|
Post by brobear on Dec 5, 2018 18:45:45 GMT -5
Until most recent times, when men extirpated most large dangerous animals, average sizes were generally larger, for big cats and bears, too. The head veteraniarian of Kenya recorded a large wild lion he'd shot as a public menace, weighing it at 272kg, and its skeletal remains, (with official data record) can be seen at the museum in Nairobi. Lions which can live on large prey, such as those in the Okavango delta - still grow big. Sadly, the fatal persecution of the California grizzly lowered the average size of lower 48 states US bears - some of those were 'legendary' as big sized beasts. The same goes for Siberian/Amur tigers, on averge the few still extant are smaller than the sizes they previously reached, right up to the last hundred years or so. Grizzly bears of the Sierra Nevada Mountains and those of the prairie were larger than those of the Rocky Mountains. Unfortunately, only a small portion of Rocky Mountain grizzlies survived the slaughter of predators which took place in the lower 48.
|
|
|
Post by brobear on Dec 27, 2018 15:08:17 GMT -5
www.prehistoric-wildlife.com/species/p/panthera-leo-atrox.html Panthera leo atrox/Panthera atrox (a.k.a. American lion, Naegele’s giant jaguar & American cave lion) Name: Panthera leo atrox Phonetic: Pan-fee-rah lee-oh a-troks. Named By: Joseph Liedy - 1853. Classification: Chordata, Mammalia, Carnivora, Felidae, Panthera. Species: Panthera leo atrox. Diet: Carnivore. Size: 1.2 meters high at the shoulder, up to 2.5 meters long. Known locations: North America, also known from places in South America. Time period: Late Ionian to Tarantian of the Pleistocene. Fossil representation: Hundreds of specimens, but often of fragmentary remains. Classification confusion Today the American lion is usually treated as a sub species of the African lion (Panthera leo) which is why it is more commonly credited as Panthera leo atrox. However there are a large number of researchers who consider the American lion to be different enough from the African lion to give it its own distinct species of Panthera atrox, which is actually the original classification. However this is just the tip of the iceberg when dealing with the classification of the American lion and it’s easy to become lost amongst the multitude of theories and arguments about its true position amongst other members of the Panthera which includes most modern day big cats. Early study of the American lion led to it being considered similar to a Jaguar (Panthera onca), and in the mid-1990s it was even considered to be a sub species of tiger (Panthera tigris) based upon similarities to the skull form. The American lion has also been considered to not be a lion at all but a distinct big cat that did not survive into modern times. Most palaeontologists however do agree that the American lion is most closely related to the Eurasian cave lion (Panthera leo spelaea) which is itself is has also been treated as a distinct independent species as well as a sub species of the African lion. This has been confirmed by mitochondrial DNA analysis which shows that the American lion and Eurasian cave lion were almost identical, although the American does seem to have grown slightly larger. Current thinking is that Eurasian cave lions crossed over the Bering Strait into North America during the Ionian stage of the Pleistocene only to be cut off from the rest of the world by glacial activity. The resulting small population would have had a limited gene pool where new traits such as growing slightly larger would have been easier to establish, especially if the larger size was of a benefit in the new environment. Range and ecological role American lions seem to have been widespread across North America with remains known from Alberta in Canada, past the great lakes to the east coast, all the way back to the Pacific coast in California. American lions also crossed the Isthmus of Panama to colonise South America, thus taking part in the great American interchange that began during the Pliocene. This is where animals crossed the land bridge between north and South America to intermix with other animals that were previous isolated. The earlier spread of large North American predators are thought to have been responsible for displacing the phorusrhacid terror birds similar to Kelenken and Phorusrhacos from their positions as top predators from the South American landscape, as they seem to have already disappeared by the time that the American lion reached South America. African lions can run at high speed but they are not built for prolonged chases, and will often give up the chase if a prey animal quickly outpaces them. The American lion, although larger than the African still had proportionately short legs that would have enabled it to reach top speed fast, but would have limited its ability to keep pace with longer legged animals like horses which could use their wider striding distance to run even faster. This means that the only way the American lion could effectively hunt was to use ambush tactics to surprise its prey so that by the time the target realised the danger it was in, the