megalodon. Suppose that their habitats also have overlapped.
What would have happened in a hypothetical clash between Livyatan and Megalodon?

No one can answer that. But if Livyatan was not solitary but instead hunted in "packs", nothing would have been a match.
In a solitary (one to one) confrontation, I am not sure. However, the "specs"of Megalodon seems to be slightly more impressive.
However, was "Livyatan", for example, so intelligent as our present day whales? If so, this scenario might have had an additional dimension.

As is true in all "battles", the side with the "best information" has a huge advantage over the opponent. It's very likely that both possesed
sharp sensory systems. It's likely that Megalodon depends mostly on detection of vibrations of movements, and smell.
However, it's very likely that Livyatan could deploy it's sensitive sonar system, just like our present day tooth wales have.
It's very speculative ofcourse, but Livyatan might have detected Megalodon way before Megalodon would have detected Livyatan.
That would give rise to much more interesting speculations..., which I better not elaborate on...

7. Dunkleosteus terelli.

This is our oldest contestant for the title. It's a "fish", and lived about 380 millions of years ago.
Dunkleosteus was likely to be the dominant predator of its time.

It was "toothless". Now, before you start laughing, take notice of this: Instead of teeth, large "zig-zag" boney plates in front of the mouth,
acted as a sort of "wire cutter".
It is believed that the mechanism was incredably effective. You might take a look at figure 7 below. Note the reconstruced skull.

The fish had boney armour at the skull, and that armour was repeated up to a short distance behind the skull.
Some skulls have a lenghth of about 1 meter. Since only parts of the skull were found, estimates on it's lenght and weight vary somewhat.
Some estimations go up to 10m of lenght, so it seams pretty save to assume that it was at least 8m long.


Fig 7. Some images of "Dunkleosteus terelli".



Some basic facts of Dunkleosteus terelli:

Period:	Estimated to have lived about 380 millions of years ago.
weight:	Likey to be a maximum of 4 tons.
Length:	The maximum estimates even go up to 10 m.
Bite force:	Often estimated to be in the order of 2 - 4 tons. A few scientists believe that it is actually considerably higher.
Noteworthy remark:	Many people find the appearance of "the dunk" very frightening.

On the Internet, you can find great illustrations of "Dunkleosteus terelli". However, I can only use Public domain images, or images which fall
under "fair use" policies. Some protected images for example, nicely illustrates the mechanics of Dunkleosteus's jaw. That's a very remarkable
construction indeed. Basically, the jaw used 4 hinges (2 on each side of the skull), where 2 were lokated at higher place on the skull, and 2 at a lower place.
It operated in such a way, that the animal could open and close it's jaw with an immense speed. Such a process is believed to be completed
in such a small timeframe as even 50 milli seconds. That's really fast.

The presently known "weight and bite-force" of the animal, does not make it a winner of our contest. We already have seen more superior animals
(for example Livyatan melvillei), in that respect.

However, there are (in my view anyway) some uncertainties with "the dunk". First, if the maximum weight- and lenght estimates are indeed
as high as is believed today, it might well be the the bite-force (now estimated to be max 4 ton), will be corrected in the positive direction.
However, there are no direct signs that such scientific "corrections" are going to take place, yet.

So, there are more powerfull Predators that roamed the seas in the past. Still, even with the data as presented above "the dunk" had an impressive "performance",
and an awesome appearance. Thus, it simply had to be incorperated in this listing.

Next, our last contestants: the "top" Pliosaurs "Kronosaurus" and "Pliosaurus funkei".

8. Kronosaurus and Pliosaurus funkei (Predator X).

"Pliosaurus funkei" is a large and powerful animal for sure. However, scientists now believe that the animal was, initially,
substantially "oversized". That's often attributed to a too large addition of dorsal vertebrae.
The initial sizing is now corrected, and is now believed to be in the order of about a maximum of 12, possibly 13 meters.
That's still very impressive for a Predator.

