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White Rhinoceros v Allosaurus fragilis
May 15 2012, 06:41 PM
would it be possible for a big enough allosaur to headbutt a rhino hard enough to make it fall to the ground? if so wouldn't that be the end of the battle the allo would go in for the final bite(s) and kill the rhino? would it be possible? sorry if i sound like an absolute idiot
I don´t know if Allosaurus skull would be solid enough...
Imo a really large specimen likely would be capable of knocking even the largest rhino over, but I think it would be bettet to jump at the herbivore like it could have done with Sauropods.

Gastornis v Achillobator
May 14 2012, 09:40 PM
It really depends on where they're fighting, if it's open, I'd say the dromaeosaur would win very often, but if it has to stay in front of the bird, it's dead.
I also agree. In frontal combat the Gastornis is superior to the dromaeosaur because of it´s much stronger bite.
The Achillobators claws aren´t made to kill an opponent in front of the animal, and The dromaeosaurs skull is no killing weapon.
Also, gastornis likely could move more freely in dense vegetation because of its Shorter and Stouter built.

But in the open, Achillobator would´ve had the superior speed, agility and grabbling ability, as well as deathly claws.

Leopard Seal v Bull Shark
May 14 2012, 12:04 AM

One bite to the neck or head would crush the seal's skull or back
Shark´s teeth do not crush, they slice.

The Shark seems to be more in it´s element, but leopard seals certainly are fast and maneuverable, and they have a nice Size advantage.
The shark´s jaws look like they were more efficient in inflicting large wounds on large animals, but I favor the seal at maximum weight.
At parity I think the Shark would win, due to it´s more effective jaws.

A size comparison would be good.

White Rhinoceros v Allosaurus fragilis
May 14 2012, 12:46 PM
May 14 2012, 08:19 AM
"rhinos get killed by predators substantially smaller then a Allosaurus"

Such as?
Not a white rhino, but tigers have been known to kill Indian rhinos by themselves on very rare occasions.
Are there any photos/videos to confirm this claim? I can´t imagine a single tiger killing the second largest rhino in the world. When a pack of Lions doesn´t dare too attack a white rhino, then a Tiger certainly wouldn´t try it with an indian rhino.

A 12m allosaurus would probably be about 4t in weight, what is already much heavier than a normal Rhino. Rhinos only grow larger than 3000kg on very rare occasions, and then they are overweight and much too sluggish to fight.

I would favour the Rhino against a smaller A. fragilis specimen due to it´s weight advantage, but when the Allo is larger than 10m, it would have enough power to easily kill the Rhino by biting it into the belly. For a smaller specimen, it wouldn´t be that easy to kill the rhinoceros, because of its girth. But an Allosaurus is a far more formidable predator than any Tiger or Bear, due to the mere fact, that it´s skull is that much larger. It would be able to injure it´s opponent with relative ease compared to most modern predators.

Also, the largest estimates put A./Saurophaganax maximus at 15m.

Megalodon size
The models all look accurate.
I just wonder why there are more and proportionally smaller teeth in the largest Meg reconstruction than in the jaw of a great white, while the opposite should be the case.
The last two linked jaw reconstructions seem better to me as the teeth look larger compared to the overall size.

Hardest bite force of any vertebrate
Sorry for intervening, but this doesn´t belong here, so stop annoying Grey! I don´t have any idea what you´re talking about, but write it into a PM!

Visual Comparisons Thread
Imagine getting hit by one of those paws!

Posted Image
Giganotosaurus here is 16m.
EDIT: Sorry for that bullshit I wrote, 16m is complete exageration, tough I still think with such a huge skull and all of the tail unknown it likely reached more than the official lenght estimates. So donj´t take that figure seriously, I wrote it when I wasn´t very well informed. Maybe 15m could be, like it can be seen in Prehistoric Cat´s comparison that was posted later on this tread.

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Skull comparison of Phorusrhacos, Kelenken and Procariama (not to scale)
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known remains of Dracovenator
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skull reconstruktion of Coahuilaceratops

White Rhinoceros v Allosaurus fragilis
At parity I think the Rhino would win, but a 12m Allosaurus could easily inflict fatal injury on the mammal by using it´s head like an axe.
Allosaurus probably also was agile enough to dodge the rhinos attacks.

Iguanodon v Baryonyx
I think a 10m iguanodon would have weighed more than 3t.
Imo iguanodon would win because of it´s size and strenght advantage.

Daeodon shoshonensis v Utahraptor ostrommaysorum
I think Daeodon would win, because of it´s weight advantage (if we use a 7m Utahraptor) and its compakt built.

Maybe Utahraptor could outmaneuver it´s opponent and then wound it fatally, but I think the Pig could turn fast enough to defend itself.
6/10 for Daeodon

Megalodon size
Then I probably used an inaccurate picture of a great whites´ jaws to compare it.

Megalodon size
I just compared the megalodon jaw reconstruction to the jaw of a great whit shark.
The teeth in the Meg jaw seem to be a good deal smaller at parity compared to the ones of a great white, shouldn´t they be larger?