lion was already making its strike. Like with most predators the American lion probably approached its intended victim from downwind which means the prevailing wind would blow the lions body scent away from the prey so that it did not know the lion was there. Lions like other cats typically squat down low and creep towards they prey while staying in long grasses that conceal the lion’s body, but still allow the lion to see the prey animal because it’s standing above the grass. Once the lion has gauged that it is close enough it will sprint the final distance leaping onto the back or flanks of the prey trying to knock or wrestle the prey so that it loses its footing and collapses to the floor. Here the lion’s retractable claws come into use to gain extra grip upon the prey. When not used for grappling with prey these claws retract back into the paw so that they are prevented from contacting the ground so that they stay sharp. Lions will typically use one of two methods to dispatch their prey. First is they may try to clamp their jaws around the throat of the prey and crush the windpipe so that the prey asphyxiates (becomes starved of oxygen which causes it to stop breathing, possibly also triggering cardiac arrest). The second is what is known as the ‘muzzle clamp’, and like the throat bite this prevents the prey from breathing that leads to asphyxiation, but here the lion closes is jaws around the tip of the snout of the animal. The latter method is often used on prey that manages to stay on its feet despite the lion’s strength. Pack or solitary hunter? Although African lions can be seen hunting in groups called ‘prides’ today, it is not certain if the American lion did so as well. In fact evidence from the Rancho La Brea tar pits in California, USA may suggest that the American lion was a solitary hunter. The tar pits at Rancho La Brea have yielded a wealth of different fossil remains with by far the most numerous being dire wolves and Smilodon (better known as the sabre-toothed cat) while other carnivores like Arctodus (short faced bear) and the American lion are in much smaller quantities by comparison. Dire wolves almost certainly hunted in packs like their surviving modern day counterparts the grey (Canis lupus), and Arctodus was almost certainly a solitary animal like other bears, both ideas supporting the abundance and lack of their associated remains. Smilodon also seems to have had a preference for large prey like bison which would have been easier to hunt in groups. Additionally a 2009 study of African predators (By C. Carbone, T. Maddox, P. J. Funston, M. G. L. Mills, G. F. Grether and B. Van Valkenburgh) played the sounds of animals in distress as if they were stuck in mud out to the surrounding landscape. The team found that while large animals that hunted in packs had the lowest populations in the ecosystem, they were the most likely to respond to the calls. Individual predators however tended to keep their distance, perhaps to stay out of the way of the larger predators that they knew were coming. Again this observational data corroborates the expanse of some predators at La Brea, while others are in very small numbers. While the above idea is plausible, there are a few ideas that counter the theory that American lions were solitary hunters. One is that American lions were not that common with competition from Smilodon among other predators reducing the number of American lions active in Pleistocene California. It may also be that the American lions in La Brea were individuals that had been kicked out of prides and were left with little choice but to try and scavenge the carcasses in the tar pits. Today, prides of African lions are ruled by a dominant male, but periodically this male will have to fight other roaming males that will challenge the male for control of the pride and right to mate with the females. It is also worth considering that American lions may have had different behaviour in approaching stuck animals at La Brea with perhaps one lion walking ahead of the others to test the ground. If the lion made it to the stuck animal and seemed to be okay the others would follow, but if the forward lion became stuck the others would stay back, their core survival instincts holding them back from placing themselves in danger. Although pure conjecture, this strategy is similar to how in the army one soldier walks point in front of the others as they are advancing. The point guard is usually the first to take enemy fire, but this often allows the main group to take cover and respond. One final note about the possibility of the American lion hunting in packs is actually associated with the Eurasian cave lion. In Europe cave art left behind by early people depicts the Eurasian cave lion as hunting in groups. With the American lion considered an off shoot of the Eurasian cave lion, it’s reasonable to infer a greater possibility of this lion hunting in prides.
|
|
|
Post by Lion genetics. on Jan 3, 2019 18:23:53 GMT -5
In a 2009 study 'P-leo Atrox body proprtions, size...' by Wheeler and Jefferson, the largest specimen examined was computed to weigh "457kg" when alive, that's a big lion.
