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The “American Lion” is not a lion

By Hans-Dieter Sues

Among the great mammalian predators from the Pleistocene Epoch (1.8 million to 10,000 years ago) of North America, an enormous cat stands out. Only the giant bear Arctodus simus (discussed in a previous blog) exceeded it in size. No, I am not talking about the famous saber-toothed cat, Smilodon fatalis.

Renowned American naturalist Joseph Leidy first described a large extinct cat (which he named Felis atrox, “cruel cat”) in 1853 based on an incomplete lower jaw with teeth from Mississippi. Since then, bones of this predator have been recovered from Pleistocene deposits across the United States and in Canada.

The best fossils of what now is known as Panthera atrox have been found in the La Brea “tar pits,” which today are located in the Miracle Mile district of Los Angeles.

At La Brea, crude oil has slowly been seeping to the surface through deep fissures in the ground for the last 40,000 years or so. The light fraction of this oil evaporates, leaving deposits of thick, sticky asphalt (usually incorrectly referred to as “tar”). Water often collected on and covered the asphalt, luring thirsty animals to their doom. Over countless millennia, many animals and plants have been preserved in these deposits.

Many of the species found as fossils at La Brea still live in the Los Angeles region. However, the big mammals–including saber-toothed cat, dire wolf, mammoths, mastodon, ground sloths, long-horned bison, and camels–vanished about 11,000 years ago.

Some 90 percent of the large mammal fossils collected from La Brea belong to carnivores. Most of the bird remains also belong to forms that are predators and (or) scavengers –eagles, an extinct group of enormous birds known as teratorns, vultures, and condors. Presumably the plight of mired animals attracted predators, which then joined their intended quarry in the deadly embrace of the asphalt. In addition, some carnivores may have inadvertently become trapped while pursuing their prey across the sticky ground.

The relationships of Panthera atrox, often called the American lion, to other big cats have long been contentious.

John C. Merriam, a renowned paleontologist from the University of California at Berkeley, and his students first started scientific investigation of the La Brea fossils in 1901. In 1932, together with his former student, Chester Stock, Merriam published a classic monograph on the extinct cats, including Panthera atrox, from La Brea.

The two researchers noted many similarities between Panthera atrox and present-day lions and tigers (Panthera tigris). However, they concluded that overall the skull of the extinct cat was most like that of the jaguar (Panthera onca). Some later authors accepted this view, but other experts considered Panthera atrox most closely related to the African lion (Panthera leo) and its extinct Eurasian relative, the cave lion (Panthera spelaea). A few paleontologists even went so far as to assign the extinct American cat to Panthera leo rather than to a separate species.

A new study by the Danish zoologist Per Christiansen and the American paleontologist John Harris has recently clarified the relationships of Panthera atrox to other big cats (Pantherinae). The two researchers employed a variety of methods for statistical and shape analysis to compare large samples of skulls of present-day and extinct pantherine cats.

Panthera-atrox-skull-illustration.jpg

Side view of a complete skull of Panthera atrox from La Brea, now housed in the collections of the University of California Museum of Paleontology. The length of this skull (measured from the tip of the snout to the back of the base of the skull) is 40.6 cm (16 in.). The illustration was scanned and digitally modified from the classic monograph by Merriam and Stock (1932) on the extinct cats of La Brea and represents a fine example of traditional scientific illustration.

Source: The Carnegie Institution of Washington.

Their analyses confirmed that the skull of Panthera atrox shares similarities with those of lions but also revealed many differences. The lower jaw of the extinct cat was more similar to those of the jaguar and tiger but also had features not found in any of the present-day big cats.

In a comprehensive analysis of 23 skull dimensions, Panthera atrox emerged as quite distinct from lion, tiger, and jaguar. A separate study of the evolutionary history of pantherine cats by Christiansen placed the “American lion” closest to the jaguar (Panthera onca).

The work by Christiansen and Harris makes a compelling case that Panthera atrox was, in fact, a kind of giant jaguar rather than a lion. There exists no evidence now that true lions ever immigrated to the Americas.

Panthera atrox was one of the largest true cats of all time, reaching an estimated weight of at least 351 kg (772 pounds). It apparently lived in open habitats and presumably could tackle even prey as large as a bison. Although present-day jaguars prefer forest settings the largest individuals are usually found in less forested habitats.

Writing this blog I am inspired by the cats sharing their lives with my family and me. They are beautiful (if much less menacing) examples of one of the most successful groups of predators in the history of mammals.

Hans-Dieter-Sues.jpgHans-Dieter (Hans) Sues is a vertebrate paleontologist based at the National Museum of Natural History in Washington, D.C. He is interested in the evolutionary history and paleobiology of vertebrates, especially dinosaurs and their relatives, and the history of ecosystems through time.

A former member of the National Geographic Committee for Research and Exploration, Hans has traveled widely in his quest for fossils and loves to share his passion for ancient life through lectures, writings, and blogging.

