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Post by brobear on Jun 26, 2021 11:00:32 GMT -5
This is not a face-off topic. I believe that a physical comparison between Smilodon populator and a brown bear of similar size would be interesting to research.
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Post by brobear on Jun 26, 2021 11:03:13 GMT -5
Smilodon (Femur/Humerus comparisons per Christiansen and Harris, 2005)Smilodon Gracilis
Femur Length: 269mm (n=1) Femur Circumference: 70.5mm (n=1) Femur Stoutness Index: 26.21% Humerus Length: 247.75mm (n=4) Humerus Circumference: 81.5mm (n=4) Humerus Stoutness Index: 32.9% Smilodon FatalisFemur Length: 391.53mm (n=6) Femur Circumference: 112.5mm (n=6) Femur Stoutness Index: 28.73% Humerus Length: 361.4mm (n=6) Humerus Circumference: 121.17mm (n=6) Humerus Stoutness Index: 33.53% Smilodon PopulatorFemur Length: 390.2mm (n=1) Femur Circumference: 134.5mm (n=1) Femur Stoutness Index: 34.47% Humerus Length: 365.17mm (n=3) Humerus Circumference: 147.5mm (n=3) Humerus Stoutness Index: 40.39% 1. Smilodon Populator was the most robust cat out of the three; not just due to size but also on a proportional basis. The proportional differences between Fatalis/Gracilis are minor whereas Populator exceeds both of them quite handily.
2. Smilodon Populator had a shortened Femur bone in relation to the Humerus bone which gave it a "slope" downwards when looking at it from the side, the posterior part of the torso was situated lower than the anterior part. This characteristic is also visible on the ancient Ursus Spelaeus.
3. In comparison to modern big cats these ancient brutes had way more robust skeletons and were actually closer related to bears than to cats in this regard; one reason why they were more dependant on ambushing their prey than our modern Panthera cats. The short tail and robust frame weren't indications for agility/balance/speed, the focus was set on strength and prey could easily run away when timing wasn't perfect.
Let's compare this ( possibly ) strongest of the big cats to a brown bear of similar size - bones, musculature, etc.
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Post by brobear on Jun 26, 2021 11:06:35 GMT -5
I had began discussing "Smilodon" under the topic "Pleistocene Grizzly" but I have decided that this discussion deserves it's own page. First posted by Tigerluver ( biologist ). wildfact.com/forum/ Smilodon populator - A new fossil and questions about bone robusticity to cursoriality, among other issues Browsing through some older document, I found one of great insight to Smilodon fatalis and S. populator morphology, Relationships between North and South American Smilodon by Björn Kurtén and Lars Werdelin. The differences between the forms were analyzed by this work, and you can read up on it in the attachment. Postcranial anatomy interests me the most. For one, I found a record size humerus of 410 mm. Isometrically comparing to the bear humerus of 400.5 mm, this specimen would be about 470 kg (a post on p. 1 explains why bears may be better isometric basis for this species). This humerus puts S. populator back at the top of felid weights. But there's a caveat. The same document found that "the forelimb of S. populator is somewhat longer, relative to the hindlimb, than in S. fatalis. Such a lengthening of the forelimb is a characteristic of the open plains." An example of this observation is the fact that lion has a proportionally longer humerus and ulna compared to the hindlimb bones, being the only big cat living almost exclusively in the open plains. This morphological characteristic results in overestimation of mass from all bone measurements when comparing to a more average proportional individual. Bone length overestimates because the bone is disproportionately long, and width dimensions overestimate because the width is more for accommodating running stress than muscle in such cases. The brown bear has much shorter frontlimbs than hindlimbs are compared to S. populator, and a bit shorter proportions compared to S. fatalis. In this form, S. fatalis is more robust and bear-like than S. populator, but neither were probably as muscular as a bear, but rather some of the bone width was more for running stress similarly to how lions bones have widened so greatly as compared to other cats. With that, the S. populator estimation using the brown bear as the base is probably an overestimate, or faulty at the least. S. fatalis reconstructions from a brown bear may be a bit less of an overestimate. Smilodon would lack the posterior weight the bear would in the this areas due to the FL/HL discrepancy, and thus the two species are not analogous, at least for humerus calculations. It is very possible the opposite effects of mass estimation would occur if a brown bear femur is being compared to the proportionately shorter Smilodon femur. Smilodon's femur is proportionately much larger than its tibia compared to all pantherines by a long ways. Its humerus is also proportionately larger than its ulna, a ratio only matched by the very robust leopard and jaguar. The longer proximal bones is indicative of the fact that Smilodon is indeed much more heavily built than the lion and the tiger, and somewhat more heavyset than the leopard and jaguar. From this, maybe the best route of Smilodon reconstruction would be one width dimensions and/or the length dimension of the bone, either allometrically or isometrically compared to only jaguars and leopards. The type of bone being used would also have to be taken into account to predict the accuracy of the estimation. Forelimb estimates may be overestimates somewhat, and vice versa for hindlimb estimates. Pictured here is a brown bear and Smilodon fatalis.