Felids scale well, so from the tiny 2kg sand cat, right up to P-leo Atrox, they retain effective morphology function, even if wild cats nowadays top out at ~300kg, mainly due to prey availability constraints.
As brobear has noted, a similar situation appends to grizzly bears, where 'barren ground' bears cannot find enough food to grow/match size with historical California grizzlies, or the salmon-fed coastal brownies.
|
|
|
Post by brobear on Feb 18, 2019 4:46:35 GMT -5
www.felidaebigcats.info/onepager/en/ About the evolutionary history of felids. The ancestral lineage Panthera, which includes only two genera (Panthera and Neofelis), is the only line included within the subfamily Pantherinae. The other seven ancestral lineages belong to the subfamily Felinae. An alternative approach exists, which relies more on genetic affinities, placing all eight lineages in the Felinae subfamily.
|
|
|
Post by brobear on Feb 22, 2019 15:34:24 GMT -5
In Pleistocene N. America, I don't believe that Arctodus simus was ordinarily a big threat to the grizzly. The giant was a scavenger while the Ice-Age grizzly was an omnivore and predator. A bigger threat to the grizzly were the multitude of big cats, especially to a she-bear with cubs.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 26, 2019 23:41:56 GMT -5
Harington (1969) enumerated four humeral traits typical of the humerus of P. atrox: (1) general robustness comparable to Smilodon and Homotherium; (2) great anteroposterior expansion of the medial epicondyle; (3) sharp, posteriorly directed crest below the medial epicondyle when the specimen is viewed laterally; and the outward flair of the lateral condyloid crest, which is concave to straight in Smilodon. All these features are present in MLP 94-VIII-10-15, but are absent in Panthera onca. Additionally, as indicated above, the general shape of the distal trochlea, the form and size of the supracondyloid foramen, the ridge delimiting the lateral edge of the olecranon fossa, and the morphology of the lateral epicondylar crest in lateral view, are features that may prove useful to differentiate P. atrox from P. onca (Fig. 3). Chimento, Agnolin (2009) Studies of limb bone length ratios of P. leo have grouped it with other terrestrial felids living in open environments and using the pounce-pursuit hunting style (Harrington, 1969; Gonyea, 1976, 1978; Anyonge, 1996b; Harris and Steudel, 1997; Meachen-Samuels and Van Valkenburgh, 2009; Meloro et al., 2013). Harrington (1969) and Anyonge (1996b) have commented on the similarity of P. leo to the extinct P. atrox, based on limb proportions. Hartstone-Rose et al. (2012) showed the similarity of P. leo and P. atrox clavicles. However, Anyonge (1996b) noted that the cross-sectional geometric properties of the P. atrox limb bones approach those of Ursus arctos (brown bear). According to Kurten (1952), Scandinavian bears, in preparation for the killing bite, place one paw over the prey’s shoulder and one paw over the face. This bends the prey’s head, which exposes its arch of the throat and brings blood vessels in ventral neck upward (Wheeler, 2011). The similarity of P. atrox limb bones to U. arctos may indicate similar hunting behavior and increased need for musculo-skeletal strength in P. atrox. Carlon (2014) The Zx/Zycanine value of Panthera atrox (1.84; Fig. 5) is much higher than that of other large felids and similar to Neofelis nebulosa, indicating that dorsoventral stresses prevailed in the symphyseal region and that labiolingual and torsional stresses exerted by struggling prey were relatively lower. While it is generally agreed that the large body size of Panthera atrox allowed it to tackle very large herbivores, such as bison, horses, ground sloths, camels, and proboscideans (e.g. Kurt´en & Anderson, 1980; Harris, 1992; Anyonge, 1993), it seems paradoxical for this Pleistocene predator to have experienced lower torsional stresses than by extant lions that hunt smaller prey (Schaller, 1972). Although extant felids use their forelimbs and claws to restrain prey (Gonyea&Ashworth, 1975), their jaws must still be able to remain locked on the neck or muzzle of prey and withstand the unpredictable stresses induced as prey struggle to escape. If Panthera atrox were a predator of large herbivores, one would expect it to have Zx/Zycanine values similar to, or even lower than, those of extant lions. Claw and tooth marks left on a Pleistocene steppe bison mummy (Bison priscus; M. L. Guthrie, 1988; R. D. Guthrie, 1990) suggest that Panthera atrox adopted killing techniques similar to those used by modern lions. 