# Antartican organisms (extinct) **URL:** \ **Category:** Factual Questions\ **Created:** [June 19, 2012, 10:17pm UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686 "2012-06-19T22:17:38Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 19, 2012, 10:17pm UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/1 "2012-06-19T22:17:38Z")
Antartica was part of the Southern landmass, Gondwana, which also contained present-day India, Africa, South america, Australia and New Zealand. It was located in the tropics and gradually shifted southwards, until it reached its current position. So the question is, what was the life like in Antactica? I know only two terresrial plant species survived to the present-day, which are Antarctic hair grass and Antarctic pearlwort. But before it reached its current position it’s obvious the life was much more abundant. The biggest problem I think, is the fossils are now buried under tens of meters of ice blanket, so compared with other continents we know a lot less. But anyway, tell me what you know about the Antartica life (land plant and animals) AFTER the extinction of dinosaurs, and BEFORE it reached its present southpole location. Thanks. ---
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [June 20, 2012, 12:43am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/2 "2012-06-20T00:43:28Z")
tens of metres – meh. The ice blanket is up to 3km thick. And there’s your problem if you are putting together your ideas based on fossil evidence. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [June 20, 2012, 12:59am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/3 "2012-06-20T00:59:59Z")
Two percent of Atartica is ice free, mostly in the dry valleys and the fossil record has been extensively studied. There was lush tropical forests in Antartica even when it was very close to its present position, during a period of elevated co2 levels. > **[Secrets of Antarctica's fossilised forests](https://www.bbc.co.uk/news/science-environment-12378934)** > > Towering forests grew at the South Pole during the age of the dinosaurs. Now scientists ponder whether the past could be the key to the future. ---
**Author:** ![j\_sum1](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@j\_sum1](https://boards.straightdope.com/u/j_sum1)\ **Post date:** [June 20, 2012, 5:28am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/4 "2012-06-20T05:28:19Z")
2% isolated to a few specific areas isn’t much of a sample space. Not saying it is worthless, but there is a whole lot that is unknown. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [June 20, 2012, 5:53am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/5 "2012-06-20T05:53:27Z")
> [@j\_sum1](#): > > 2% isolated to a few specific areas isn’t much of a sample space. > Not saying it is worthless, but there is a whole lot that is unknown. There’s ice free areas on the Antartica peninsula and bare rock exposed on many mountains in Antartica as well as in the dry valleys. Some more finds listed here: > **[National Geographic](https://www.nationalgeographic.com/)** > > Explore National Geographic. A world leader in geography, cartography and exploration. Sure if the whole continent was exposed you’d find a lot more but considering it was joined to Australia not that long ago, we have a pretty good idea that before that the the flora and fauna was very similar to Australias fossil record. ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 20, 2012, 7:54am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/6 "2012-06-20T07:54:10Z")
> [@coremelt](#): > > There’s ice free areas on the Antartica peninsula and bare rock exposed on many mountains in Antartica as well as in the dry valleys. Some more finds listed here: > [National Geographic | National Geographic](http://news.nationalgeographic.com/news/2004/03/0309_040309_polardinos.html) > > Sure if the whole continent was exposed you’d find a lot more but considering it was joined to Australia not that long ago, we have a pretty good idea that before that the the flora and fauna was very similar to Australias fossil record. Are you saying that the land mammals in Antarctica were all marsupials? How diverse were they? Any fossils? ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 20, 2012, 8:39am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/7 "2012-06-20T08:39:24Z")
> [@coremelt](#): > > Sure if the whole continent was exposed you’d find a lot more but considering it was joined to Australia not that long ago, we have a pretty good idea that before that the the flora and fauna was very similar to Australias fossil record. Antarctica split from Australia well before it split from South America, which is why the Eocene fossil record of Antarctica is highly similar to that of South America, and utterly unlike that of Australia. That’s also why marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica. > [@griffon502](#): > > Are you saying that the land mammals in Antarctica were all marsupials? How diverse were they? Any fossils? They weren’t all marsupials by any stretch. There were several different groups of marsupials, including opossums and the ancestors of Australia’s marsupials. But there were also relatives of the armadillos and a several of the more bizarre South American hoofed animals as well. Basically Antarctica seems to have had the same mammal suite as South America, though a little less diverse in species terms because it was so damn cold. ---
**Author:** ![Kamrusepas](https://avatars.discourse-cdn.com/v4/letter/k/8c91f0/32.png) [@Kamrusepas](https://boards.straightdope.com/u/Kamrusepas)\ **Post date:** [June 20, 2012, 8:01pm UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/8 "2012-06-20T20:01:30Z")
Looks like I’ll have to be the first to say the obvious: Great Old Ones. [URL=“[Cthulhu Mythos deities - Wikipedia](http://en.wikipedia.org/wiki/Great_Old_Ones)”] ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 20, 2012, 10:13pm UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/9 "2012-06-20T22:13:49Z")