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Post by OldGreenGrolar on Jun 26, 2021 17:06:21 GMT -5
As robust as a smilodon is, the brown bear still looks bulkier, hence, and being a plantigrade will hit harder than the Sabre toothed cat.
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Post by brobear on Jun 29, 2021 5:44:52 GMT -5
When being compared at equal weights, I believe that a typical male full-grown brown bear has perhaps a slight over-all strength advantage over a fully-grown male tiger. However, it takes a robust Machairodontinae, such as Smilodon populator, to contest the strength of a brown bear at equal head-and-body length ( IMO ). There is little difference in size between Smilodon fatalis and the Ussuri brown bear of the R.F.E.
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Post by OldGreenGrolar on Sept 18, 2021 7:28:36 GMT -5
Book, Smilodon: the iconic sabertooth. Wroe (2008) suggestes that Smilodon lumbar vertebrae are ursid-like in being shorter craniocaudally than most felids, but still have transverse processes oriented in the matter of felids, giving them BETTER ACCELERATION AND LESS STABILITY THAN URSIDS. books.google.com/books?id=fmBVDwAAQBAJ&pg=PT297&dq=Ursids+are+superior+than+felids&hl=en&sa=X&ved=0ahUKEwiNwc2Q1YXlAhVCuVkKHac3CQMQ6AEIHzAA#v=onepage&q=Ursids%20are%20superior%20than%20felids&f=false From King Kodiak.
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Post by brobear on Oct 22, 2021 2:53:02 GMT -5
GrizzlyClaws: Let's us take a look about the comparison of the entire skeleton. IMO, S.populator could have slightly upper hand in term of the limb bones. However, the torso domain would still go to the Brown bear. As anatomically, the bear got quite different body structure from feline as a plantigrade animal, it has more centered toward the leverage of the torso.
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Post by brobear on Oct 22, 2021 2:54:57 GMT -5
tigerluver: From Christiansen and Harris (2005) and Campione and Evans (2012) we can show a comparison.
Campione and Evans (2012) report a bear humerus 400.5 mm long and 146.25 mm in circumference (robusticity index 0.365). The closest in length humerus reported by Christiansen and Harris (2005) is 387.5 mm long and 155 mm in circumference (robusticity index 0.4). So from this small sample size, Smilodon populator is more robust in the humerus. In the femur, the bear femur was 445.5 mm long and 126.25 mm in circumference (index 0.28). The longest S. populator femur in Christiansen and Harris (2005) was 390.4 mm long and 113.5 mm in circumference (index 0.29). S. populator was front heavy while bears are more balanced so that skews the comparison somewhat. Nonetheless it appears S. populator bone-wise is more robust.