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. Furthermore, because the Zx/Zycanine values of Panthera atrox are so high, it is possible that cooperative hunting may have been common practice in that species, where one or a few individuals would have restrained a large herbivore while another delivered the canine killing bite. Indeed, the high degree of cephalization observed in Panthera atrox (Kurt´en & Anderson, 1980), the claw and tooth marks left on a bison mummy, and native American cave paintings (M. L. Guthrie, 1988; R. D. Guthrie, 1990) suggest that the extinct lion may have hunted in small groups of two or three individuals, rather than in a pride. This possibility is further supported by the size distribution of Panthera atrox individuals in the Rancho La Brea deposits, which indicates that the extinct lion did not form prides as modern lions do but may have hunted in pairs or alone (Jefferson, 1992). Therrien (2009) Credited to Ursus21/Gaurus from Carnivora: carnivora.net/showthread.php?tid=3906If you read the sentences highlighted in red, the p. atrox@american lion has stronger limbs than an african lion being closer to those of a brown bear meaning bears have more powerful foreams than cats.
|
|
|
Post by King Kodiak on Mar 29, 2019 6:19:43 GMT -5
Nice find there Bjorn. American lion had stronger limbs than modern lions ok. So you can just imagine, the Pleistocene grizzly would have wrecked the American lion 1 vs 1, this means that a brown bear would wreck a lion much more so in modern times.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Apr 27, 2019 8:44:49 GMT -5
Nice find there Bjorn. American lion had stronger limbs than modern lions ok. So you can just imagine, the Pleistocene grizzly would have wrecked the American lion 1 vs 1, this means that a brown bear would wreck a lion much more so in modern times. Completely agree with you. Even a polar bear could beat an american lion, smilodon, cave lion, any any tiger or lion one on one. The Pleistocene grizzly is stronger than a polar bear pound to pound.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on May 24, 2019 4:22:12 GMT -5
In Pleistocene N. America, I don't believe that Arctodus simus was ordinarily a big threat to the grizzly. The giant was a scavenger while the Ice-Age grizzly was an omnivore and predator. A bigger threat to the grizzly were the multitude of big cats, especially to a she-bear with cubs. Agree with you on that. Grizzly bears which are unable to climb unlike black bears prefer do use aggression rather than flight. Living among a multitude of predators explains the aggression of a mother grizzly: willing to fight to her death to defend her cubs. I wonder how socialble extinct cats are. It seems that cave lions are not as socialble as African or Barbary lions.
|
|
|
Post by brobear on Oct 26, 2019 4:42:14 GMT -5
I firmly believe that the Pleistocene grizzly was killed more often by large Pleistocene cats than by Arctodus simus. A grizzly could easily avoid the ponderous giant bear. And the giant was not a hunter. But juvenile bears were very likely hunted by the big cats just as they are in Russia today. Even adult grizzly she-bears were likely preyed upon occasionally. Would a lone Smilodon, Homotherium, or Atrox ambush a mature male grizzly? A tiger will not choose a male grizzly as potential prey. The saber-toothed cat and the scimitar cat were both about the same size as a modern lion or tiger ( although perhaps heavier ). The atrox was larger, though still ( perhaps ) outweighed by a typical male grizzly. The Pleistocene grizzly is believed to have weighed on average from 500 to 700 pounds. I believe that as with lions, a group of big cats will not attack anything that a lone cat would fear to attack. Someone has to go first. For a mature male grizzly to be ambushed in Pleistocene N. America, Europe, or Asia would have likely been a rare incident.... imo.