The large "familiy" of Pliosaurs, had at least two very large members. One of them is "Kronosaurus", and the other one was originally
dubbed "Predator X". That one was later classified as what we now know to be "Pliosaurus funkei".
Both species were short necked and had four large flippers. Althoug "Pliosaurus funkei" is the real Predator X, I like to mention
Kronosaurus as well, since Kronosaurus scores high too, on the "scale of awesomeness".

But it must be understood that more members of the Pliosaurs family were very large predators, like for example "Pliosaurus rossicus".
Others, like the "Liopleurodon", had a lenght somewhere in the 6.5 m range, and was thus considerably smaller than our two top predators.

Another family is that of the Plesiosaurs. They are characterized by their long necks, four large flippers too, and this family
had quite a variety of differently sized members. And some were pretty large as well. But the remarkable long neck sets them apart from the Pliosaurs.
However, the exact classification of found fossiles has proved to be no simple task, since the Plesiosaurs probably had short-necked members too.

Back to our two Pliosaurs. Kronosaurus is believed to have reached a maximum length of 10, 11 meters. Pliosaurus funkei was even
somewhat larger, having a maximum length of up to 12, maybe 13 meters. Both were equiped with formidable jaws, with teeth even up to 30cm.
However, a considerable number of studies have been performed on both animals, and serious estimates (on weight and lenght) still vary.
Indeed, some argue that valuable data is still missing, especially with respect to Pliosaurus funkei. Kronosaurus seems to be more complete.

Fig 8. Some images of "Kronosaurus" and "Pliosaurus funkei".



Here is some data, on which most paleontologists would agree on:

Some data on "Pliosaurus funkei":

Period:	Approximately 145 to 150 million years ago.
weight:	Possibly up to 10 or even 15 tons. Rather uncertain really.
Length:	Likely to be around 11 to 13 meters.
Bite force:	Very high. No true consensus seems to exists. Possibly a few times that of T-Rex.
Further characteristics:	The front flippers, are somewhat larger than other pliosaurs.

Some data on "Kronosaurus":

Period:	Approximately 110 million years ago.
weight:	Possibly up to 7 or 9 tons. Some claim that it is considerably more.
Length:	Likely to be around 9 to 11 meters.
Bite force:	Very high. No true consensus exists. Likely to be a little lower than funkei's.

Following is a clip from "Planet Dinosaur, BBC about funkei. However, the clip is from about 10 years back. Presently, consensus exists
between scientists that the size of funkei was somewhat "oversized" at that time. Instead of 15+ meters, Predator X (or funkei) is now believed
to have a lenght in the order of 12, 13 meters. If you like to see it, you can use this link.

It's clear that both "Kronosaurus" and "Pliosaurus funkei" were awesome predators. Funkei's estimated bite force, was indeed very large.
I have seen estimations of around 4 times T-Rex's bite force. Well, if an animal can reach a bit force near
it's own weight, that's already amazing. Could 4 x really be realistic? I have some reservations, unless the
animal's jaw muscles indeed were strongly developed.

As said before, uncertainties still exists as to the lenght, weight and other characteristics of funkei.

9. Mosasaurus (Hainosaurus).

Actually, "mosasaurs" is a familyname for a large scala of different members, for example, with respect to the maximum size.

I started out having some "reservations" on Mosasaurus. Although it's length is impressive, the somewhat longer and slim tail,
made the animal look somewhat "less powerfull", for example, compared to the massive Funkei (see section 8).
However, we should just stick to the data which interests us most, which is "length/weigth/bite-force".

The largest mosasaurus might have been "Hainosaurus". It seems that most scientists support that fact.
However, not all articles specifically refer to "Hainosaurus" when talking about the largest specimens. Other names go around too.
For example "Tylosaurus", and a member, which indeed lived under the present day name "Mosasaurus".

Thus indeed, the name "Mosasaurus" (or "Giant Mosasaurus") is reserved for (one of) the largest member of the family.

