Carcharodon
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Post by Carcharodon on Mar 3, 2014 4:53:00 GMT 5
Great White Shark - Carcharodon carcharias The great white shark, scientific name Carcharodon carcharias, also known as the great white, white pointer, white shark, or white death, is a large lamniform shark found in coastal surface waters in all major oceans. It is known for its size, with the largest individuals known to have approached or exceeded 6 metres (20 ft) in length, and 2,268 kilograms (5,000 lb) in weight. This shark reaches maturity at around 15 years of age and can have a life span of over 30 years. The great white shark is arguably the world's largest known extant macropredatory fish and is one of the primary predators of marine mammals. It is also known to prey upon a variety of other marine animals including fish, pinnipeds, and seabirds. It is the only known surviving species of its genus, Carcharodon, and is ranked first in a list of number of recorded attacks on humans. The IUCN treats the great white shark as vulnerable, while it is included in Appendix II of CITES. Great white sharks live in almost all coastal and offshore waters which have water temperature between 12 and 24 °C (54 and 75 °F), with greater concentrations in the United States (Atlantic Northeast and California), South Africa, Japan, Australia (especially New South Wales and South Australia), New Zealand, Chile, and the Mediterranean. One of the densest known populations is found around Dyer Island, South Africa where much shark research is conducted. It is an epipelagic fish, observed mostly in the presence of rich game like fur seals, sea lions, cetaceans, other sharks, and large bony fish species. In the open ocean it has been recorded at depths as great as 1,220 m (4,000 ft). These findings challenge the traditional notion about the great white as being a coastal species. According to a recent study, California great whites have migrated to an area between Baja California and Hawaii known as White Shark Café to spend at least 100 days before migrating back to Baja. On the journey out, they swim slowly and dive down to around 900 m (3,000 ft). After they arrive, they change behavior and do short dives to about 300 m (1,000 ft) for up to 10 minutes. Another white shark tagged off the South African coast swam to the southern coast of Australia and back within the year. This refuted traditional theories that white sharks are coastal territorial predators and opens up the possibility of interaction between shark populations that were previously thought to be discrete. Why they migrate and what they do at their destination is still unknown. Possibilities include seasonal feeding or mating. The great white shark has a robust large conical snout. The upper and lower lobes on the tail fin are approximately the same size (like some mackerel sharks). Great whites display countershading, having a white underside and a grey dorsal area (sometimes in a brown or blue shade) that gives an overall mottled appearance. The coloration makes it difficult for prey to spot the shark because it breaks up the shark's outline when seen from the side. From above, the darker shade blends with the sea and from below it exposes a minimal silhouette against the sunlight. Great white sharks, like many other sharks, have rows of serrated teeth behind the main ones, ready to replace any that break off. When the shark bites it shakes its head side to side, helping the teeth saw off large chunks of flesh. Males reach maturity at 3.5–4.0 metres (11–13 ft) and females at 4.5–5.0 m (15–16 ft). Adults on average are 4–5.2 m (13–17.1 ft) long and have a mass of 680–1,100 kilograms (1,500–2,400 lb). Females are generally larger than males. It is widely accepted that the great white shark can reach 6.1 m (20 ft) in length and 1,900 kg (4,200 lb) in weight. The maximum size is subject to debate because some reports are rough estimations or speculations performed under questionable circumstances. Great white sharks are carnivorous and prey upon fish (e.g. tuna, rays, other sharks), cetaceans (i.e., dolphins, porpoises, whales), pinnipeds (e.g. seals, fur seals, and sea lions), sea turtles, sea otters, and seabirds. Great whites have also been known to eat objects that they are unable to digest. Although the great white is typically regarded as an apex predator in the wild, it is in rare cases preyed upon by the larger orca (also known as a killer whale).