|
|
smedz
Ursus abstrusus
Recent Graduate
Posts: 410
|
Post by smedz on Dec 22, 2019 19:30:46 GMT -5
The Great Cats of The Woods
Big Cats have always captured our imaginations, and have also stroke fear into the hearts of those who lived with them. With living cats, the lion and tiger capture most of the imagination. When it comes to extinct felines, no cat captures our imaginations more than Smilodon. Or to be more specific, Smilodon fatalis. But he was not alone, as he coexisted with another cat that would have rivaled him in size and power, Panthera atrox, or the "American Lion". Both coexisted with each other for millions of years, and it's pretty rare to find two massive cats living in the same ecosystem. The theory in the past was that Smilodon, P.atrox, and the Dire Wolf coexisted on the plains, all competing for the same prey such as horses, camels, and bison. However, a new scientific study has debunked this theory. Past studies on these animals diets were done with isotopic analysis of the bone collagen. This new study on the other hand involved isotopic analysis of the teeth enamel because it is now known that tooth enamel is more reliable than bone collagen because it is isn't as prone to being messed with in the fossilization process. With this, the experts found that Smildon and P.atrox were more forest dwellers and hunted animals like deer and tapirs while dire wolves were hunting on the plains for horses and bison. But how did these two massive cats coexist with each other for so long? Well, lets look at the situation shall we?
In an ecosystem, there is what's called the Competitive Exclusion principle which says that no two species can have the exact same niche in the exact same place at the exact same time. But if enough resources exist in an ecosystem, a niche can be somewhat shared. But a question that must be answered is were these cats social or solitary? Smilodon Regarding to whether this animal was social or solitary has been the subject of debate over the years. In recent years however, it appears experts have begun abandoning the idea of Smilodon being a solitary animal. One big piece of evidence of the cats being social is the high number of healed injuries on the bones that have healed. These injuries included crippled pelvises, dislocated elbows, broken legs and other injuries that would have prevented these animals from hunting. Despite this, the animals lived long enough for the bones to heal. On the other hand, some argued against the sociality of Smildon. One argument was that Golden Eagles which are solitary are also a very common find at Rancho La Brea, so just because a species is a common find does not mean that species was social. But just because one species isn't social does not mean another common species wasn't social. Another argument was that the small brain of Smildon was not consistent of a social life. However, research has found that tigers, relative to body size, have a larger brain than lions! Now this does not mean tigers are smarter by any means, but what it does mean is that there is no correlation between brain size and social life in cats relative to body size. The final argument was that cats used metabolic reserves to heal quickly without eating and can survive with access to water. Now, analysis of the wear patterns of the teeth of healthy Smilodon and injured Smilodon showed that healthy cats munched on flesh and bone while injured cats ate the softer parts of a carcass. Meaning that the injured cats were eating after all. So it's very safe to say that Smildon fatalis were social animals. How big the packs were is anyone's guess. But there is one thing that's a bit off. The habitat. In open plains and grasslands, there are many advantages for big cats at least the size of lions to live in groups. But Smilodon fatalis was a forest cat, so why would it need to be social? The answer may have been because of cubs. Smilodon cubs could take up to 22 months to get most of their adult teeth, and the massive canines would take up to 3 years or more to get to their full size. Not only that, but it may have taken Smilodon cubs longer to learn how to safely hunt bug prey without breaking their canines. Living in groups would have allowed for cubs to develop more slowly because of the bigger safety net, and with a number of threats around, that would have comes in handy. In other words, Smilodon fatalis may have lived in groups just to protect their cubs. Panthera atrox I no longer believe Panthera atrox to have been a social animal. But I'm going to explain why. American Lions aren't nearly as frequent at the tar pits as Smilodon and Dire Wolves. P.atrox occurrency at La Brea is 2.6% while Smilodon occurrency is 33.3% and dire wolf occurrency is 51.2%. Likely meaning that P.atrox wasn't as social because social carnivores were more likely to react to distress calls because they had the better backup. But P.atrox being solitary would have known the tar pits were a good place to encounter