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Post by brobear on Oct 23, 2021 4:00:36 GMT -5
www.researchgate.net/publication/7531697_Body_size_ofSmilodon_Mammalia_Felidae The body masses of the three large saber-toothed machairodontines, Smilodon gracilis, S. fatalis, and S. populator, were estimated on the basis of 36 osteological variables from the appendicular skeleton of extant felids. A new model is introduced that takes the reliability of the predictor equations into account, since mass estimates are more reliable when computed from multiple variables per bone. At a body mass range of 55-100 kg, S. gracilis was comparable in size to extant jaguars, and S. fatalis was found to be somewhat lighter than previously assumed, with a body mass range of 160-280 kg, similar to that of the largest extant felid, the Siberian tiger. Smilodon populator was substantially heavier and larger than any extant felid, with a body mass range of 220-360 kg. Particularly large specimens of S. populator almost certainly exceeded 400 kg in body mass. The differences from previous estimates are most likely caused by differences in the databases used for mass estimation. 400kg = 881.85 pounds.
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Post by OldGreenGrolar on Oct 23, 2021 4:37:46 GMT -5
Reply 6. Nice comparison from GrizzlyClaws.
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Post by brobear on Oct 23, 2021 4:47:57 GMT -5
Reply 6. Nice comparison from GrizzlyClaws. I agree, and in reply #7, tigerluver concludes, "Nonetheless it appears S. populator bone-wise is more robust." *Bone-wise meaning not necessarily in muscle.
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Post by OldGreenGrolar on Oct 23, 2021 4:50:55 GMT -5
/\ The smilodon might have more robust limbs but the brown bear has stronger deltoid muscles and being a plantigrade can hit harder than the Sabre toothed cat. This also makes the brown bear a better grappler.
The brown bear having a shorter back bone would most likely but stronger in a different aspect. I think it will be a close fight.
Regarding shorter backbone = stronger. I posted that information from a book of mine which is lost somewhere in the forum but it is when comparing lion and brown bear.
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Post by brobear on Oct 27, 2021 4:02:32 GMT -5
( IMO ) Should the arms of Smilodon populator be stronger than those of an equal-sized brown bear, as some biologists claim, and which I neither deny nor accept without actually seeing the comparison reports, this still does not prove that the great saber-toothed cat had stronger upper-body strength than an equal-sized brown bear. We must also consider those massive shoulders of the brown bear; muscles so massive that they form a hump on his back. That shoulder hump is a mountain of muscles. From Frank321.... The author makes an effort to show the tremendous quality of muscle and skeletal frame of the ursines. We need to look at bear behavior to find out why bears need such muscles, rather than making the assertion based on accounts at first, in order to show that this is what bears are designed for. We'll use the diet of American black, brown, and polar bears to recognize these adaptions.
Ursus americanus (Omnivorous)
Honey, beetles, ants, roots, twigs, buds, and on rare occasion, meat, including young elk.
Ursus arctos (Omnivorous)
Peaches, apples, apricots, salmon, elk, musk ox, occasionally bison, sedge, and other vegetation.
Ursus maritimus (Mostly Carnivorous)
Ringed seal, bearded seal, beluga whale, walrus, narwhal, and rare vegetation.
While it might seem obvious which one of these is the most impressive in regards to strength optimization based on diet, things are actually the exact opposite. To understand this, let's review the basic properties of leverage for a quick moment; the longer a lever, the less the strength or weight allowed on the lever, although the greater the speed at the end of a lever.
As we can see, strength optomization in regards to ursines is the exact opposite from impressness in diet; black bears have the best leverage for strength, and polar bears the worst. At least, in terms of limb length anyway. So now, the question why must be asked. We will find this answer by looking at the habitat of each ursine. Black bears can be found in areas such as forests; generally with a lot of trees. Brown bears are more closely associated with areas such as the bottom of river valleys, and fields of sedge. Polar bears are found in more remote areas and circumpolar regions. It seems that, in areas that are more condensed such as forests, and have many rocks and the like we will find animals with shorter limbs, if not relative to their families. This can be seen with the felidae, in which the lion has the longest limbs of the Pantherinae living in open fields, whereas jaguars have relatively the shortest living in condensed forests with rivers and boulders. This would mean that, to flip over heavy boulders and swim through powerful currents and the like, while still maintaining the strength to climb trees, animals who live in forests will generally have shorter limbs. Whereas, in more open areas, where such things are irrelevant, and speed really matters we will have animals with longer limbs being adapted for speed.