Dunkleosteus terrelli Dunkleosteus is a genus of prehistoric fish, one of the largest arthrodire placoderms ever to have lived, existing during the Late Devonian period, about 380-360 million years ago. This hunter, measuring up to 6 metres (20 ft) and weighing up to roughly 2 tonnes, was a hypercarnivorous apex predator. Few other placoderms, save, perhaps, its contemporary, Titanichthys, rivaled Dunkleosteus in size. Due to its heavily armoured nature, Dunkleosteus was likely a relatively slow, but powerful, swimmer. It is thought to have dwelled in diverse zones of inshore waters. Fossilization tends to have preserved only the especially armoured frontal sections of specimens, and thus it is uncertain what exactly the hind sections of this ancient fish were like. Instead of teeth, Dunkleosteus possessed two pairs of sharp bony plates which formed a beak-like structure. Dunkleosteus could open its mouth in one-fiftieth of a second, which would have caused a powerful suction that pulled the prey into its mouth, a food-capture technique used by many fish today.
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Deleted
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Post by Deleted on Mar 3, 2014 19:39:54 GMT 5
Dunkleosteus has armor which can protect it from the brunt of the shark's bite, while nothing, as in literally nothing, the shark has can defend against Dunkleosteus' devastating bite. The placoderm's bite is insane! It's bite force may be only around ~4-5.4 kilonewtons, but it's "dentition" just makes it worth more than the first glance at the figure. Massively worth more. Philip A. & Mark W., 2006, "Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator"The final result? Hundreds of millions of pascals! This is no joke. ~107-147 meganewtons/m 2, or ~15,519-21,320.5 pounds/inch 2, if you prefer. This is not a fanboyistic overestimation, this is a serious scientific figure. "The bladed dentition of Dunkleosteus provided for extremely high local bite stress (force/area) because the bite force was focused into a small area, the fang tip (147 million N m-2) or the blade edge (107 million N m-2)."To put that in perspective, the water pressure at the bottom of the deepest point in the Marianas Trench is estimated to be about ~108,592,427 newtons/m 2 (~15,750 pounds/inch 2). In the same ballpark as the FREAKING LOWER FIGURE of Dunkloesteus' bite pressure. This creature is a serious contender for the king of biters. Forget Tyrannosaurus, forget Megalodon, forget Pliosaurus, Dunkleosteus should be among the most cited when it comes to killer bites. It's bite pressure is seriously suspected to surpass the water pressure in the deepest area in the ocean.
I bet it could cut through any biological matter ever on Earth.
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Post by creature386 on Mar 3, 2014 20:35:10 GMT 5
And there were times when I have thought Dunkleosteus' bite was weak… Now I understand why people see it as the strongest biter. Looks like the only hope the great white shark has left is agility.
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Post by theropod on Mar 3, 2014 22:12:01 GMT 5
Hmm, are there comparative figures for bite pressurein other animals? In a sharp-toothed creature bite pressure can be expected to be very high, even if bite force is low. And sharks also have sharp, pointed teeth.
Not saying that’s not a valid point regarding Dunkleosteus though.
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Post by creature386 on Mar 3, 2014 22:26:35 GMT 5
I don't know if there are, but the paper claimed it to be among the strongest biters anyway. So, even if the difference would be a bit lower with a similar figure for the great white, it would still be quite hopeless.
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Post by Grey on Mar 3, 2014 23:38:52 GMT 5
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Post by Runic on Mar 3, 2014 23:44:49 GMT 5
I thought there was a paper that had said their bites were vastly overestimated somewhere on CF? If that's true then I don't see what all the hypes about, I'll have to confirm it though.
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Post by creature386 on Mar 3, 2014 23:52:24 GMT 5
Yeah, but that's the paper @brolyeuphyfusion has cited and it looks like I misinterpreted it.
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Post by Grey on Mar 4, 2014 0:19:03 GMT 5
Yeah, but that's the paper @brolyeuphyfusion has cited and it looks like I misinterpreted it. coherentsheaf too despite being very interested in the bite forces field. If the 36 tonnes at the tip ot the fang claim is exact, Dunk is the record breaker.
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blaze
Paleo-artist
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Post by blaze on Mar 4, 2014 0:22:27 GMT 5
@broly I think you got carried away with the mention of millions in that number, 147 million Nm?2 is only 147 MPa, for comparison, the pressure generated by caniniform teeth of all the crocodilian taxa examined by Erickson et al. (2012) ranged from 195 to 1344 Mpa (yes over one billion newtons per square meter), that later value was generated by the Orinoco crocodile.
