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Post by OldGreenGrolar on Jun 9, 2019 7:07:25 GMT -5
Some say the hyenas bite force is overrated. Whiles its true that hyenas have stiff limbs which makes them poor grapplers, they still have jaws that can crush bones that even lion's jaws can't crack.
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Post by King Kodiak on Jul 16, 2019 5:37:34 GMT -5
LOOKS LIKE POLAR BEARS AND GIANT PANDAS HAVE THE HIGHEST BITE FORCE AMONG BEARS AND HIGHER THAN ALL FELINES. When standardized to size (Panel A), bears look less extreme. They actually tend to cluster lower down the curve, which means that, given their size, they are less well built to deliver bite force compared to many other carnivore species, especially of the Felids and Canids. The noteworthy exceptions are the polar bear (Uma) and the giant panda (Ame), which is not surprising. The polar bear is the most carnivorous of all bears (meaning, it needs to grasp and hold prey), whereas the panda is the most herbivorous (meaning it needs a powerful bite to grind the bamboo that comprises most of its diet). www.allgrizzly.org/skull--dentition
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Post by Deleted on Jul 17, 2019 3:54:31 GMT -5
^ Oh bois, bite force is another confusing topic to discuss. Bite force results tend to vary a lot from studies to studies due to the different methods and specimens the researchers used. It's very difficult to say which study is likely to be more accurate than the others. Anyway, i'm not surprised at all that Polar bears would have had the highest absolute bite force among all extant terrestrial Carnivorans (alongside with Kodiak bears) due to the size of the animals and the size of its skull. However, i'm very surprised that the Polar bears also have high BFQ (Bite Force Quotient - it's basically pounds for pounds Bite force for simplicity sake) according to the source that you posted. In most studies i have seen suggesting somewhat low to medium BFQ for Polar bears. Do you happen to know the primary/academic source of the study in the link you posted?
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Post by King Kodiak on Jul 17, 2019 4:21:40 GMT -5
Well its from the site “All grizzly”, Brobear and me have always gotten very good data from here.
www.allgrizzly.org/skull--dentition
The author of the Site is David Mattson, a scientist and researcher. he has a bachelor's degree in forest management, a master's degree in plant ecology, and a doctoral degree in wildlife ecology.
www.allgrizzly.org/david-mattson
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Post by tom on Jul 17, 2019 5:43:53 GMT -5
The man is well educated.
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Post by Deleted on Jul 17, 2019 9:39:53 GMT -5
Well its from the site “All grizzly”, Brobear and me have always gotten very good data from here.
www.allgrizzly.org/skull--dentition
The author of the Site is David Mattson, a scientist and researcher. he has a bachelor's degree in forest management, a master's degree in plant ecology, and a doctoral degree in wildlife ecology.
www.allgrizzly.org/david-mattson
Regardless, it's still a secondary source not primary source. As you can see in the sites yourself, the bite force study was done Per Christiansen not Mattson. Anyway, here is the primary source so you can check it out yourself. Based on the primary source, i spot an interpretation mistake. The acronym 'Uma' in Panel A actually does not stand for Ursus maritimus but Ursus malayanus aka Sun bear. You can compare the Panels in the All Grizzly site next to Table 1 of the primary source (that i linked). Polar bear Canine BFQ is actually only 92.3 while Sun bear Canine BFQ is up to 160.5, which is among the highest of all Carnivorans. It's most likely just an unintentional mistake but anyway, it shows you that it's always best to look at the primary source yourself instead of putting all your trust on a secondary source. Regarding Mattson, i have never seen an academic paper with his name on it. Perhaps, his area of research does not align with my interest. Also, he does not provide proper academic references for the primary sources that he used in his site, which is really odd for someone who is supposedly familiar with academic practices.
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Post by King Kodiak on Jul 17, 2019 11:37:21 GMT -5
Verdugo: yes you are correct, i did not even bother to look at the primary source. The polar bear’s canine BFQ is actually 92.3. The sun bear’s BFQ is 160.5, followed by the Panda bear which is 151.4. These last 2 still have more than all big cats. Like you said, it was most probable a mistake.
i do see a mistake in the primary source though, the sun bear is not of the Ursus genus, its actually (Helarctos malayanus), did you notice that?
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Post by Deleted on Jul 17, 2019 22:31:50 GMT -5
i do see a mistake in the primary source though, the sun bear is not of the Ursus genus, its actually (Helarctos malayanus), did you notice that? The primary source was published in 2007, perhaps the Sun bear was just recently renamed to Helarctos after that so the paper still used the previous classification for the Sun bear? Regardless, it does not affect the point we're discussing here in anyway. But you got the point here, even primary sources are not always mistake-proof. Regardless, primary sources are still always more credible and convincing the secondary ones.