Now that we have looked at the diet of bears, and how this influences leverage (strength and speed), we will look at their threats and predators and how this influences their behavior to threats and how it affects them as in regards to evolving to deal with them. Black bears are generally not very large relative to the apex predators the coexist with. For example, in what is now a part of the old USSR Siberian tigers will prey on them. They aren't well adapted to deal with these massive cats and are generally the submissive ones, the book Mammas of the Soviet Union supports this with accounts of tiger-Asiatic black bear interaction.
They do have defenses. Asiatic black bears are better climbers than Siberian tigers due to having claws better adapted to do so; they escape the threat of a tiger generally by climbing, and because of this are less likely to be preyed on by them (although it has happened.) This is supported by once again, the book Mammals of the Soviet Union.
So now how does the Manchurian brown bear evolve to deal with a predator which it can't climb from to escape, and is too fast to outrun. It evolves to deal with it in a confrontation; brown bears have evolved thick, loose fur around their necks to protect them from tiger bites, and their thick fur on their torso and limbs gives them good protection against the claws of tigers and other ursines. They have also evolved into bulkier animals which are more heavy-set (will be discussed more in section 2.2 and 3.0.) Grizzly bears coexisted with Machairdontinae felids during the Pleistocene; it's likely grizzlies didn't evolve to deal with these felines due to the fact they wouldn't prey on them because they needed larger prey and would perhaps have difficulty catching them as well.
In the following sub-sections, we will look at the anatomy of bears, and for section 2.3 brown bears respectively. This will allow us to make connections to the neuromuscular evolution which we made earlier. We will start out with the chest of ursines and compare them with felids. The lion will be the first animal we start out with - the book Into Africa [pg. 41] by Dr. Craig Packer gives the chest girth estimate for a Serengetti lion, it writes- His chest girth is 48 inches. His weight must therefor be be about 350 pounds, fairly average for a Serengetti male.
This is the exact estimate made for 350 pound American black bears in Pennsylvania (Alt 1980), from this - . The more massive chested grizzly bear beats both the lion, and its cousin the American black bear in this regard, credits to Ursus arctos for the following (it should be noted these bears would have had a good amount of body fat when captured, due to being caught in fall, rather than spring where they are at their most muscular)-
As a general consensus however, most all species bear seem to have chests larger than hypercarnivores relative to body size including the felidae when considering largest, or most dominant individuals. Evidence of this is shown in the book Black Bear Hunting on pages 18 and 19-
Manitoba's heaviest bear was by a car on the Province's route 11 near Traverse Bay on the southeast end of Lake Winnipeg during the evening of August 30, 2001. The carcass wasn't officially weighed until September 5, according to Department of Conservation Wildlife Technician Trevor Barker at Lac du Bonnet, and it tipped the scales at 856 1/2 pounds then. Based on a loss of fluids before the bruin was weighed, the animal had an estimated live weight of 886.5 pounds... ... The chest girth was 6.5 feet.The right front paw was 5 1/2 inches wide and rear foot was 9 7/8 inches in length.
We can compare the chest girth of this black bear (estimated fluid weight) with other tigers using mathematics. The chest girth of tigers and lions comes from the book Thirty-seven Years of Big Game Shooting in Cooch Behar, the Duars, and Assam (credits to the Bold Champ for finding it, and Ursus arctos for supplying it to Carnivora), the conversions will be made in this chart-
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Post by brobear on Oct 27, 2021 4:03:39 GMT -5
Continued.... 183 kilogram tiger, - 2.2^(1/3)=1.300 119+30%=155
200 kg tiger,- 2.01^(1/3)=1.26 130+26%=164
230 kg tiger,- 1.75^(1/3)=1.21 137+21%=165.77
191 kg tiger,- 2.11^(1/3)=1.28 130+28%=166.4
225 kg tiger,- 1.8^(1/3)=1.22 131+22%=159.82
187 kg lion,- 2.2^(1/3)=1.300 147+30%=191.1 Tiger mean=162.2 centimeters (five individuals)
Lion mean=191.1 centimeters (one individual)
Overall feline mean= 167.015 centimeters (six individuals)
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Post by brobear on Oct 27, 2021 4:05:44 GMT -5
Only a particular lion approached the black bear in chest girth, and all tigers didn't come close. We can compare the chest girth of 866.5 pound black bear relative to other brown bears from charts the book California Grizzly and a chart listing seperate chest girths of brown bears (credits to the bold champ, Ursus arctos, and Warsaw for providing this information.)
