Xenosmilus hodsonae vs Grizzly bear

[OldGreenGrolar]

Xenosmilus hodsonae.
Xenosmilus is a genus of extinct Machairodontinae, or saber-toothed cat. Two fairly intact specimens were found by amateur fossil hunters, in 1983 (1981 by some sources) in the Haile limestone mines in Alachua County, Florida. In 1994 the fossils were examined, and it was decided that the cats were of an entirely new genus, which has been placed under the tribe Machairodontini. They lived about 1 million years ago, but as there are only two specimens of the same age, when they appeared and when they became extinct is unclear. Currently, there is only one species known, X. hodsonae.Physically, the cat measured between 1.7-1.8 m long with a highly muscular body, even more muscular than any other cat alive or dead, and the animal probably weighed around 230-400 kg. Before their discovery, all known saber-toothed cats fell into two general categories. Dirk toothed cats had long upper canines and stout legs. Scimitar toothed cats had only mildly elongated canines, and long legs. Xenosmilus broke these groupings by possessing both stout muscular legs and body, and short broad upper canines.




Grizzly Bear - Ursus arctos horribilis
The grizzly bear is a large predator that is different from black bears due to a distinctive hump on its shoulders. Grizzly bears have concave faces and long claws about the length of a human finger. Their coloration is usually darkish brown but can vary from very light cream to black. The long guard hairs on their backs and shoulders often have white tips and give the bears a "grizzled" appearance, hence the name "grizzly." The correct scientific name for the species is “brown bear”, but only coastal bears in Alaska and Canada are referred to as such, while inland bears and those found in the lower 48 states are called grizzly bears.
Height 3- 3 ½ feet at shoulders
Length 6-7 feet
Weight Adult males 300 - 850 lbs; females 200 - 450 lbs
Top speed 35 mph



carnivora.net/xenosmilus-hodsonae-v-grizzly-bear-t3370.html

From Carnivora.

[brobear]

prehistoric-fauna.com/Xenosmilus-hodsonae

Xenosmilus hodsonae
7 reviews
Xenosmilus (Xenosmilus Martin et al., 2000)

Order: Carnivora

Family: Felidae

Subfamily: †Machairodontinae

Tribe: †Homotherini

Time period: Pleistocene of North America (The fossils were of Irvingtonian age (1.8 to 0.3 Ma).

Size: 2 m in length, 105 cm in height, 170-300 kg of weight.

A typical representative: Xenosmilus hodsonae

Xenosmilus is a genus of extinct Machairodontinae, or saber-toothed cat. They lived about 1 million years ago, but as there are only two specimens of the same age, when they appeared and when they became extinct is unclear. Currently, there is only one species known, X. hodsonae.

Physically, the cat measured between 1.7–1.8 m long with a highly muscular body, even more muscular than any other cat alive or dead, and the animal probably weighed around 200- 300 kg. Only Smilodon populator was noticeably larger amongst the saber-toothed cats. Before their discovery, all known saber-toothed cats fell into two general categories. Dirk toothed cats had long upper canines and stout legs. Scimitar toothed cats had only mildly elongated canines, and long legs. Xenosmilus broke these groupings by possessing both stout muscular legs and body, and short broad upper canines.

Found alongside the two skeletons were dozens of peccary bones. It seems likely, with their muscular builds, that X. hodsonae preyed upon peccaries in life.

[brobear]

Result of your conversion:
300 kilograms is equal to
661.39 pounds (avoirdupois)

Xenosmilus hodsonae was a really bad-ass cat. I would wager on this cat against Smilodon. Unusual attribute are his big ( not simply long ) teeth designed for grappling. At weight parity against a Pleistocene grizzly, I would give them each a 50-50 ( just an opinion ). I would not wager.
Very unlikely that a grizzly ever met this cat.

[King Kodiak]

The Xenosmilus was very "bear like", He had a very robust skeleton and it seems he was a good grappler. At weight parity, i guess its 50%. 

[brobear]

Dec 22, 2019 12:55:32 GMT -5 King Kodiak said:

The Xenosmilus was very "bear like", He had a very robust skeleton and it seems he was a good grappler. At weight parity, i guess its 50%. 

Even his canine teeth were designed for grappling rather than slicing like other saber-toothed cats. Of course, so are the grizzly's canine teeth, big and deeply rooted.