Blog entries by Hans-Dieter Sues >>

Comments

  1. samantha cottom
    illinois
    October 20, 2013, 5:35 pm

    is this true if not I love am at Trico Elemantry SCHOOL

  2. @raptorshuffle
    papua
    March 24, 2012, 7:08 am

    ligerjag (lion tiger jaguar)

  3. Wade Rose
    Virginia
    January 18, 2012, 10:08 am

    We have genetic evidence that P. atrox is infact the same species as P. Spelaea and P. vershchagini. This pretty much blows a big hole in this article and determining species by analysis of slight skull or size differences in the animal. From my recollection the ability to breed is the primary and defining characteristic of a breed. Well I’m about a foot taller and 200lbs heavier than my Japanese in-laws.

  4. Lucian
    July 1, 2011, 12:38 pm

    I agree with emaniac69. A single test based solely on skull appearance is bound to fail. That’s like saying a bulldog is a whole different species than a German sheperd, because their skulls are very different. Anatomy differentiation is also closely related to habitat and thus prey. Modern day lions hunt mostly animls in the 300 kgs size. When it comes to taking down larger animals like buffaloes, they work in numbers. The American lion was hunting much larger prey and was highly probable that it did it alone or in pairs, rather than very large prides. Therefore, it needed a new anatomy aquired through thousands of years of evolution. Also, the statement that no cave lions were found in the North American continent is nonsense. The East Siberian or Beringian cave lion was found not only in Russia, but also in Alaska and near the Yukon river of Canada, territories which are very much in North America. It is a clear evidence that Eurasian cave lions did migrate in North America.

  5. Abanoub B. Marcus
    Omaha, Nebraska.
    June 22, 2011, 12:45 am

    Hello! Do you know what MY two cents are? Well, here they are, Folks! You see, I believe that the American Lion was neither a lion, nor a jaguar, nor a tiger, nor a leopard. Instead, I rather believe that it was something very different, entirely! You see, according to that new study, Panthera gombagouesnsis (or however it’s spelt!), also known as the European Jaguar, migrated over the Bering land bridge, into the Americas. Then, it branched off into two sister taxa: The jaguar (Panthera onca), and the American “Lion” (Panthera atrox). However, that certainly DOES NOT mean that it was a Jaguar; instead, it means that it was simply a very close relative, of the Jaguar. And, also, do you know what is the closest living relative of the Jaguar, among the four extant Panthera species? Why, the African Lion! And, so, in my opinion, the rate of speciation went like this: African Lion begat European Jaguar, European Jaguar begat American “Lion”, and American “Lion” begat Jaguar. And, so, in my opinion, it was neither a lion, nor a jaguar, but, instead, rather, a completely different species, of large cats, entirely. However, in my opinion, it presumably constitutes the “Missing Link”, between the modern-day Lion, and the modern-day Jaguar.

    Now, as for its appearance, I think it looked very similar to this picture, right here:

    http://www.carnivoraforum.com/index.cgi?board=dinosaur&action=display&thread=4667

    In that picture, at the top of the page of that link, it shows it having faint, tiger-like stripes.

    So, what do you think about my hypotheses? Thanks! XD! :) !

  6. RichW9090
    May 19, 2010, 5:34 pm

    All that was found at Natchez was the type specimen, a partial lower jaw. Incidentally, anyone who has visited the Academy of Natural Sciences in Philadelphia has seen a bronze sculpture of this fossil – it is the jaw which the huge statue of Joseph Leidy is holding in its hand outside the front entrance.
    Very complete remains of the animal, including entire skulls and all the postcranial elements of multiple individuals were found at Rancho La Brea.
    I suspect you are trying to use the old argument against “Lucy” that part of her was found at a different location and stratigraphic level, to impugn the validity of P. atrox. Whether it is a lion or a jaguar, it is a valid species of large cat, known from many specimens from many localities in North and Central America.

  7. Uncle_Meat
    May 14, 2010, 6:11 pm

    “…an incomplete lower jaw with teeth from Mississippi.”
    And where did the rest of him come from? Rhode Island? New Jersey? :)

  8. emaniac69
    May 14, 2010, 12:42 am

    I just wanted to throw my two cents in, making sure that before I do I make it clear that I am studying psychology and not paleontology…
    Although I do not take a particular stance about the correct taxonomic categorization of P. Atrox, I do want to question the validity of this conclusion based solely on a morphological study. It is possible that this cat is not a lion at all but a jaguar, but based on the way that this was concluded the interpretation is still open to question. Even though the skull shows characters of lions, tigers and jaguars, a fact that Christiansen and Harris brought to refute the the overall proportion of the skeleton when considered as a whole is more similar to lions than the other two. In addition, it is difficult to assume that P. Atrox is directly related to jaguars without also providing genetic data supporting the conclusion. Although Christiansen and Harris may be correct, they have provided only one line of evidence; I am not sure that they have made a “compelling case” for anything. The only thing they have provided is a new hypothesis.
    I just wanted to point out that scientists have gotten in trouble in the past for relying solely on one source of data to base their conclusions. Just because people from Asian, African, and European descent have distinctive characteristics of the skull does not necessarily mean that they are separate species. Genetic evidence proves that even though peoples from different parts of the world have different physical characteristics, our DNA is nearly 100% identical.
    In other words, Christiansen and Harris need more data. Specifically, genetic data.