The book California Grizzly had the estimated bear's median at 250 kilograms (227-270 kilograms) with a chest girth of 180 centimeters, this will be used when calculating this particular bear's chest girth.
225 kilogram grizzly (male),-
1.61^(1/3)=1.21
180+21%=217.8
115 kilogram grizzly (female),
3.5^(1/3)=1.52
105.5+52%=160.6
115 kilogram grizzly (female),
3.5^(1/3)=1.52
96+52%=145.92
85 kilogram grizzly (female),-
4.61^)1/3)=1.67
87.5+67%=146.125
145 kilogram grizzly(female),-
2.8^(1/3)=1.41
112+41%=158
151 kilogram grizzly (female),- 2.67^(1/3)=1.4
114+40%=162.15
150 kilogram grizzly (female),-
2.7^(1/3)=1.4
129+40%=180.6
115 kilogram grizzly (female),-
3.5^(1/3)=1.52
107.9+52%=164.02
112 kilogram grizzly (female),-
3.6^(1/3)=1.53
99.5+53%=152.24
75 kilogram grizzly (male),-
5.37^(1/3)=1.75
103+75%=180.25
145 kilogram grizzly (male),-
2.8^(1/3)=1.41
113+41%=145.23
145 kilogram grizzly (male),-
2.8^(1/3)=1.41
112+41%=157.91
200 kilogram grizzly (male),-
2.01^(1/3)=1.26 155+26%=195.3
200 kilogram grizzly (male),-
2.01^(1/3)=1.26
146+26%=184
100 kilogram grizzly (male),-
4.03^(1/3)=1.6
97+60%=150.3
135 kilogram grizzly (male),-
3.0^(1/3)=1.44
123+44%=177.12
130 kilogram grizzly (male),-
3.1^(1/3)=1.46
100+46%=146
100 kilogram grizzly (male),-
4.03^(1/3)=1.6
126.5+60%=202.5
57 kilogram grizzly (male),-
7.1^(1/3)=1.92
80+92%=154
275 kilogram grizzly (male),-
1.4^(1/3)=1.2
145+12%=162.4 female chest girth mean=158.71 centimeters (eight individuals)
male chest girth mean=172.73 centimeters (12 individuals.)
Black bear mean=198.12 centimeters (one individual.)
Overall bear mean=174.7 centimeters (21 individuals.)
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Post by brobear on Oct 27, 2021 4:06:57 GMT -5
Continued.... Forelimb girth for felids and usrines, is a more complicated matter, as there seems to be a lack of information on bears. However, according to many posters, Royal Leo posted information which showed that black bears are similar to tigers in forelimb girth, and larger than lions relative to size, although grizzlies had larger girths than all of these animals. This information comes from, bcw3, and 221extra (as a note, 221extra hasn't talked about the study, although he has confirmed he did in fact post it.) However, while we will use Royal_Leo's study, I would like to post a pictorial comparison Ursus arctos created in order to show relative arm girth. However, for this actual the study we won't assume the difference in arm girth is as large as that suggested by the pictures, as Royal Leo's study seemed to contradict this according to posters- It's time to look back at the leverage scenario once more, felines have greater leverage for strength than similar-sized ursines (see chart in section 1.0), due to having shorter limbs, however ursines have slightly larger arm girths relative to body size. What does this mean, and why? To understand this we need to look at the volume. We know that if we want to increase the limb weight of an animal, we must either make it wider, or longer in order to increase volume for weight. In both of these aspects, ursines are superior to felids, as in having wider, although longer limbs. However, there's a catch, how do we know that the forelimbs of ursines aren't fat, which although takes up more space than muscle, is lighter. This was proven in my analysis "Comparitive Relative Strength of Bears and Cats" where it was shown that the far bears pack on in winter is sent to their hips, rather than forequarters ( www.asbweb.org/conferences/2007/425.pdf ). So now another question must be asked, why not simply gain the greater relative weight in the limbs by increasing volume more so vertical, than horizontal? We must look at the kinetic energy, and leverage for this answer. The formula for kinetic energy is - KE= 1/2*m*v^2 - so how is this relevant to ursines? We must look back at the basic properties of leverage - While increasing the length between the end of a lever, and its fulcrum will increase the speed, it will decrease the strength. The reverse is true when decreasing the distance between the fulcrum and