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Smilodon populator
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Smilodon populator

[Image: f44cf72d5f4bd1c12e0e2ee27d346680.jpg]

Temporal range: Late Pleistocene, 1.0 –.01 Ma

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Subfamily: Machairodontinae
Genus: Smilodon
Species: Smilodon populator

Smilodon populator was one of the biggest cats of all time. It was the largest of the saber-tooths, and lived in South America during the Late Pleistocene: about two million to 10,000 years ago. It originally evolved from ancestors that invaded the continent North America about three million years ago. 

[Image: rushelle-kucala-smilodonskeletonlabels.jpg?1459289906]

Physical Description
With an estimated weight of 200 to 300 kg and exceptional large specimens probably up to and over 400 kg, it was among the heaviest felids to have ever existed. It was much larger than its relatives, S. fatalis and S. gracilis, possessing a massive chest and front legs, and is the largest known variety of saber-toothed cat. It was more than 1.40 m (55 in) high at the shoulder, 2.6 m (100 in) long on average and had a 30 cm (12 in) tail. With an estimated weight of 360 to 470 kg (790 to 1,000 lb), it was among the heaviest known felids. Its upper canines reached 30 cm (12 in) and protruded up to 17 cm (6.7 in) out of the upper jaw. Genetic evidence suggests Smilodon populator and other members of the genus diverged from the main lineage of modern cats (subfamily Felinae) around 14-18 million years ago.

S. populator, had higher shoulders than hips and a back that sloped downwards, superficially recalling the shape of a hyena, in contrast to the level-backed appearance of S. fatalis, which was more like that of modern cats. However, while its front limbs were relatively long, their proportions were extremely robust and the forearm was shorter relative to the upper arm bone than in modern big cats, and proportionally even shorter than in S. fatalis. This indicates these front limbs were designed for power rather than fast running, and that S. populator would have had immense strength in its forequarters.

[Image: smilodon-web-new-use-1280x1071.jpg]

Despite being more powerfully built than other large cats, Smilodon actually had a weaker bite. Modern big cats have more pronounced zygomatic arches, while Smilodon had smaller zygomatic arches which restricted the thickness and therefore power of the temporalis muscles, and thus reduced Smilodon’s bite force. Analysis of its narrow jaws indicates it could produce a bite only a third as strong as that of a lion. There seems to a be a general rule that the saber-toothed cats with the largest canines had proportionally weaker bites. However, analyses of canine bending strength (the ability of the canine teeth to resist bending forces without breaking) and bite forces indicate the saber-toothed cats' teeth were stronger relative to the bite force than those of modern "big cats". In addition, Smilodon could open its jaws 120 degrees, whereas the lion's gape is limited to 60 degrees.

Smilodon populator is also known from the famous cave site of Ultima Esperanza, with well-preserved remains retaining endogenous DNA.


Predatory Behaviour
The saber-tooths were specialist predators that fed on large-bodied prey. It has been an enduring mystery as to how Smilodon used its huge teeth when hunting. Some scientists think that it would slash at prey, causing huge wounds. A more likely theory suggests that the sabers evolved for a neck death-bite. In this scenario, Smilodon would hold down its struggling prey with its huge arms while it gripped the animal's throat with its mouth, the sabers slashing through arteries and crushing the windpipe. Prey quickly would be killed in this fashion, making it less likely the Smilodon would be injured. 

Behaviour
The social pattern of this cat is unknown. Some fossils show healed injuries or diseases that would have crippled the animal. Some palaeontologists see this as evidence that saber-toothed cats were social animals, living and hunting in packs that provided food for old and sick members. Living in groups would also help with having to compete with lions and wolves. The canine teeth and body size of Smilodon were about the same in both male and female cats. This indicates that Smilodon may not have lived in male-dominated groups (and that the teeth may not have been used for attracting mates as it has been suggested). However, it still could have hunted cooperatively.