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Post by Grey on Mar 4, 2014 0:45:35 GMT 5
@broly I think you got carried away with the mention of millions in that number, 147 million Nm?2 is only 147 MPa, for comparison, the pressure generated by caniniform teeth of all the crocodilian taxa examined by Erickson et al. (2012) ranged from 195 to 1344 Mpa (yes over one billion newtons per square meter), that later value was generated by the Orinoco crocodile. In short terms, these values applied to tip of teeth can be tremendeous in any animal with high bite pressure ?
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Post by creature386 on Mar 4, 2014 0:58:28 GMT 5
@broly I think you got carried away with the mention of millions in that number, 147 million Nm?2 is only 147 MPa, for comparison, the pressure generated by caniniform teeth of all the crocodilian taxa examined by Erickson et al. (2012) ranged from 195 to 1344 Mpa (yes over one billion newtons per square meter), that later value was generated by the Orinoco crocodile. Wow, I really need to read this paper more often, it has so much information I have overlooked (like the length/weight story).
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Post by coherentsheaf on Mar 4, 2014 1:13:46 GMT 5
As blaze remarked, pressure values become high quickly. To illustrate this, take a needle that is pressured by human body mass. Suppose its tip is somewhat narrow measuring 0.01 mm^2 and the man sitting on it weighs 100kg. Then the stress experience at the tip of the needle by the man is: 10 billions kg per square meter. So there you have it. A needle has "more force than Dukleosteus". Of course this calculation is total bollocks if you want to estimate biting potency. So is this:
"The final result? Hundreds of millions of pascals! This is no joke. ~107-147 meganewtons/m2, or ~15,519-21,320.5 pounds/inch2, if you prefer. This is not a fanboyistic overestimation, this is a serious scientific figure.
"The bladed dentition of Dunkleosteus provided for extremely high local bite stress (force/area) because the bite force was focused into a small area, the fang tip (147 million N m-2) or the blade edge (107 million N m-2)."
To put that in perspective, the water pressure at the bottom of the deepest point in the Marianas Trench is estimated to be about ~108,592,427 newtons/m2 (~15,750 pounds/inch2). In the same ballpark as the FREAKING LOWER FIGURE of Dunkloesteus' bite pressure.
This creature is a serious contender for the king of biters. Forget Tyrannosaurus, forget Megalodon, forget Pliosaurus, Dunkleosteus should be among the most cited when it comes to killer bites. It's bite pressure is seriously suspected to surpass the water pressure in the deepest area in the ocean.
I bet it could cut through any biological matter ever on Earth. "
I can assure you, the forces you wuld experience in the mouth of the tyrant king will be be higher than those by Dunkleosteus by an order of magnitude and s are the peak stresses, just like pliosaurs etcetera. Narrow needles, on the other hand, will beat the Tyrannosaur when it comes to peak stress. I hope users will not be as easily duped into believing such nonsensical statments i the future.
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Post by coherentsheaf on Mar 4, 2014 1:17:47 GMT 5
@broly I think you got carried away with the mention of millions in that number, 147 million Nm?2 is only 147 MPa, for comparison, the pressure generated by caniniform teeth of all the crocodilian taxa examined by Erickson et al. (2012) ranged from 195 to 1344 Mpa (yes over one billion newtons per square meter), that later value was generated by the Orinoco crocodile. Wow, I really need to read this paper more often, it has so much information I have overlooked (like the length/weight story). in this case you do not even need to read. Before reading what blaze wrote I did a few quick plausibility calculation and my estimate for stresses in a croc bite was not far off what blaze posted. I think learning to do fermi estimates on the fly will improve your abilities in judging such stuff: www.youtube.com/watch?v=0YzvupOX8Is
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blaze
Paleo-artist
Posts: 766
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Post by blaze on Mar 4, 2014 1:23:36 GMT 5
edit: nvm coherentsheaf already responded haha
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