At first the Animal was estimated to have a max length of about 17m. Later, this was downsized to a somewhat smaller scale.
That is ofcourse all related on how to reconstruct the animal, on what is available from fossile remnants.
It's generally speaking, a very tough job. The best estimates on the maximum size of the largest mosasaurus today, is about 13 meters.
The strange thing is, that a few musea have skeletons which are quite a bit longer. Maybe these reconstructions are flawed too.
Another thing is that some scientists keep on talking about max. sizes, which are of well over 15m, and even still up to 17 or 18 meters.

Note:
We have seen that "downsizing" also has occurred with Kronosaurus en "X" (see section 8).

All in all, I would say that even up to very this day, there exists quite some uncertainties around the dimensions
of the largest specimens of the Mosasaurs family (Hainosaurus, Mosasaurus).

The maximum weight of a Hainosaurus or Mosasaurus of an animal of 17 meters, is estimated to be 20 tons.
This is quite a bit more than present day estimates of the weights of Kronosaurus, or Funkei.
However, Funkei too, had an attributed lenght that started out at 15+ meters. Nowadays, most scientists believe that it is
more likely to be around a maximum of 13 meters.

This means that a more realistic weight should then be somewhat below 15 tons, for a 13m long "Mosasaurus".

What about it's biteforce? I have not found any consensus with respect to it's biteforce. It could nevertheless be very high.

Some data on "Giant Mosasaurus":

Period:	Many say 85 to 65 million years ago. Other estimates speak of 70 to 66 million years ago
weight:	Possibly up to 15 tons. If the former, original estimates hold: 20 tons or somewhat higher.
Length:	Likely to be around 13 meters. If the former, original estimates holds: up to 17, 18 meters.
Bite force:	Could not find any consensus. Likely to be the same as Funkei's (see section 8) or possibly a little lower.

Fig 7. Some images of "Mosasaurus".



Although Mosasaurus is a very impressive animal, I believe it ranks somewhere in the same class as Pliosaurus Funkei.
It would be very difficult to point to a "winner", based on the currently available data.
However, it seems to me (and that's personal), that the more massive Funkei sits quite bit higher on the ladder.
One weak basis for that claim, would be the lenght of the Funkei's teeth, which is around 30cm. The teeth of Mosasaurus are smaller.

Obviously, if the estimated maximum length for either Funkei, or Mosasaurus, would (again) be corrected, and this time to a longer value
the picture would change quickly.

10. So, Which Is #1 ?????

Ofcourse, there existed larger animals than those shown in this note. However, this note was entirely
focussed on Predators...

So, what do you think? Was perhaps a giant predator missing in this note? Well, actually there were a lot missing. For example,
the "famility tree" where T-Rex belongs to, is quite wide. And as another example, there were indeed a few more Super crocs.

And, maybe, somebody thinks that "Ginanotosaurus" was missing... I was indeed strongly tempted to include Ginanotosaurus here.
Ginanotosaurus was more or less equal in size as T-Rex, however, I came accross to later scientific findings, suggesting that it's bite force would have been
considerably less compared to T-Rex (sometimes even estimated to be two to three times less).
So, that's why I left out Ginanotosaurus, since T-Rex just seems to be a better representative.

Still missing other gigantic Predators...?
That's only obvious!
Think of All those millions of years, and that enormous variety of predators...., and then some nerd like "Albert" would create the perfect list? No way !!!
Also: A note like this, is never finished, and I will add "Champions" when I come across them.

As another thing... It might also be argued, that smaller agile predators, but which operated in packs, were truly the most fearsome animals.
But, this fun note is only about individual "raw power". Indeed, taken other criteria into account, like social coherence, intelligence,
aggression, attack strategies, attacks in "packs", advanced sensory (like sonar) etc.., the list would probably change quickly!