Extinction
The extinction of most large-bodied herbivores 10,000 years ago meant that Smilodon had lost all of its favorite prey. Unable to compete with small-prey specialists like the cougar, the saber-tooths became extinct about 10,000 years ago and left no descendents.
[Image: wildcat10-CougarHuntingDeer.jpg]
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  • Claudiu Constantin Nicolaescu
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Taipan Wrote:
reddhole Wrote:
Source: Per Christiansen and John M. Harris, "Body Size of Smilodon", Journal of Morphology: 266: P 369-384, 2005


Here is the abstract:

ABSTRACT The body masses of the three large sabertoothed
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.


Below is a discussion of the weight ranges of the Smilodon species:

The included specimens of Smilodon, although
showing some size-variation and including large
specimens, are not among the largest known (see,
e.g., Merriam and Stock, 1932; Kurte´n and Werdelin,
1990). Accordingly, the extreme upper size
ranges of Smilodon are probably not represented in
the current study and, since unusually large specimens
in extant mammals are always rare, it is unlikely
that such specimens will ever be found in the
fossil record. Among extant mammals, at least the
larger species, some unusually large specimens significantly
exceed the upper size range of normal
individuals (see, e.g., Wood, 1976; Nowak, 1991;
Christiansen, 1999a, 2004), a pattern also present in
felids (Sunquist and Sunquist, 2002).

Although males of both lions and tigers exceeding
300 kg in body mass have been shot (Wood, 1976;
Sunquist and Sunquist, 2002), this is well outside
the normal size range of even very large males (Fig.
5), and adult Siberian tiger males usually range
from 220–260 kg (Sunquist and Sunquist, 2002), in
accord with the sizes of the three specimens used in
the present analysis (Table 1; Appendix A). Accordingly,
unusually large specimens of Smilodon may
well have significantly exceeded the body mass
ranges reported here also. Accordingly, S. gracilis
almost certainly, on occasion, exceeded 130 kg (Fig.
5), as in extant jaguars (Nowak, 1991; Sunquist and
Sunquist, 2002). Particularly large S. fatalis males
may well have reached a body mass of around 350 kg
(Fig. 5), if not more, but unlike Anyonge (1993), we
suggest that this value is best regarded as an outlier
to the normal size range of this species.


Smilodon populator is clearly one of the largest
felids ever discovered, rivaled only by the giant
Pleistocene North American lion (Panthera atrox;
see Merriam and Stock, 1932; Anyonge, 1993;
Turner and Anton, 1997), and even normal-sized
individuals are predicted to have rivaled world
record Siberian tiger males (see Wood, 1976; Nowak,
1991; Sunquist and Sunquist, 2002). There is every
reason to suppose that unusually large S. populator
males exceeded 400 kg in body mass, perhaps significantly
so. This would effectively remove S. populator
from the size distribution of extant felids (Fig.
5).


Here is a comparison of the normal weight ranges and the weights of exceptionally large individuals of extant big cats and the the three Smilodon species:

[Image: SmilodonBigCatWeights002.jpg]

taipan Wrote:Smilodon Populator was a lion-sized cat, extremely strong and powerful (particularly in the chest and forelimbs; an adaptation designed for its large-sized prey) and armed with 7-inch long sabre-teeth. Some debate has taken place on exactly how these were used. Some people suggested they were for climbing trees, others for punching through the skull of the prey, and still others claimed they were used to stab into the throats of the herbivores. Calculations indicated that the teeth were not strong enough for the first two applications - they would have shattered when they impacted bone, and this also ruled out the neck-bite technique used by the extant small cats. The 'stab' theory didn't hold water, either, as the cat's neck and jaw muscles were not powerful enough to propel the teeth through the thick hide.

The rear edges of the sabres are serrated, and this indicated that the cat used its teeth as blades to cut through the hide and tissues of its prey, rather than as daggers. The smaller lower canines were driven into the hide of the prey animal's neck or belly, to provide purchase for a downward strike by the sabres as the cat closed its jaws (this action is termed a 'shearing bite'). Evidence for this is the fact that Smilodon's jaws could open 25 degrees wider than those of the modern cats, allowing it to achieve a similar clearance between the tips of upper and lower canines as modern cats. By using this technique, the teeth would never encounter bone. The prey animal would then die of blood-loss. The problem with this explanation is that any torsional loads on the teeth, for example the movements of a standing prey animal, would break them. So Smilodon could not have brought down its prey using its teeth alone. It is probable that hunting took place in groups, and the upper-body strength of the cats was used to capture and restrain the prey before the fatal bite was applied to the throat. 