[OldGreenGrolar]

The grizzly bear’s shoulder hump, denser bones, and shorter backbone should give it greater strength than the Xenosmilus. While, the Xenosmilus does have shorter and more robust limbs than a grizzly bear as well as superior grappling skills compared to other big cats, it still has inferior grappling skills compared to a grizzly bear. That being said, it is a close match with a mature male grizzly bear having a slight advantage at weight parity. I would like to add: If either animal suffers broken jaws, the grizzly bear will still have a much better chance to survive due to its omnivorous diet and might be more willing to engage in a fight in general.

[OldGreenGrolar]

Some info of the Xenismilus:

"Features of the postcranial elements suggest a powerfully built ambush predator capable of grappling with large prey. The scapula (Figure 5) is larger than that of Smilodon and has a hefty, oval-shaped glenoid fossa, suggesting that the shoulder was capable of moving the forelimbs laterally while wrestling prey. The humerus (Figure 6) is narrower than that of Smilodon but possesses some features that are more robust including a larger and more rounded humeral head, and a taller, broader greater humeral tuberosity. Corresponding muscle attachments indicate a wider range of movement in the shoulder joint. The ulna is shorter than the humerus and shorter than in Smilodon. Features on the articular surfaces of humerus, radius, and ulna suggest that Xenosmilus hodsonae was capable of pronating the forearm to a larger degree than other large cats, which would have facilitated its ability to grasp struggling prey and perhaps even climb trees. The radius and hand bones are also curved in such a way to suggest that the animal could exert great force to pull in its prey closer (Martin et al., 2011).

The hindlimbs of Xenosmilus hodsonae also show several specializations for prey capture. The femur (Figure 7) is relatively shorter and more robust than even those of bears or giant panda. Compared to other large cats, the lesser trochanter of the femur was larger, suggesting that the psoas major muscle, which attaches there, was well developed. A more powerful psoas major muscle would have had kept the hips of the animal steady while it reared up on its hind legs while wrestling prey with its forelimbs. The femur also has a relatively wide patellar groove, which supported a relatively large patella (Figure 8). This indicates that Xenosmilus hodsonae had large quadriceps muscles which stabilized the knee during prey capture. However, the femoral condyles of Xenosmilus hodsonae protrude further posteriorly than other large cats, suggesting that this animal also had more flexible knees, which would have been useful while stooping down to ambush prey. Furthermore, features on the tibia and ankle bones suggest that Xenosmilus hodsonae held its foot in a plantigrade position, similar to bears (Martin et al., 2011)."

This lion sized cat (Xenosmilus) was in many areas more robust than Smilodon and Bears, with a greater grappling ability than other cats.

carnivora.net/xenosmilus-hodsonae-v-grizzly-bear-t3370-s70.html

Credited to Taipan.


For now, simply a few of the indexes from the article "Postcranial Morphology and the Locomotor Habits of Living and Extinct Carnivorans" by Samuels et al (2013).
Readers can use this thread as a reference.

Index: Xenosmilus hodsonae - Ursus arctos
Brachial index: 0.7184 - 0.8984
Humeral robustness index: 0.0985 - 0.1081
Humeral epicondylar index: 0.2954 - 0.2997
Crural index: 0.7817 - 0.7572
Femoral robustness index: 0.0984 - 0.0747
Femoral epicondylar index: 0.2295 - 0.21
Tibial robustness index: 0.1048 - 0.0884
Pes length index: 0.2691 - 0.2141
Intermembral index: 0.9583 - 0.9167

I wouldn't say this points strongly in either direction.


carnivora.net/xenosmilus-hodsonae-v-grizzly-bear-t3370-s67.html

Credited to Taipan.

[OldGreenGrolar]

More info on the Xenosmilus:




books.google.com.mx/books?id=2GjhrKO9y74C&pg=PA43&lpg=PA43&dq=The+osteology+of+a+cookie-cutter+cat,+Xenosmilus+hodsonae.&source=bl&ots=7R4GrOfKZ3&sig=MKqMU_zHf1lcFH2T1ek7tyo1VAU&hl=en&sa=X&redir_esc=y#v=onepage&q=the%20skull%20is%20about%20the%20size%20of%20that%20of%20a%20small%20african%20lion&f=false

The general plan of the skull of Xenosmilus hodsonae is narrow and small in comparison to body size. The size of the skull is about as big as that of a small lion (Panthera leo) or a small individual of Smilodon fatalis, although its body size closer to the size of an average lion (Martin et al., 2011). The muzzle is shorter than in the genera Panthera and Smilodon with considerably narrow frontals and zygomatic arches displaying limited lateral flare (Figure 3). The cranium of Xenosmilus hodsonae is also characterized by a diminuitive postorbital process, large occipital condyles, and a relatively large mastoid process compared to the genus Homotherium. In addition, the mandibles of Xenosmilus hodsonae (Figure 4) have a smaller flange compared to Homotherium.

www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/xenosmilus-hodsonae

carnivora.net/xenosmilus-hodsonae-v-grizzly-bear-t3370-s68.html

Credited to Rorqual.