Hardest bite force of any vertebrate
May 13 2012, 02:52 AM
The 17 metre estimate by henry was based on a vertebra that could have been a caudal vertebra of a cetiosaur. I think occams razor suggests the latter.
Is it conclusively the vertebra of a sauropod or could it be that it belongs to a pliosaur? As much as I know there have been controversies about it, and the BBC-pliosaur was based on it.
But is there sureness that it wasn´t a pliosaurs´ vertebra?

The most dangerous extinct predators to Man ?
May 13 2012, 03:00 AM
Scientists are apparently confident into the new 9 tons estimate for Sue. But they say it may be applied to other predatory species as well.

T-Rex was thus likely heavier but same for Carcharodontosaurids and others.

However, as for the size discuss, don't forget that even for T-Rex there are possibilities of larger individuals than the officially larger Sue.

That's not the point here though. Allosaurs would be more dangerous to humans than Rex because of their physiology and lifestyle.
But there are far more t rex specimens known than e.g. Saurophaganax or giganotosaurus. And even the few specimens we know of these theropods are at least as large as the largest of the numerous Tyrannosaurus skeletons.
So when there is the possibility of larger individuals in T rex (and every claim, even from scientists has to be treated carefully, because there is so much exageration concerning t rex), there certainly is a possibility of larger individuals in other, less well known genera.
I just don´t think a Tyrannosaurus that bulky is realistic, and there seem to be scientists that have the same opinion.

I couldn´t find any scientific evidence for tyrannosaurs larger than Sue (there are rumors of so called C rex and t. imperator), maybe I´m not searching in the right place, but i think tose are just rumors made up by T rex-fans.

Sorry for wandering off the topic, I just wanted to define my position about this. Is there a tread about giant theropods? Then we could discuss it there.

I can´t imagine something similar in built to t rex trying to chase down a human. It isn´t even clear if it would have been fast enough, and its jaw and overall anatomy seems to be designed to attack well armed herbivores roughly its own size. Killing a Human would probably cost it too much energy to be profitable.

What about Argentavis? A bird with an 8m wingspan and the weight of a human could have been an enourmous hazard to human beings if they had coexisted.
Or Entelodonts? They are oftren depicted as being very agressive (though I don´t know how much scientific evidence there is for such a behaviour).
Hyaenodonts or Amphicyonids?

And I still think a Human would be the perfect prey for Utahraptor. Enough nutritional value and it couldn´t really fight back...
Megalania (sorry, I mean varanus priscus)? Batrachotomus?

Hardest bite force of any vertebrate
(page 39, 2nd collumn, 3rd paragraph)

At least Rhomaleosaurus was likely capable of rotational feeding, and Simolestes reached a lenght of 10m and showed a similar skull morphology. Unfortunately, there is very little scientific information about it.

Also, in the above paper something is stated about a 17m long pliosaur, and Forrest didn´t mean P. macromerus, as it is mentioned seperately (as Stretosaurus/ Liopleurodon macromerus)

The most dangerous extinct predators to Man ?
I agree about the other animals, but there are estimates of 15m for Saurophaganax.

Dinodata: Saurophaganax

Saurophaganax was one of the largest carnivores of Late Jurassic North America. Ray even gave an estimate of the body length of fifteen metres and Chure of fourteen, though later estimations have been lower.

Wikipedia: Saurophaganax

That later estimates are lower doesn´t mean that they are accurate. I believe in the 15m figure for the reasons stated above.

Also, I think the bulk of Tyrannosaurus is overestimated. The 9t figure for Sue seems quite unlikely, and when looking at the corresponding reconstruction (http://www.dinosaurier.org/wp-content/uploads/2011/11/trex-plosone-modell2.jpg), it seems way too bulky (Since when is the pubis connected with the ribcage in a more or less straight line? all reconstructions of non-avian-dinosaurs that I know depict it to be discontinued from the rest of the body!). Certainly T rex was relatively massive, but it also had hollow bones and it´s limbs seem to be fairly well adapted for fast accelleration. A maximum of ~7t seems reasonable (1.).
This wouldn´t be the first time for T rex´s size to be exagerated. When it comes to Tyrannosaurs, even scientists tend to be very subjective, and I guess many of the rather low estimates for Charcharodontosaurs were made to make rexy look bigger (unluckily, there are no complete skeletons, so it isn´t possible to give exact size estimates).

Allosaurs might were more slender, but their bones weren´t hollow. Using a 10m, 2,5t Allosaurus, a weight of at least 7t for a 15m specimen is completely reasonable (actually I got a weight of 8,4t).

see also:
1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004532

Spinosaurus bite force
So spino certainly needed quite a strong jaw. also it´s skull looks quite robust, so it is probably really very underrated.