One of the advantages of the sabre was that prey carcasses could be sliced up and carried back to the den to feed young, eliminating the need for the young cubs to accompany their mother. There is some evidence that Smilodon may have lived in a pride social structure. The Rancho La Brea asphalt pit fossils indicate that for every trapped herbivore, several Smilodon are present, leaving pack-hunting a likely scenario. In addition, the Sabres' teeth were so large that they did not fully develop until the animal was quite mature, so the level of maternal care required over a long period would have been high. This would suggest social groupings were the norm.

Smilodon Populator lived in the east of South America, and other (slightly smaller) species of Smilodon lived in North America. Its body was in some ways different from the lion; relatively, it had shorter hind- and longer fore-limbs, giving it a stance more like that of a hyaena. This would have allowed it to run more easily, and so chase prey over long distances. In contrast, the modern lion will not usually sustain a chase beyond a few hundred metres.

The Sabre-tooth design was predominant among the cats until 5-6 Ma, when climate change resulted in the forests which had covered the continents giving way to open savannah and plains. This in turn led to the proliferation of smaller herbivores, such as antelope and gazelle, which could outrun the Sabre-toothed cats easily. It was at this point that the Pantherines evolved, from which descended many of the larger cats of today, with smaller teeth and other adaptations to the new prey species.

The Sabre toothed cats were still able to survive, as the mega-herbivores were still in existence, but around 35,000 years ago further climate change led to colder weather. This saw the demise of the mega herbivores, and so the sabre-toothed cats. The evolution of hominids, who hunted with weapons, and competition from pantherine species such as the lion (which evolved only 600,000 years ago) lead to their final downfall.
http://www.lioncentral.com/sabre.html

Taipan Wrote:Saber-toothed Cats Wrestled Prey with Powerful Arms

By Charles Q. Choi, LiveScience Contributor
posted: 02 July 2010 04:59 pm ET

Saber-toothed cats might be most famous for their oversized fangs, but scientists now find the feisty felines had another exceptional feature — powerful arms stronger than those of any cat alive today. 

Commonly known as the "saber-toothed tiger," the extinct cat Smilodon fatalis roamed the Americas until roughly 10,000 years ago, preying on "megafauna" — large animals such as mammoths, bison, camels and mastodons. Their specialization on such giant creatures might have doomed these hunters when their Ice Age prey died off. 

The most recognizable features of the saber-toothed cat — giant, dagger-like canines — were also perhaps its most puzzling. The fangs would have been excellent at inflicting deadly slashing bites to its prey's throat, but their size and shape would also have made them highly vulnerable to fracturing compared with modern cats. That led researchers to wonder how the fangs developed in the first place. 

Cat teeth 

"Cats living today have canines that are round in cross-section, so they can withstand forces in all directions," said researcher Julie Meachen-Samuels, a paleontologist at the National Evolutionary Synthesis Center in Durham, N.C. "If the prey is struggling it doesn't matter which way it's pulling — their teeth are unlikely to break." 

In contrast, the long canines of saber-toothed cats were oval in cross-section, or thinner side-to-side, making them relatively fragile. This suggested that saber-toothed cats must have killed prey differently from other cats. In fact, research published in 2007 suggested Smilodon had a wimpy bite. 

That's where the powerful arms come in. These predators might have pinned victims down with their heavily muscled forelimbs to protect their teeth from fracturing as they bit struggling prey, Meachen-Samuels said. 

Feline wrestling match 

In an arm-wrestling match of sorts, the researchers compared saber-tooth arms with those of other cats. To do so, they X-rayed the arm and leg bones of fossils recovered from the La Brea Tar Pits in Los Angeles. They also analyzed the limb bones of 28 cat species living today — ranging in size from the 6-pound (2.7-kilogram) margay to the 600-pound (272-kg) tiger — as well as the extinct American lion, the largest cat with conical teeth that ever lived. These measurements helped the researchers estimate bone length, rigidity and strength for each species. 