the groups of Smilodon and so they normally stayed away. On the other hand, coyotes and Gray Wolves aren't common at Rancho La Brea and they're social, but you also have to remember that they coexisted with Dire Wolves on the plains and dire wolves were bigger and more powerful than both of the smaller canids and most certainly would have killed them when given the chance. So avoiding the tar pits meant avoiding the larger canid. Then there's the habitat of the American Lion, which was forest. In forested environments, big cats have no need to be living in groups as they can easily hide their kills from scavengers and cover for hunting isn't an issue. But what about protecting cubs? You might be thinking "But didn't you just say Smilodon probably lived in groups to protect their cubs?" Yes, but Smildon cubs probably took longer to develop and being in a group would have allowed that. Pantherine cats on the other hand don't have this problem. But for a modern day example, think of the Amur Tiger. Here is a list of animals in the Russian Far East that would be more than happy to kill tiger cubs. 1. Other tigers 2. Brown Bears 3. Asiatic Black Bears 4. Wolves 5. Amur Leopards 6. Eurasian Lynx 7. Dholes (Historically) These tigers live with many tiger cub killers, and they do not live in groups and they are forest cats. Therefore, and this is my strict opinion, it is more than likely that Panthera atrox was a solitary animal, probably with a social structure like a tiger with one male controlling a big territory that overlapped with those of several females. The Relationship As with all wild cats, these two would not have liked each other. With Smilodon being the social cat and Panthera atrox being the solitary cat, the pantherine would have avoided areas where the sabertooth hunted for fear of encountering a pack. But there may have been times when a P. atrox could have caught a lone sabertooth off guard from ambush, but in general, Smildon would have been the dominant cat. www.sciencenews.org/article/saber-toothed-cats-smilodon journals.plos.org/plosone/article?id=10.1371/journal.pone.0052453 www.sciencedaily.com/releases/2009/09/090911145030.htm www.smithsonianmag.com/smart-news/fossils-reveal-why-coyotes-outlived-saber-toothed-cats-180972826/ www.ncbi.nlm.nih.gov/pubmed/12697957
|
|
|
Post by King Kodiak on Jan 2, 2020 18:21:04 GMT -5
AMERICAN LION (PANTHERA ATROX)
|
|
|
Post by OldGreenGrolar on Jan 3, 2020 5:51:23 GMT -5
Looks like exceptionally big American lions might be able to surpass 500 kgs as they have heavier bones than extant tigers and lions. Yet both the brown bear and polar bear would still be stronger than the American lions and better grapplers as well.
|
|
|
Post by brobear on Jan 3, 2020 9:23:49 GMT -5
From GrizzlyClaws ( a very impressive poster ): Bears are resilient animals as it can rely on many sources of food. Eating plants when there was not enough meat, meanwhile to steal the carcass from your opponent to acquire more protein. The SF bear was probably too big to be messed with, but not the much smaller American lion. As the Pleistocene grizzly might be 50% heavier than an adult male American lion, and I do believe that the success rates for the Pleistocene grizzlies to steal the carcass from those lone American lions might be quite high. I agree; a grizzly can and will displace any species of big cat from a carcass unless the cat has the advantage of numbers.
|
|
|
Post by King Kodiak on Jan 3, 2020 15:40:39 GMT -5
|
|
|
Post by brobear on Jan 3, 2020 15:49:15 GMT -5
Panthera atrox had the strongest jaws and the biggest brain of any known big cat ever. There were fewer atrox and bears caught in the La Brea Tar Pits than other big cats or even wolves. It is my opinion that this is partly due to the fact that the atrox and various bear species had enough intelligence to perceive the danger and to reject the strong temptation of easy-to-reach meat.
|
|
|
Post by brobear on Feb 14, 2020 5:14:47 GMT -5
Smilodon fatalis and Panthera leo atrox. This is why I consider the atrox as a greater adversary for the grizzly than the saber-toothed cat. Smilodon had the longer canines but atrox had the strongest jaws. Smilodon was more muscular, but atrox was bigger and smarter.
|
|
|
Post by brobear on Feb 25, 2020 5:58:31 GMT -5
ME: I agree and, in fact, I believe that the big Pleistocene cats were a greater threat to the grizzlies than the short-faced bears. A grizzly could more easily avoid the giant bears, but the big cats were hunters. The life of a grizzly she-bear had to have been horrific. Even a big boar grizzly had to be on constant alert. Spelea: The Grizzly's life would have been hard, no doubt about it. But they are very smart animals, they could avoid direct confrontations with arctodus , and let us not forget they hibernated during the winter and thus if the American lions, the Arctodus and the dire wolves were tired at the end of the winter, the grizzly reappeared at spring in front of weakened competitors.