Although this note is primarily meant for "fun reading", I tell you (or I hope to convince you), that I tried to have the facts straight.
If that worked..., I don't know really. It has amazed me, how much the numbers and estimations have varied along all the relevant articles.
Indeed, for many animals, a large number of scientists argue that valuable data is still missing. More data could
seriously change the current views. And who knows what still waiting to be found?


Now, Which Is #1 ?

There is not a quick and definitive answer to this question. As an attempt to do so...:

Among many other folks..., I think too it is "Carcharodon Megalodon".
Or is it actually "Livyatan"? Or...possibly "Predator X"?
Well, "Funkei" seems to be somewhat more powerfull than "Mosasaurus". "Livyatan" in turn, seems to be more powerfull than "Funkei".
And Megalodon seems to be a bit more impressive than "Livyatan". So, there it is.

As another type of #1..., if you would like to know which one my favourite is...
That would probably be that strange alien/duck like "Spinosaurus".

11. Later addition: Some Top predators which were not in my top 9.

Addition on 19 Februari 2015

Ok, it's a bit of a silly note, if one explicitly selects prehistoric predators solely on the basis of "lenght, weight, and biteforce"...
But I am pretty sure that for a lot of others, those are very important properties too, especially if the reader's
age is in the range 6 - 12 years old. That's an important group !

The last few months I came across some fantastic animals, which were not in my personal list as shown above.
Still, I have found no compelling reason to change any of the 9 candidates above.
However, in a few occasions, I was tempted to actually change the list, but ultimately, just not enough to do so.
I simply did not found any better one, in terms of "lenght, weight, and biteforce".

But.., I really want you to know about the Champions below, because, simply... they are great !
Therefore, I like to present some very tiny notes about them.
So this note is far from being static. I will add "strong animals" when I find them !

Secondly, on the Internet, you can find many talks about the "No 1" prehistoric predator, and sometimes, "candidates"
are suggested, but which probably "are not it". Ofcourse, views varies among people.
For example, "Baryonyx", is a fantastic dino. It looks like a smaller Spinosaurus (except for the "sail"), but it only
weights about 2 - 2.5 tons, and is about 2.5 m tall (and 9 m of length).
As it lived way long before T Rex, they could never have met. However, hypothetically, it would have been no match for T Rex, really.

1. Baryonyx:

Remains were first found in England, and later, in other places in Europe, Africa.
It's an early relative of Spinosaurus (tree of the "Spinosauridae"), and lived about 130–125 million years ago,
which is quite some time before Spinosaurus.

Relatively speaking, it was not that large (e.g. compared to Spinosaurus, or T Rex).
Take a look at this:

Lenght: about 9m
Height: about 2.5m tall
Weight: about 2.5 tons.
Biteforce: not large compared to e.g. Spinosaurus, or T Rex
Clawforce: very high.

Now, compare that to the data of Spinosaurus (classical and new) in chapter 1.

What makes Baryonyx really special (in my view). are it's gigantic claws, and long arms. Except for the spines, it really
is a Spinosaurus "look-a-like", at least for the classical view of Spinosaurus.

Indeed, Baryonyx means "Heavy Claw", which is a strikingly good name for this fantastic animal.

Fig 10. Baryonyx.



Baryonyx is assumed to have been a fish eater, and it is strongly suspected that it scooped it's prey out of the water,
using it's large claws.

A larger relative (but still way smaller than Spinosaurus) is "Suchomimus".
Maybe you like to do a websearch on that one?

Since both are way less powerfull than Spinosaurus (or T Rex, or one of the others), they were not in my top 9.

However, if you haven't seen a reconstruction of Baryonyx yet, I am sure you will be immensly impressed too (like I was).

2. Allosaurus and Carcharodontosaurus:

3. Giganotosaurus:

That's it. Hope you liked it !

Remark:

Ofcourse, every note that I produce, is free for use, anyway you like it.
But especially this one, might be great as a basis for a schoolproject of a kid.
If you want to do so, then read it carefully, check the data with other sources, and there you go...!