Species with longer limbs generally had stronger bones. However, while saber-tooth leg bones fell within the normal range, their arm bones were exceptionally thick for their length. Not only that, their arms also had thicker cortical bone — the dense outer layer that makes bones strong and stiff. 

"When I looked at Smilodon, I knew they were thicker on the outside than other cats, but I was really shocked at how much thicker they were on the inside as well," Meachen-Samuels told LiveScience. 

The thicker cortical bone seen with the saber-toothed cats makes sense if the arms were under greater stress than normally expected for cats their size, Meachen-Samuels explained. Just as lifting weights improves bone density over time, so too may the repeated strain of grappling with prey have resulted in thicker and stronger arm bones in saber-toothed cats. 

"As muscles pull on bones, bones respond by getting stronger," Meachen-Samuels said. "Because saber-toothed cats had thicker arm bones, we think they must have used their forelimbs more than other cats did." 

The researchers would like to next look at other saber-toothed cats, as well as other saber-toothed predators that once existed. "There aren't a lot of arm bones to X-ray for other saber-toothed predators, but it'd be interesting to see if there were convergent processes with their arms as well," Meachen-Samuels said. 

Meachen-Samuels and her colleague Blaire Van Valkenburgh detailed their findings online July 2 in PLoS ONE.

http://www.livescience.com/animals/saber...00702.html

Taipan Wrote:How a Smilodon sabretooth cat closed its gaping mouth  

By Victoria Gill 
Science and nature reporter, BBC News  
Page last updated at 12:14 GMT, Friday, 25 February 2011

[Image: _51410091_000223914-1.jpg] 
The sabretoothed cats killed prey with a deep stabbing bite to the throat
  
The mystery of how prehistoric sabretoothed cats coped with their oversized teeth has been solved in part by a new analysis of the cats' jaws.

To impale prey with these impressive weapons, the famous sabretoothed cats must have opened their mouths wider than any modern big cat, but it was unclear if their jaw muscles were strong enough to do it. 

Now the new analysis reveals that the cats' jaw muscles evolved into a specialised pattern, which allowed them to open their mouths so wide. 

Details are reported in the Zoological Journal of the Linnean Society. 

Weak bite?

Per Christiansen, from Aalborg University in Denmark, led the study. He took a novel approach to studying the extinct predators by creating a complex model of how their jaws moved.

Beautifully preserved skeletons of the most recently extinct sabretoothed cat, Smilodon, have been uncovered in tar pits in the US, offering the researcher plenty of fossilised remains to work with. 

These fearsome-looking cats - the biggest of which would have hunted very large prey, including buffaloes, horses and extinct giant ground sloths - had a relatively weak bite force compared to their modern feline relatives, previous studies have revealed. 

But this is not surprising, according to Dr Christiansen. He has found the cats must have had remarkable jaw muscles to close their mouths with any force at all. 

"Smilodon could open its mouth wider than any modern cat," explained Dr Christiansen, "because if you have big teeth, you have to open your mouth at a very high angle to get anything in your mouth." 

Fatal stabs

[Image: _51413259_sabrebite1_cleanedit.jpg] 
Smilodon (right) was able to open its mouth wider than any modern cat

Over the years, scientists have debated what the now extinct cats used their enormous teeth for, with some even suggesting the teeth were ornaments that males used to attract mates. 

But the consensus is now that the teeth, which measured up to 20cm, delivered final, fatal stabs to already subdued prey. 

Bulkier and more muscular than most modern cats, Smilodon would have brought large animals down with its forelimbs. 

"They pounced on their prey, wrestled it to the ground and twisted the neck with massive forelimbs," explained Dr Christiansen. 

"They then delivered a quick, powerful and deep stabbing bite to the throat or upper neck. But, there were no minute-long massive asphyxiating throat-clamps like those used by modern big cats when they suffocate prey. The sabrecats simply didn't have the jaw muscles for that." 