And yes, as you say, I believe the big cats (especially American Lions living in prides and being social hunters) were its most direct threat.
May be yes too, the dires wolves if they hunted in very large prides (for exemple more than 50 members, after all it would have been possible before the men intervened) could also play an important role.
|
|
|
Post by brobear on Apr 22, 2020 4:17:27 GMT -5
www.wired.com/2011/10/american-lion-or-giant-jaguar-in-search-of-panthera-atrox/ American Lion, or Giant Jaguar? - In Search of Panthera atrox The Page Museum at the La Brea Tar Pits is a wonderful place. I don’t mean wonderful in the overused, everyday sense of “That pizza was wonderful”, or “If you could hand in your TPS report before you leave the office, that would be wonderful.” I mean that the museum is literally a place that fills my fossil-loving heart with wonder. Even though I had seen photos of the exhibit before, I was still stunned by the glass case containing the dark brown skulls of over 350 dire wolves, and I was delighted to get a brief tour of the fossil-filled boxes that are currently being excavated behind the building. But there was one thing that hooked into my brain and wouldn’t let go during my visit to the Page. Among the museum’s exhibits were composite skeletons of some of the charismatic Pleistocene mammals which perished in the asphalt seep that now sits in the middle of Los Angeles. All the classic characters were represented – the Shasta ground sloth, Bison antiquus, the deep-snouted bear, the sabercat Smilodon, the Columbian mammoth, and others. I had read about these animals before and seen other skeletons of their kind elsewhere, but the label on one of them puzzled me. For as long as I could remember, the big cat Panthera atrox was commonly known as the “American lion” – a now-eliminated branch of the famous cats which long-ago reached North America. The plaque in front of the formidable pantherine’s skeleton called it something else – Naegele’s giant jaguar. Since when had America’s own lion been transformed into a burly jaguar? A pair of publications I picked up from the museum’s gift shop further catalyzed my confusion. In a revised, 2001 edition of paleontologist Chester Stock’s monograph *Rancho La Brea: A Record of Pleistocene Life in California *the fossil cat was cast as “lion-like”, though the brief passage also mentioned that Panthera atrox “has also been called a gigantic jaguar.” Not much help. The glossier, popular-audience pamphlet *Rancho La Brea: Death Trap and Treasure Trove *didn’t resolve the issue, either. A summary contributed by George T. Jefferson simultaneously identified the cat as both Naegele’s giant jaguar and a subspecies of lion (Panthera leo atrox). While treated and illustrated as a lion, Jefferson repeatedly called the animal a giant jaguar. Clearly, I had to dig deeper. Paleontologists have been kicking around different ideas about the identity of Panthera atrox since the mid-19th century. On the basis of a partial lower jaw containing three molars and a broken canine, the Philadelphia polymath and naturalist Joseph Leidy called the fossil cat “Felis” atrox. He described the cat as “a species which much surpassed in size the recent Tiger and Lion, or the extinct Felis spelaea [“steppe lion”] of Europe.” The specific traits of the jaw resembled their counterparts in all three big cats – living and extinct – but Leidy ultimately categorized the felid as “an extinct species of American lion.” Not everyone was agreed that Leidy’s cat – what we now call Panthera atrox – was really a lion. During the first half of the 20th century, especially, experts on fossil mammals such as the French paleontologist Marcellin Boule and his German colleague Max Hilzheimer noted that Panthera atrox appeared to exhibit a mosaic of features shared with both lions and tigers. This uncertainty was echoed by studies of some of the early fossils excavated from the La Brea asphalt seeps and described by paleontologists John Merriam and Chester Stock. In their major 1932 monograph on Panthera atrox, the two concluded that the skull of the fossil cat most closely resembled that of the jaguar, Panthera onca, a few specimens of which have also been found in the same deposits. The eminent American paleontologist George Gaylord Simpson agreed with the determination of Merriam and Stock in his own 1941 review of the Pleistocene’s large fossil felids, and he bemoaned the fact that Panthera atrox had become popularly known as the “American lion.” The cat was no lion, Simpson argued, just as saber-toothed cats were not truly tigers. Continued use of the outdated terminology would only further mislead an American public that had a hard enough time understanding family relationships among fossils as it was.