> [@Blake](#): > > Antarctica split from Australia well before it split from South America, which is why the Eocene fossil record of Antarctica is highly similar to that of South America, and utterly unlike that of Australia. That’s also why marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica. > > They weren’t all marsupials by any stretch. There were several different groups of marsupials, including opossums and the ancestors of Australia’s marsupials. But there were also relatives of the armadillos and a several of the more bizarre South American hoofed animals as well. > > Basically Antarctica seems to have had the same mammal suite as South America, though a little less diverse in species terms because it was so damn cold. Shame that the placentals never made it to Australia before the human influence except some bats. Just a single semi-domesticted dog (dingo) caused mass extinction of marsupials, and made the Tasmanian tigers extinct on mainland, that’s just an example on how inefficient the marsupials are when it comes to best-utilize the available resources. Marsupials simply are not competitive compared to placentals. One example is how they utterly failed to effectively colonize the mountain ranges in Australia, while in other parts of the world where the condition on the mountain terrain is much harsher, the placentals still thrive (e.g. goat-antelope species, camellids, hyrax species, marmot species, carnivores such as puma and snow leopard). From what you said though, it appears that the Southern Ungulates, are even less competitive, because they can’t even compete against the marsupials in Australia and became extinct there. No wonder they got wiped out so quickly when the true ungulates from North America arrived with the land bridge. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 21, 2012, 12:02am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/10 "2012-06-21T00:02:25Z")
> [@griffon502](#): > > Shame that the placentals never made it to Australia before the human influence except some bats. 1. Placentals arrived in Australia around 10 million years \*before \*the marsupials. They just didn’t arrive from South America. They were never common and they later became extinct. 2. Before humans arrived Australia had equal numbers of of placental mammals andd marsupials, just as it does today. Far from “some bats” Australia had huge numbers of species of bats and rodents. > [@](#): > > Just a single semi-domesticted dog (dingo) caused mass extinction of marsupials, and made the Tasmanian tigers extinct on mainland… No, it didn’t. Not only not a mass extinction, there is not a single species extinction that can be clearly attributed to the dingo. Maybe, just maybe, they contributed to the extinction of the Thylacine or Devil from the mainland, but the majority of ecologists accept that at worst they contributed to their demise by assisting human hunting. So that’s a grand total of two species at the most extreme. Not really amass extinction. > [@](#): > > .. that’s just an example on how inefficient the marsupials are when it comes to best-utilize the available resources. No, it’s an example of gross ignorance of the facts. I know the Victorian idea that marsupials are somehow inferior has held on longer than the idea that Black people are somehow inferior, but the two ideas have exactly the same roots and they both have the exact same evidence: none. Marsupials are objectively much more efficient than placentals when it comes to utilising resources. A kangaroo will live on about 75% of the amount of grass needed to feed an identically sized deer or antelope. A quoll will survive on just half the number of kills that would to feed a fox. An opossum needs about 2/3 the number of calories of a raccoon. Placental mammals are profligate energy users and incredibly inefficient. They are essential animal weeds. > [@](#): > > Marsupials simply are not competitive compared to placentals. In the real world we have three natural experiments: Australia, South America./Antarctica and the rest of the planet. In Australia marsupials dominated and placentals became completely extinct extinct. In south America, marsupials completely dominated the carnivore/omnivore niches and placentals were restricted to herbivory. In the rest of the world placentals became completely extinct. IOW we have seen the results of three natural experiments and the results are a perfect random spread. In terms of artificial experiments, we simply have to consider that for over 100 years there were attempts to introduce over 700 placental mammals species to Australia. A grand total of 12 managed to survive in the face of competition form the native marsupials. There is no justification of any sort for a claim that marsupials are not competitive with placentals. > [@](#): > > One example is how they utterly failed to effectively colonize the mountain ranges in Australia, while in other parts of the world where the condition on the mountain terrain is much harsher, the placentals still thrive (e.g. goat-antelope species, camellids, hyrax species, marmot species, carnivores such as puma and snow leopard). WTF? Firstly, what mountain ranges in Australia? Australia is the flattest continent on the planet. Mainland Australia only has one mountain range that is even detectable to the naked eye: the Great Divide. Even that disappears into a gentle slope for large parts of its length. There are a few isolated ranges of hills in the 400-1500m range, but they are insignificant geographically. Australia is incredibly flat. Secondly, and probably because of this, Australia is home to the greatest diversity of mountain adapted mammals _in the world._ There are over 20 different species of rock wallabies alone, compared to the single species of Mountain goat found in North America or the ten species of mountain ungulate found in Asia. I have no idea where you are getting this stuff from, but it is utterly incorrect. At best it is outdated by 50 years, but much of it has simply never been accepted by any ecologist anywhere > [@](#): > > From what you said though, it appears that the Southern Ungulates, are even less competitive, because they can’t even compete against the marsupials in Australia and became extinct there. Ahh, no. What I said was (and I quote) “marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica”. Ungulates could hardly become extinct in Australia when they never made it to Australia. But that is rather beside the point, because your whole thesis that marsupials are somehow uncompetitive has no basis in reality. ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 21, 2012, 2:17am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/11 "2012-06-21T02:17:32Z")