Opening their mouths sufficiently wide to kill and consume their hard-earned meal would have stretched and significantly weakened their jaw muscles.

Dr Christiansen created a model of the cats' jaws, carefully calculating how they must have moved, to work out how Smilodon evolved to compensate for this weakness. 

His model revealed how the cats' jaw muscles were aligned to pull its jaws closed, very directly and efficiently. 

But Smilodon would also have done something that every cat-owner can see a relic of in their own pet. 

"When you put a piece of food on the floor for your cat, you'll see it bobs its head forward as it eats it," he explained. 

"And we know that [Smilodon] probably closed its jaws by twisting its head downward and throwing its head forward. 

"Its neck was longer than that of modern cats and its neck muscles would have been stronger." 

'Killing ecology'

The study also looked back at the earliest and most primitive sabretoothed animals. 

"Smilodon was outrageous in terms of its anatomy," said Dr Christiansen. 

"It was the most [highly evolved and therefore] different from modern cats, so to understand this animal from a biological sense, you need to study more primitive animals to work out why they have become that way through evolution."

[Image: _51414139_c0048072-spl.jpg] 
Smilodon would have brought down prey with its powerful forelimbs

He examined hundreds of skulls, drawing an evolutionary map showing why sabretooths evolved such different jaw anatomy from modern cats. 

"Killing ecology", he explained, was the driving factor - the evolutionary pressure to kill prey with a deep and efficient stab to the throat. 

"The cat species became gradually more and more specialised, culminating with monsters such as Smilodon," said Dr Christiansen. 

As sabretooths evolved longer canine teeth, their jaw muscles actually grew smaller, but the fibres became more vertically orientated and thus probably more efficient in closing the jaw.

Dr Christiansen explained: "At the same time, changes in the way the muscle fibres inserted on the lower jaw meant that the animals could stretch their muscles more - the fibres became re-orientated so as to allow a higher gape, necessary for gaping with huge fangs." 

But their impressive appearance might well have been key to their demise; the sabre-toothed cats were dependent on large, relatively slow-moving prey. 

"They had very powerful but heavy bodies and rather short, extremely powerful legs," said Dr Christiansen, "so they probably weren't very fast, and certainly nowhere near as fast and agile as leopard and tigers."
 
http://news.bbc.co.uk/earth/hi/earth_new...399605.stm

Red Dog Wrote:
Quote:From Taipan/Reddhole: Source: Therrien; "Mandibular Profiles of Extant Carnivores and Implications for the Feeding Behavior of Extinct Predators"; Journal of Zoology: 267: P 249-270; 2005

 However, Anyonge (1996)
has shown that the cross-sectional geometric properties
(i.e. bending strength) of the limbs of Panthera atrox,
particularly of the humerus, were much greater than
those of the extant lion, being closer to those of the
brown bear, Ursus arctos. In other words, the extinct
lion had much stronger forelimbs than an extant lion
of similar body size.
Therefore, large prey could have
been primarily subdued and restrained by the extremely
powerful forelimbs of Panthera atrox, which would have
greatly reduced stresses on the mandible during the
canine bite. [/size]
From Reddhole:

Below is a relevant graph and analysis from Anyonge's referenced study above. This graph illustrates locomotor adaptions and animals toward the right are more adapted for cursoriality and animals toward the left are more adapted for grappling. Coursers include wolves, hyenas, and cheetahs. Ambushers are big cats, and ambulators are bears.

[Image: AnyongeLocomotorGraph001.jpg]

Here is a discussion. Function 1 (the horizontal axis) is the more important of the two functions. The weights of the variables impacting this are listed in the table below (ignore the signs, the absolute value of the variables are how much they impact the results).

[Image: AnyongeLocomotorDiscussion001.jpg]

[Image: AnyongeLocomotorDiscussion002.jpg]

Overall, Smilodon Fatalis appears more adapted for grappling than Panthera Atrox. Smilodon Populator was more specialized than Smilodon Fatlis and would likely score even higher.

Red Dog Wrote:From Reddhole:

Smilodon fatalis killed conspecifics with bites to the skull or ribs.