Pantanal Jaguar v Epicyon haydeni
May 10 2012, 04:17 AM
May 10 2012, 03:39 AM
Jaguars can take on animals much larger then themselves (e.g. large anakondas and caimans, even in water).
imo a jaguar will be more than a match for epicyon. they are incredibly strong, their bite is stong enough to crush turtles and they are the only cats that regularly kill by biting into their prey´s head.
Really hard fight. It would probably be 50/50 due to the dogs weight advantage, but remember, the jaguar doesn´t have a problem defeating Caimans, even in water.
at max weight I don't give the jaguar much of a chance at all.
There can only be a real fight if the animals are both similar in size.

The reptiles the jaguar hunts may be impressive, but are nothing compared to a larger member of carnivora like Epicyon

size comparison
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Physical characteristics
The head of the jaguar is robust and the jaw extremely powerful. The size of jaguars tends to increase the farther south they are located.

The jaguar is a compact and well-muscled animal. Size and weight vary considerably: weights are normally in the range of 56–96 kilograms (124–211 lb). Larger males have been recorded to weigh as much as 160 kg (350 lb)[26] (roughly matching a tigress or lioness), and the smallest females have low weights of 36 kg (79 lb). Females are typically 10–20% smaller than males. The length of the cats varies from 1.2 to 1.95 m (3.9 to 6.4 ft), and their tails may add a further 45 to 75 cm (18 to 30 in).[27][28] It stands 63 to 76 cm (25 to 30 in) tall at the shoulders.[29] Like the slightly smaller Old World leopard, this cat is relatively short and stocky in build.[20]

Further variations in size have been observed across regions and habitats, with size tending to increase from the north to south. A study of the jaguar in the Chamela-Cuixmala Biosphere Reserve on the Mexican Pacific coast, showed ranges of just about 50 kilograms (110 lb), about the size of the cougar.[30] By contrast, a study of the jaguar in the Brazilian Pantanal region found average weights of 100 kilograms (220 lb), and weights of 136 kilograms (300 lb) or more are not uncommon in old males.[31] Forest jaguars are frequently darker and considerably smaller than those found in open areas (the Pantanal is an open wetland basin), possibly due to the smaller numbers of large, herbivorous prey in forest areas.[32]

A short and stocky limb structure makes the jaguar adept at climbing, crawling and swimming.[29] The head is robust and the jaw extremely powerful. The jaguar has the strongest bite of all felids, capable of biting down with 2,000 pounds-force (8,900 N). This is twice the strength of a lion and the second strongest of all mammals after the spotted hyena; this strength adaptation allows the jaguar to pierce turtle shells.[4] A comparative study of bite force adjusted for body size ranked it as the top felid, alongside the clouded leopard and ahead of the lion and tiger.[33] It has been reported that "an individual jaguar can drag a 360 kg (800 lb) bull 8 m (25 ft) in its jaws and pulverize the heaviest bones".[34] The jaguar hunts wild animals weighing up to 300 kilograms (660 lb) in dense jungle, and its short and sturdy physique is thus an adaptation to its prey and environment. The base coat of the jaguar is generally a tawny yellow, but can range to reddish-brown and black, for most of the body. However the ventral areas are white.[29] The cat is covered in rosettes for camouflage in the dappled light of its forest habitat. The spots vary over individual coats and between individual jaguars: rosettes may include one or several dots, and the shapes of the dots vary. The spots on the head and neck are generally solid, as are those on the tail, where they may merge to form a band.

While the jaguar closely resembles the leopard, it is sturdier and heavier, and the two animals can be distinguished by their rosettes: the rosettes on a jaguar's coat are larger, fewer in number, usually darker, and have thicker lines and small spots in the middle that the leopard lacks. Jaguars also have rounder heads and shorter, stockier limbs compared to leopards.[35]

(wikipedia: jaguar)

There isn´t that much of a size difference, only 10kg when you use the maximum weights, so I don´t think your scale is accurate, although it looks really good.
Note what is stated about the biteforce! This is an enourmous force.

The most dangerous extinct predators to Man ?
May 11 2012, 03:50 AM
Cave hyenas and short-faced bears have both been listed as reasons why humans colonised North America only after having colonised South America. If true, this is a huge deal: these predators were so dangerous, people actually went through the trouble of crossing an ocean to reach South America rather than risk walking through the Bering Land Bridge.
But there were short faced bears in South america too, even larger ones!

I think Dinocrucuta could have been an enourmous threath to humans, as well as short faced bears, Phorusrhacids and most medium sized teropods (I just imagine a utahraptor chasing a Human).
Actually, the largest allosaurus specimens were possibly a good deal larger than Tyrannosaurus (Saurophaganax/A. maximus is often estimated at 15m, and this doesn´t seem unlikely as there were very large Sauropods-certainly enough food to sustain extremely large Predators), but I agree that Allo was faster and thus a greater threath.

Crocodile - Shark interactions
Crocodiles can be incredibly fast and their agility in water is underrated.
Of course a shark would usually win, simply because it is far larger and it´s girth is so large that a croc couldn´t easily get a bite out of it.