the end of a lever, of course. In this regard, ursines have the leverage advantage in velocity for kinetic energy when concerning limb movement against felids, and it's likely this is the reason for missing out on the greater strength provided by simply increasing limb weight horizontally. By all accounts, there doesn't seem to be another animal similar in size to ursines which can deliver as devestating a blow, there is evidence to suggest this in the book Black Bear Hunting., Richard P. Smith : pg. 31-32- Although most black bears limit their predation to young animals, some larger adult males learn to catch and kill animals as large as moose. Most people might scoff the idea of a 300- to 500-pound bear attacking a moose weighing over 1,000 pounds, but it does happen. Predation on adult moose by large male bears has been documented a number of times in Canada. Ontario bear researcher Dr. Martyn Obbard and his colleagues documented predation of an adult cow moose by an adult male black bear on the Chapleau Game Reserve during May 1992. A report of the incident was published in the volume 108 of the Canadian Field-Naturalist. In the case of the adult moose being killed, the predatory bear was an 18-year-old male weighing about 300 pounds and fitted with a radio collar... One other Canadian province where black bear predation has been documented is Newfoundland. A researcher there, Shane Mahoney, told me he has recorded a number of cases where adult male bears weighing 300 to 350 pounds have killed adult moose and caribou. One instance he mentioned involved an adult moose that was attacked by a large male as it bedded like the one in Ontario. In that situation, the bear killed the moose with a blow to the back from a paw, smashing the spine... A big bear was actually observed killing a cow moose in the water during another case of predation. Mahoney said the water was too deep for the bruin to get much leverage where the moose was originally attacked, but as the moose move toward shore and got into shallow water, odds turned in the bear's favor. Once the bruin was able to get to its feet on the bottom, it brought the cow down with a swatt to the spine.
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Post by brobear on Oct 27, 2021 4:08:10 GMT -5
Continued.... To start out with this chapter, I would like to look at the length of a ursine and felid's back, on average (credits to Taipan), and the following table is from largest to smallest in meters-
lower-upper Tiger 2.20 3.30 Lion 2.00 2.80 Cougar 1.00 2.00 Leopard 0.90 1.90 Jaguar 1.00 1.80 Cheetah 1.00 1.50 Snow Leopard 1.00 1.30 Lynx 0.80 1.30 Asian Golden Cat 0.73 1.10 Serval 0.67 1.00 Bobcat 0.65 1.00 Clouded Leopard 0.60 1.00 Ocelot 0.55 1.00 African Golden Cat 0.72 0.95 Chinese Desert Cat 0.68 0.94 Caracal 0.60 0.90 Fishing Cat 0.72 0.86 Margay 0.45 0.80 Jaguarundi 0.60 0.77 Jungle Cat 0.60 0.75 Wild Cat 0.50 0.75 Pampas Cat 0.56 0.70 Geoffrey's Cat 0.45 0.70 Pallas Cat 0.50 0.65 Bay Cat 0.50 0.60 Iriomote Cat 0.50 0.60 Andean Mountain Cat 0.48 0.60 Leopard Cat 0.44 0.60 Sand Cat 0.45 0.57 Litle Spotted Cat 0.40 0.55 Flat-headed Cat 0.40 0.55 Marbled Cat 0.45 0.53 Black-footed Cat 0.40 0.50 Kodkod 0.38 0.48 Rusty-Spotted Cat 0.40 0.45
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Post by brobear on Oct 27, 2021 4:09:23 GMT -5
Continued.... Now to compare it to that of ursines, the book The Great Bear Almanac by Gary Brown, lists the length of ursines on page 64, I will make a list giving these lengths- American black bear 4-6 feet, brown bear 7-10 feet, polar bear 8-8.4 feet, Asiatic black bear 5-7 feet, giant panda 5-6 feet, sloth bear 5-6 feet, sun bear 3-4.5 feet, spectacled bear 4-7 feet. Relative to ursines, felids seem to have much longer backs. So once more, the question must be asked, what does this mean? It shows bears are more powerfully built in their back; looking back at the properties of leverage once more, we know that shorter levers allow more weight to be placed on a lever, the shorter back of a ursid allows the spinal cord to hold greater amounts of muscle than felids.