Smilodon may have used a careful canine shear bite to the throat with huge prey, such as the ice-age bison (larger than the modern species), but apparently it could bite the skull ot ribs of other smilodons.

Quote:IMHO, the fragility of Smilodon's canine teeth is overstated. While it is true that Smildon killed ice-age megafauna (i.e. ~ 3,000 lb. Pleistociene bison) with a careful and precise canine-shear bite, similar-sized predators were (at least sometimes) killed with bites to the skulls or ribs. The following extract is from this study:

Source: Per Christiansen, "Comparitive Bite Force and Canine Bending Strength in Feline and Sabertooth Felids: Implications for Predator Ecology", Zoological Journal of the Linnean Society, 151: 2, 2007, P 423-437

Note the following statement:


Smilodon may generally have avoided biting directly into bone during hunting, but direct evidence exists of it being an aggressive predator with a bite powerful enough to drive canines through bone, such as another Smilodon skull with a deep bite wound, or a rib cage with a canine tip still embedded in it.


[Image: SabertoothKillingTechnique001.jpg]
[Image: SabertoothKillingTechnique002.jpg]

This is also supported by this study's measurements of the sabertooth's canine bending strength. S AP and S LM are different measurement of canine strength. Smilodon fatalis's canines were similar (and in some respects greater) in strength as lions, tigers and jaguars, but the sabertooth cat was also heavier.

[Image: SmilodonBigCatBiteForce001.jpg]

IMHO, Smilodon could have also dispatched a similar sized carnivore with a canine shear bite to the throat as well. All cats have to be somewhat careful when they bite, and must have decent control over their adversary before making a killing bite. The extra control a Smilodon would require could easily be met by its vastly superior strength.

Red Dog Wrote:Source: Prevosti, F.J. and Vizcaíno, S.F. 2006. Paleoecology of the large carnivore guild from the late Pleistocene of Argentina.
Acta Palaeontologica Polonica 51 (3): 407–422.


The size and morphology of Smilodon populator indicate that
it preyed habitually on middle−sized mammals such as large
armadillos, equids, small glyptodonts (e.g., Sclerocalyptus
migoyanus), and large camelids, but it would also be able to
hunt megamammals weighing approximately 1000 to 2000
kg, as well as juveniles of the larger species (i.e., Megatherium
americanum Cuvier, 1796).


http://app.pan.pl/archive/published/app51/app51-407.pdf

Taipan Wrote:Saber-toothed cats hunted on the South American plains

Date: March 18, 2016
Source: University of Tübingen

[Image: 160318090432_1_900x600.jpg]
Canine tooth of a saber-toothed cat.
Credit: Hervé Bocherens

Like the lion which today lives in the African savannah, the saber-tooth "tiger," Smilodon populator, inhabited the open, dry country found in South America during the ice age, according to Professor Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tübingen. The results of his latest study have been published in the latest edition of the journal Palaeogeography, Palaeoclimatology, Palaeoecology. To find out more about the eating habits of what was then South America's biggest cat, Bocherens and his team examined the bones of saber-toothed cats which lived in Argentina's Pampas region in the period 25,000-10,000 B.C.

"Up to now, palaeontologists assumed that a predator weighing up to 400 kilograms and with bone structure similar to that of a forest-dwelling cat would have hunted in woodlands," says Hervé Bocherens. It was thought that would make it easier for the animals -- with their canines up to 30 centimeters long -- to find hiding places from which to attack their prey. But Bocherens' study points to a different conclusion. He compared collagen samples from the bones of various ice age predators -- including the saber-toothed cat, the jaguar (Panthera onca), and a species of wild dog (Protocyon) -- with those of their likely prey. The carbon and nitrogen isotopes he found there enable him to draw conclusions about the kind of environment the animals lived in.

The saber-toothed cats did not eat animals which were at home in thickly wooded country. Their chief prey seems to have been a camel-like, steppe-dwelling ungulate known to scientists as Macrauchenia, and two species of giant sloth (Megatherium und Lestodon) -- who, unlike their surviving relatives, lived on the ground and could grow to several tonnes in weight. There could be a further parallel with today's African lions; the bones of several individual saber-toothed tigers were found together and contained similar isotopes, Bocherens says -- "It may be that these predators, too, hunted together in groups."