[brobear]

Xenosmilus was about the size of a lion but more heavily built. Roughly the size of Smilodon fatalis with an upper max weight of about 600 pounds. A more common weight likely around 400 pounds. These cats were probably extinct before the grizzly migrated down south of Canada. But if they were there, a grizzly could likely have displaced this big cat from a carcass. The Pleistocene grizzly *probably averaged near 700 pounds.

[OldGreenGrolar]

The Xenosmilus might be bulkier than other big cats but if it is lion size, even an extant male grizzly bear would beat it.

[brobear]

From the first post on this topic - quote: "...Physically, the cat measured between 1.7-1.8 m long with a highly muscular body, even more muscular than any other cat alive or dead, and the animal probably weighed around 230-400 kg."

*1.8 meters is equal to 5.91 feet or 5 feet 10.92 inches ( just under 6 feet long ). A grizzly of this length would weigh about 226.80 kg or 500 pounds - tops. I seriously doubt that any cat would weigh more than a grizzly at equal head-and-body length. 
 
              

[OldGreenGrolar]

From the size comparison, the grizzly bear is bulkier hence it has more powerful forearms.

[theundertaker45]

I remember reading through a post on WildFact where an experienced user guessed the Xenosmilus' average weight as being anywhere between ~220-240kg; another work I came across at Carnivora determined an average weight range of 180-230kg This matchup would pretty much be at weight parity then with both of them averaging 450-465lbs. 

[theundertaker45]

The weight of Xenosmilus was often overestimated in the past, some even claimed it was close to Smilodon populator in size, however, this isn't the case. Xenosmilus had the overall body measurements of a male lion being a bit shorter in terms of body length. Despite its skull looking pretty fearsome it was also rather small on the other hand being ~330-335mm in greatest length; therefore comparable to the skull size of our modern Indochinese tiger.

Here are some morphological indexes comparing the brown bear (right number) with Xenosmilus hodsonae (left number):

Brachial index: 0.7184 - 0.8984
Humeral robustness index: 0.0985 - 0.1081
Humeral epicondylar index: 0.2954 - 0.2997
Crural index: 0.7817 - 0.7572
Femoral robustness index: 0.0984 - 0.0747
Femoral epicondylar index: 0.2295 - 0.21
Tibial robustness index: 0.1048 - 0.0884
Pes length index: 0.2691 - 0.2141
Intermembral index: 0.9583 - 0.9167

While the grizzly bear would most likely possess the more robust and stronger forearms, the Xenosmilus had extremely stout legs which may have helped in keeping the hips steady while rearing up on its hind legs. Apart from that, Xenosmilus was described to be a plantigrade creature. The big question would be if the more robust hindlegs of the Xenosmilus could help him overcome the more robust/stronger forearms of the brown bear by providing additional stabilizing features during a grapple.

[brobear]

This description makes in sound like Xenosmilus was perhaps the most bear-like of all the cats. Robust and plantigrade.   
 
*With this "new-to-me" information, I would give this face-off a 50-50. Against a Russian black grizzly, perhaps about 7 or 8 out of 10 for the bigger bear.

[OldGreenGrolar]

The Xenosmilus actually has greater grappling abilities than even the smilodon populator.

[brobear]

May 11, 2020 6:43:53 GMT -5 OldGreenGrolar said:

The Xenosmilus actually has greater grappling abilities than even the smilodon populator.

IF Xeno... could manage to position his jaws onto the grizzly's neck, the ballgame is over.
               

[OldGreenGrolar]

Biting the neck in a face to face fight is not going to be easy especially if the opponent is fighting back. A male grizzly or Ussuri brown bear which does not climb trees is more likely to fight back.

[King Kodiak]

Humeral robustness index: 0.0985 - 0.1081

The grizzly bear (right score) has just a slightly more robust Humerus than the Xenosmilus. 

In the study posted by TheUndertaker, Xenosmilus had the most robust Humerus of all cats (Populator and Atrox were not included on that section)

domainofthebears.proboards.com/post/38365/thread

It seems that at average these two are very close to weight parity. For now, i still think its 50%.

[brobear]

Quote from reply#13 by theundertaker45

"Xenosmilus had the overall body measurements of a male lion being a bit shorter in terms of body length."
This would put Xenosmilus into the same size-range as Smilodon fatalis.