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Post by King Kodiak on Jul 17, 2019 23:49:36 GMT -5
i do see a mistake in the primary source though, the sun bear is not of the Ursus genus, its actually (Helarctos malayanus), did you notice that? The primary source was published in 2007, perhaps the Sun bear was just recently renamed to Helarctos after that so the paper still used the previous classification for the Sun bear? Regardless, it does not affect the point we're discussing here in anyway. But you got the point here, even primary sources are not always mistake-proof. Regardless, primary sources are still always more credible and convincing the secondary ones. Believe it or not, the Sun bear classification of Helarctos malayanus was in 1821. Maybe it was a typo? Who knows. Anyways, yeah of course, it has nothing to do with the results.
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Post by brobear on Oct 28, 2019 8:11:33 GMT -5
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Post by brobear on Oct 29, 2019 7:26:01 GMT -5
^ Oh bois, bite force is another confusing topic to discuss. Bite force results tend to vary a lot from studies to studies due to the different methods and specimens the researchers used. It's very difficult to say which study is likely to be more accurate than the others. Anyway, i'm not surprised at all that Polar bears would have had the highest absolute bite force among all extant terrestrial Carnivorans (alongside with Kodiak bears) due to the size of the animals and the size of its skull. However, i'm very surprised that the Polar bears also have high BFQ (Bite Force Quotient - it's basically pounds for pounds Bite force for simplicity sake) according to the source that you posted. In most studies i have seen suggesting somewhat low to medium BFQ for Polar bears. Do you happen to know the primary/academic source of the study in the link you posted? I have also noticed the same confusion with polar bear bite force. Some studies give the polar bear a rather weak bite for so huge an animal while other studies give him a rather impressive bite force. Someone is wrong. Because he is a predator, he should have a strong bite. But does he really need a powerful bite to consume most blubber? Of course, to eat blubber, he must first tear through the seal or walrus hide.
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Post by theundertaker45 on Mar 27, 2020 10:05:39 GMT -5
Probably the most popular topic related to morphology/strength: bite force. Today I'll share the latest and probably the only valid study regarding comparative bite forces out there, a work written by Per Christiansen and Stephen Wroe in 2007. Prior to this study, another work was released in 2005 (involving the same authors) but their methods got drastically overhauled and the amount of species/taxa was hugely expanded. This is the abstract of the work: "Abstract. The Carnivora spans the largest ecological and body size diversity of any mammalian order, making it an ideal basis for studies of evolutionary ecology and functional morphology. For animals with different feeding ecologies, it may be expected that bite force represents an important evolutionary adaptation, but studies have been constrained by a lack of bite force data. In this study we present predictions of bite forces for 151 species of extant carnivores, comprising representatives from all eight families and the entire size and ecological spectrum within the order. We show that, when normalized for body size, bite forces differ significantly between the various feeding categories. At opposing extremes and independent of genealogy, consumers of tough fibrous plant material and carnivores preying on large prey both have high bite forces for their size, while bite force adjusted for body mass is low among specialized insectivores. Omnivores and carnivores preying on small prey have more moderate bite forces for their size. These findings indicate that differences in bite force represent important adaptations to and indicators of differing feeding ecologies throughout carnivoran evolution. Our results suggest that the incorporation of bite force data may assist in the construction of more robust evolutionary and palaeontological analyses of feeding ecology."And in their introduction they present the methods of determining the specific bite forces: "Bite forces were estimated using cross-sectional areas for the major jaw adductors: the temporalis and mastermedial pterygoideus muscle complexes (Thomason 1991; see also Christiansen and Adolfssen 2005, Wroe et al. vertebrate striated muscle (Thomason 1991). However, this has resulted in lower than actual bite force values, when compared with muscle dissections on Didelphis skulls (Thomason 1991), probably because actual maximal contractile forces of muscles should ideally be computed from the physiological cross-sectional area (Weijs and Hillen 1984, 1985, Sinclair and Alexander 1987, Koolstra et al. 1988, Cleuren et al. 1995), rather than from estimates of physical cross-sectional areas. Also, the present model does not include other, smaller jaw adductors, such as the zygomaticomandibularis. Accordingly, a slightly higher value of 370 KPa (Weijs and Hillen 1985, Koolstra et al. 1988) was used in the present study. Average body masses for each species were taken from the literature (Nowak 1991, Stirling 1993, Silva and Downing 1995, Kingdon 1997, Reid 1997, Sunquist and Sunquist 2002, MacDonald and Sillero-Zubiri 2004). For sexually dimorphic species, assignment of average body masses was influenced by the proportion of males and females of each species. The relationship between bite force and body mass in carnivorans is allometric and comparisons were, accordingly, made through computation of a bite force quotient or BFQ (Wroe et al. 2005)."