The saber-toothed cat (Smilodon) evolved in North America and spread to South America with the formation of a stable land bridge between the two continents some three million years ago. It appears that the saber-toothed tigers' fiercest competitors were not other big cats. The study indicates that the jaguar preferred smaller prey, such as rodents and species of horse. But the ice age dog (Protocyon) seems to have shared the saber-tooths' culinary tastes.

Many types of megafauna died out at the end of the ice age, including the saber-toothed cat. Researchers debate the possible influence of climate change and human activity on the extinctions. The Tübingen researchers believe that a damper climate could have led to increased forestation of the steppe -- reducing the saber-toothed tigers' hunting grounds and ultimately causing them to die out.

Story Source: University of Tübingen. "Saber-toothed cats hunted on the South American plains." ScienceDaily. www.sciencedaily.com/releases/2016/03/160318090432.htm (accessed March 18, 2016).



Journal Reference:
Hervé Bocherens, Martin Cotte, Ricardo Bonini, Daniel Scian, Pablo Straccia, Leopoldo Soibelzon, Francisco J. Prevosti. Paleobiology of sabretooth cat Smilodon populator in the Pampean Region (Buenos Aires Province, Argentina) around the Last Glacial Maximum: Insights from carbon and nitrogen stable isotopes in bone collagen. Palaeogeography, Palaeoclimatology, Palaeoecology, 2016; DOI: 10.1016/j.palaeo.2016.02.017

Highlights
• The sabretooth cat Smilodon populator was the largest felid in South America.
• First δ13C and δ15N for Smilodon from 25 to 10 kyr BP in the Pampas
• Predator of large prey from open landscape (Macrauchenia, giant ground sloths)
• Smilodon was possibly competing with the large canid Protocyon but not with the jaguar.
• Holocene climate change may have contributed to its extinction.

Abstract
The sabretooth cat Smilodon populator was the largest felid in South America. It appears in the fossil record in the Early Pleistocene, as an immigrant from North America, and becomes extinct around the Pleistocene–Holocene boundary. The carbon and nitrogen stable isotopic values of collagen were measured for skeletal remains from Smilodon specimens ranging in age from 25 to 10 kyr BP, for the first time in the Pampas region of Argentina. By comparison with similar values obtained on co-eval predators such as Protocyon (large canid) and Panthera onca (jaguar) and a range of potential prey, such as giant ground sloths, glyptodontids, Macrauchenia, Toxodon, equids, cervids, and rodents, it could be established that Smilodon consumed essentially large prey from open landscape, such as Macrauchenia and giant ground sloths during the last 15,000 years of the Late Pleistocene in the Pampa region. It was possibly competing with the large canid Protocyon but the jaguar was apparently feeding on smaller size prey. A more humid climate at the beginning of the Holocene might have been unfavorable to this large predator and could have contributed to its extinction. These results also provide an important insight to understand the ecological processes involved in the Great American Biotic Interchange.

[Image: 1-s2.0-S0031018216000912-fx1.jpg]
Predators: Jaguar, [i]S. populator, Protocyon
Prey: includes giant ground sloths, glyptodontids, Macrauchenia, Toxodon, equids, cervids, and rodents[/i]

http://www.sciencedirect.com/science/art...8216000912
[Image: wildcat10-CougarHuntingDeer.jpg]
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https://noticiasmercedinas.com/site/2019...42w48oR_10

Very interesting article about Smilodon Populator piercing skulls during fights
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#4
And in English...

Fossils reveal saber-toothed cats may have pierced rivals’ skulls

The curved canine of one ancient cat fits precisely into a hole left in the skull of another
BY 
JOHN PICKRELL 
7:00AM, MAY 31, 2019


[Image: 052819_jp_smilodon_feat.jpg]
BIG BITE The juxtaposition of these two fossil skulls shows how a large, curving canine tooth from one saber-toothed cat (Smilodon populator) neatly fits in the fossil skull of another member of the same species. 