|
|
|
Post by brobear on Apr 22, 2020 4:19:33 GMT -5
Continued: Of course, the interpretations of Boule, Hilzheimer, Merriam, Stock, and Simpson were not universally accepted, either. If anything, the image of Panthera atrox as a North American lion held out against the jaguar interpretation. The cat, as I first encountered it, was a huge lion which hunted alone or in pairs in the open landscapes of the Pleistocene west. Most museums I have visited with Panthera atrox mounts have followed this trend. But, in my search for more information, I found at that a more jaguar-like version of the cat was again proposed just two years ago by paleontologists John M. Harris - curator of the Page Museum - and Per Christiansen. Christiansen and Harris focused on the cranium and jaws of Panthera atrox. More than any other part of the skeleton, the head of the cat has most often cited as evidence that Panthera atrox shared more in common with jaguars than lions or other big cats. In order to detect the affinities of the fossil cat, Christiansen and Harris compared a series of measurements from a sample of well-preserved Panthera atrox specimens from the La Brea deposits to the same measurements made from the skulls of tigers, lions, and jaguars kept at other museums. The sample, as Harris recounted in response to an email I sent about the study, included "78 tiger skulls, 176 lion skulls and 57 jaguar skulls, [and] the 14 P. atrox skulls from Rancho La Brea." As many paleontologists had determined before, the skulls of Panthera atrox exhibited a mosaic of features which did not entirely match any of the living species. Whereas the crania of the fossil cats were more lion-like than anything else, some aspects of their lower jaws appeared to be more tiger- or jaguar-like. When I asked Harris about which features particularly placed Panthera atrox closer to jaguars than to lions, he cited the “mandibular ramus, mandibular symphysis, fronto-maxillary suture, and shape of nasal opening.” The last of these features is self-explanatory, but, for those who have not taken osteology in a while, the other three are the large flange of the lower jaw which connects to the cranium, the fused portion of the lower jaws which meet at the midline, and a suture in the skull along the frontal and upper-jaw (maxillary) bones. The Panthera atrox skulls, Harris said, “were closer to lions or tigers in some other features but multivariate and other statistical analysis suggested that P. atrox did not group with lions and was closest to jaguars.” Curiously, though, in the paper Christiansen and Harris pointed out that the crania of Panthera atrox most closely resembled those of lions and deviated most from the crania of jaguars. As they wrote in the paper, "Panthera atrox differs from the lion, jaguar, and tiger in many osteometric skull variables, most often from the jaguar (21) and least often from the lion (16)." Even in regard to the fossil cat’s lower jaw, the range of variation among the lions and other extant cats in the study resulted in some of the comparisons being murky. Panthera atrox was not precisely like a modern day lion, but, from what I could see, the data gave no clear sign that the cat could be accurately called a “giant jaguar”, either. Nevertheless, Christiansen and Harris cited their results as support for the idea that Panthera atrox occupied an intermediate place between a subgroup of lions/leopards on the one hand and tigers/jaguars on the other. Rather than being “a kind of giant, North American lion,” the researchers hypothesized, the anatomy and reconstructed ecology of the animal hinted that Panthera atrox “appears to have been close to a type of giant jaguar” which eschewed the forest for more open hunting grounds. I asked Harris, in his estimation, what the cat would have looked like when alive. He replied: *P. atrox *is appreciably larger than both jaguars and lions. It had proportionately longer legs than those of jaguars, which may have been an adaptation for running in more open habitat. If so, this might explain why jaguars and giant jaguars are seldom found at the same locality. They both occur at La Brea, where we have over 80 individuals of P. atrox but only one or two of P. onca. What the pelage of P. atrox looked like is open to conjecture. If, indeed, it was a more open habitat form it may have had an unspotted or only faintly spotted coat.
|
|