Regarding the ursids involved in the study, we have the following BFQ-ranking (I am focusing on the BFQ at the canine tips as the canines play the major role in delivering a killing bite): 1. Sun Bear - 160.5 at the canine tips 2. Giant Panda - 151.4 at the canine tips 3. Spectacled Bear - 103.1 at the canine tips 4. Brown Bear - 99.3 at the canine tips 5. Asian Black Bear - 95.6 at the canine tips 6. Polar Bear - 92.3 at the canine tips 7. American Black Bear - 77.2 at the canine tips 8. Sloth Bear - 59.9 at the canine tipsHere are some other measurements: Tiger - 130.4 at the canine tipsLion - 123.8 at the canine tipsJaguar - 118.6 at the canine tipsLeopard - 119.8 at the canine tipsCougar - 118.8 at the canine tipsCheetah - 72.7 at the canine tipsGrey Wolf - 127.3 at the canine tipsAfrican Wild Dog - 131.1 at the canine tipsSpotted Hyena - 99.6 at the canine tipsWolverine - 104.6 at the canine tipsWe can see that the sun bear has the proportionally most powerful bite closely followed by the giant panda; then there is a huge gap between the other species with place 3-6 being pretty close in bite force and the sloth bear falling a bit off. Comparing it with other measurements we can see that ursids (except the sun bear and giant panda) are a step behind canids/felids in terms of proportional bite force. It should be noted that the bite of a sloth bear is more than enough to break one's bones though. Just some general facts for the comparison's sake: - The bite force of a ~550lbs brown bear is equal to the bite force of a ~375lbs tiger (~1400N)- A ~130lbs sun bear has a stronger bite than a ~300lbs American black bear (~880N vs ~750N)- The average sloth bear bites as hard as the average steppe wolf (~520N)- Due to his enormous size the polar bear tops the list as the animal with the highest absolute bite force (a 780lbs polar bear would bite down with a force of ~1650N)- As brown bears/polar bears may attain weights of more than 1000lbs they should generally be considered as the carnivores having the highest absolute bite force with the polar bear sitting on top and the brown bear coming close second; third and fourth place would go to the tiger followed by the lion.- The northern olingo has the proportionally highest bite force out of all measured species scoring a BFQ of 162.6 closely followed by the Sulawesi palm civet (161.1) and the sun bear (160.5).Leave your comments/thoughts below and have a great day! Bite Forces and Evolutionary Adaptions.pdf (247.75 KB)
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Post by tom on Mar 27, 2020 11:03:09 GMT -5
Do we have a source for these bite force studies on ursids?
IMO there is no effective way to reliably measure these bite force measurements between different species. At best these are estimates and true bite forces could vary considerably. To rig up a contraption and elicit a defensive bite would be difficult at best on many animals or reptiles,not to mention whether the bite was a maximum effort for the species in question.
If there are actual studies for this I for one would like to see them. So this leaves us with estimates by experts based on make up of each animals jaw and muscle structure.
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Post by theundertaker45 on Mar 27, 2020 11:05:34 GMT -5
Sorry, I forgot to attach the study; I'll edit my initial post. Of course they didn't measure the bite forces in reality, they applied a model to every skull they could find and that were the results. So if they did make a mistake (which I don't know as I am no expert morphologist), it would affect every species.
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Post by tom on Mar 27, 2020 11:21:17 GMT -5
So in essence these are educated estimates by experts and that's all that can realistically be expected because it would be impossible IMO to attempt reliable bite forces on actual animals.
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Post by brobear on Mar 27, 2020 13:20:48 GMT -5
This surprises me: Spotted Hyena - 99.6 at the canine tips. *Perhaps his jaw strength is further back in his jaws? Curious. Oh; by the way. The grizzly is right where I suspected in jaw-strength; a moderate among the bears.
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Post by OldGreenGrolar on Mar 27, 2020 13:44:22 GMT -5
Polar bears have the sharpest teeth of all bears despite not having the best crushing bite. Their bite is more for slicing the thick hide of animals like walrus, beluga, narwhal, and seals.
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Post by King Kodiak on Mar 28, 2020 10:31:30 GMT -5
Taker.....what about in the RFE, would a 595 lb Ussuri brown bear have a higher bite force than a 420 lb Amur tiger?
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Post by theundertaker45 on Mar 28, 2020 10:40:39 GMT -5
The relative weight difference between the two is a bit lower than between a 550lbs brown bear and a 375lbs tiger; therefore the bear will have a slightly higher bite force but only by a few Newtons, nothing noteworthy, their bite force will practically be the same.
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Post by King Kodiak on Mar 28, 2020 10:51:46 GMT -5
Well, its actually the same weight difference (175 lbs). But awesome, they would basically have the same bite force. So morphology speaking, the Amur tiger wont even have that advantage. Much less with the much larger bears.
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