Saber-toothed cats may sometimes have wielded their formidable canine teeth as deadly weapons to puncture the skulls of rival cats.
It was already suspected that Smilodon cats used their huge canines to take down prey, perhaps by ripping out the prey’s throat (SN: 3/30/19, p. 20). But some researchers argued that the daggerlike teeth, which could grow up to 28 centimeters long in the largest species, were too thin and fragile to puncture bone without breaking. 
But a new analysis of two skulls from Smilodon populator, a saber-toothed cat species that prowled what is now South America, contests that idea, says a team of Argentinian researchers led by Nicolás Chimento. Large puncture holes in the top of the fossil skulls match the size and shape of canines of saber-toothed cats, the researchers report online in the May Comptes Rendus Palevol. Similar injuries are sometimes seen in the skulls of living cats, such as leopards, jaguars and cheetahs, the authors write.
Smilodon canines were strong enough to penetrate bone and were formidable hunting weapons,” says Chimento, a paleontologist at the Bernardino Rivadavia Argentine Natural Science Museum in Buenos Aires. The skull wounds were probably made during tussles while “fighting for territoriality, access to females or food.”
The punctured skulls, dating from the Late Pleistocene Epoch, sometime between 11,000 and 126,000 years, were discovered in northeastern Argentina. An amateur collector found one in 1992, while coauthor Javier Ochoa, a paleontologist at the Florentino Ameghino Regional Museum in Córdoba, found the other. It’s likely that North America’s closely related S. fatalis would have exhibited similar behavior, Chimento says.


Citations
N.R. Chimento et alEvidence of intraspecific agonistic interactions in Smilodon populator (Carnivora, Felidae)Comptes Rendus Palevol. Published online May 2019. doi: 10.1016/j.crpv.2019.02.006


Further Reading
J. Pickrell. Saber-toothed cats were fierce and family-oriented.Science News. Vol. 195, March 30, 2019, p. 20
L. Evans-Ogden. Surgeon aims to diagnose deformities of extinct saber-toothed catsScience News. Vol. 192. October 28, 2017, p. 5. 
S. Zielinski. How a saber-toothed cat is like a can opener. Science News Online. October 6, 2014.
G. Dickey. Saber-toothed cats strong-armed preyScience News. Vol. 178. July, 21, 2010, p. 16.
S. Perkins. A more fearsome saber-toothed cat. Science News Online. October 20, 2008.


https://www.sciencenews.org/article/foss...lls?tgt=nr
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#5
^ That is an important find for discussions involving Smilodon's in matchups. Here's another picture and the abstract.

[Image: 5cf51770ec42f.jpg]
Detail of the injury of Smilodon populator specimen MCA 2046. B. Detail showing the canine of another Smilodon specimen inserted through the opened injury. C. Detail of the injury of specimen MRFA-PV-0564. Not to scale. Credit: Comptes Rendus Palevol (2019). DOI: 10.1016/j.crpv.2019.02.006

Journal Reference:
 Nicolás R. Chimento et al. Evidence of intraspecific agonistic interactions in Smilodon populator (Carnivora, Felidae), Comptes Rendus Palevol (2019). DOI: 10.1016/j.crpv.2019.02.006

Abstract
The saber-toothed cat Smilodon is a characteristic genus of the Pleistocene faunas of the American continent. Smilodon belongs to an extinct clade of felids that had hypertrophied blade-like upper canines. Because the length of the canines is so extreme, the killing bite of Smilodon is a hotly debated topic in vertebrate paleontology. Some authors have proposed that saber-toothed cats had a weak bite and their canines were fragile, not useful for attacking prey or penetrating bones. The aim of the present contribution is to describe two new specimens of Smilodon populator that have injuries on their skulls. Although it cannot be ruled out that the injuries were caused by a potential prey kicking the skull, the size, shape and general features of the injuries suggest that they were inflicted by the upper canines of another Smilodon individual during agonistic interactions.

https://www.sciencedirect.com/science/ar...via%3Dihub
[Image: wildcat10-CougarHuntingDeer.jpg]
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