This is shown in the height of the back of the families, where much smaller ursids can have backs as high as those of the largest felines as shown by this source (http://www.americanbear.org/Size.htm)- The height of a bear is measured from the bottom of its paw, flat on the ground, to the highest point of the shoulders. An adult male American black bear will measure between 2½ and 3 feet tall. This is approximately the same height as a Siberian tiger.
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Post by brobear on Oct 27, 2021 4:10:06 GMT -5
Continued.... Since limb bones are placed vertical however, unlike the spinal cord, leverage to support more amounts of muscle in this area is irrelevant. However, there must be an advantage to having a longer backs, or else evolution would supply all quadrupeds with shorter backs. There is; having a longer back increases stride length in quadrupeds, and stride length is directly correlated with speed since speed is stride length*frequency. This means, at least in the back felids are better adapted for speed than ursines, and suggests so overall as well.
This also suggests ursines once again, have an adaption for producing tremendous force in their paw swipes, since delivering a paw swipe contracts the muscles in an animal's back, and more amounts of muscle allows greater force to accelerate with, and force and acceleration are directly correlated. We know this via Newton's second.
Now, for the abudctor muscles. Earlier in this thread it was shown that all (or the majority of) the fat that bears gain during fall is sent to the hips. This seems to be supported by images as well. Felines on the other hand, would presumeably have more muscle than fat in this area due to having relatively less fat than bears throughout the full cycle of seasons (perhaps except the Siberian tiger, although this animal might have fat sent to other areas other than the hips, needing its hindquarters as springs to leap onto prey.)
Information on the abductor muscles of both animals, however is quite limited and we'll have to wait until more data arises until we can make a more comprehensive comparison.
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Post by brobear on Oct 27, 2021 4:10:34 GMT -5
qwaszx! Shoulder Hump**** This section will be given to the brown bear amongst ursines soley. We'll start out with a quote from the Great Bear Almanac, by Gary Brown on page 77- Brown bears have a hump between their shoulders that is covered with long hairs and is normally a reliable means of species identification. The long hair often accentuates the hump when "the hackles" are raised. This distinguishing feature is a distinctive mass of muscle that provides the brown bears with their digging ability and the powerful striking force of the forepaws. Once again, another part of brown bear anatomy (although other bears have similar features which shows why they can accomplish similar feats) which allows for tremendous striking force of the paws. However, this extra muscle also allows extra strength, as have other features such as the shortened back, greater amount of muscle in the limbs of bears, and leverage advantage in paw striking. Other ursines such as the black bear and polar bear, have this feature abridged, and felines lack it entirely. How large can the shoulder hump get however? Let's find out how high first, this source mentions how the bear's height is measured and than gives it (http://internationalhunte.../InteriorBearAnatomy.html)- The brown bear is 3-5 feet, from the bottom of the paw to the highest point at the shoulder. We can subtract this height from the limb length of Ursus arctos in the chart shown in section 1.0 to find the height of the shoulder hump. Ursus arctos's forelimb length is 2.857, subtracting this from three and five feet gives us a range of .143-2.143 feet. I would assume that only the largest bears would of roughly half a ton in weight would have a shoulder hump of two feet, whereas only the smallest would be within the range of .143 of a foot. However, since maximums and minimals don't particularly show averages, we will search for the average height of the grizzly, this source (http://www.bearinfosite.com/brown_grizzly_bear.htm ) gives an average- The adult bear is generally 3 1/2 feet tall when on all fours.
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