edited, retarded enter button ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 21, 2012, 2:37am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/12 "2012-06-21T02:37:54Z")
> [@griffon502](#): > > From what you said though, it appears that the Southern Ungulates, are even less competitive, because they can’t even compete against the marsupials in Australia and became extinct there. No wonder they got wiped out so quickly when the true ungulates from North America arrived with the land bridge. The southern ungulates (toxodonts and liptoterns) were not “wiped out so quickly” after the Panama land bridge formed. At least some of them co-existed with the northern ungulates for three million years or more. Toxodonts moved north as far a Mexico. The last surviving litoptern, _Macrauchenia_, became extinct only about 10,000 years ago. Both may have fallen victim to paleoindian hunters rather than competition with northern ungulates. It’s not clear that the decline of the marsupial carnivores of South America was directly due to competition with placental carnivores; they were already extinct before most of the placentals arrived from the north. While they may have suffered from competition with members of the raccoon family that arrived before the land bridge was complete, they also had to compete with the phorusrhacids, large flightless carnivorous birds, as well as opossums, which were fellow marsupials. See [here.](http://books.google.com.pa/books?id=LD1nDlzXYicC&pg=PA90&lpg=PA90&dq=borhyaenidae+pliocene&source=bl&ots=fyKdTiYEj_&sig=8b7FpGX6z0UQLChGzI3wtnhIzMw&hl=en&sa=X&ei=iYfiT5XXApSu8QT3v82GCA&sqi=2&redir_esc=y#v=onepage&q=borhyaenidae%20pliocene&f=false) ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 21, 2012, 3:16am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/13 "2012-06-21T03:16:35Z")
Ok Blake, it seems the ecological myths, combined with a false sense of Australian nationalism, have clearly clouded your judgement and made you unable to make objective judgement. You are simply biased against placentals. I tell you what, I care about the truths and the truths only. > [@](#): > > 1. Placentals arrived in Australia around 10 million years \*before \*the marsupials. They just didn’t arrive from South America. They were never common and they later became extinct. All this “evidence”, came from a SINGLE teeth. It is not substaintial. > [@](#): > > 1. Before humans arrived Australia had equal numbers of of placental mammals andd marsupials, just as it does today. Far from “some bats” Australia had huge numbers of species of bats and rodents. Australia had only 2 genera of bats, that is hardly “huge number”. And what the heck is the “equal” **number** you talking about? Species? Quantity? Without defining what “number” you are refering to the discussion would be pointless. You don’t seem to be able to talk in more scientific terms. > [@](#): > > No, it didn’t. Not only not a mass extinction, there is not a single species extinction that can be clearly attributed to the dingo. Maybe, just maybe, they contributed to the extinction of the Thylacine or Devil from the mainland, but the majority of ecologists accept that at worst they contributed to their demise by assisting human hunting. > > So that’s a grand total of two species at the most extreme. Not really amass extinction. In your mind, the imaginary early placentals got extinct due to over-competition from early marsupials, where is YOUR evidence then? How can you clearly contribute their disappearence to the marsupials? NONE. It is so obvious that you are biased against placentals. > [@](#): > > No, it’s an example of gross ignorance of the facts. > > I know the Victorian idea that marsupials are somehow inferior has held on longer than the idea that Black people are somehow inferior, but the two ideas have exactly the same roots and they both have the exact same evidence: none. Typical liberal/socialist mindset. Turning every debate into some politcal-correctness issue. Ever heard of Reductio ad Hitlerum? That’s excactly where your “arguments” are coming to. > [@](#): > > Marsupials are objectively much more efficient than placentals when it comes to utilising resources. A kangaroo will live on about 75% of the amount of grass needed to feed an identically sized deer or antelope. A quoll will survive on just half the number of kills that would to feed a fox. An opossum needs about 2/3 the number of calories of a raccoon. Oh really. How come rabbits became so rampant. How come camels, water bufflos, dingos, foxes and so on became so widespread to the point the Australian government had to intentionally try to exterminate them? I tell you what, it is well-known that ruminants are the most efficient herbivores due to their ability of ruminating. And deers DON’T feed on grass like kangaroos. Deers are mostly BROWSERS, not grazers. but clearly you have no idea such distinction even exists, judging by the fact you lumped them together. > [@](#): > > Placental mammals are profligate energy users and incredibly inefficient. They are essential animal weeds. Totally laugable eco-bargage, fed by marxist-eco professors. Just because placental MIGHT tend to use more energy does not make them inefficient. By your logic reptiles are more efficient as they use even less energy. You clearly do not understand what “efficiency” is about. And calling placentals “weeds”? How about you end your own life, you are placental yourself hence by definition you are weeds. And don’t eat beef, pork, lamb, milk any more. They are weeds. > [@](#): > > In the real world we have three natural experiments: Australia, South America./Antarctica and the rest of the planet. In Australia marsupials dominated and placentals became completely extinct extinct. In south America, marsupials completely dominated the carnivore/omnivore niches and placentals were restricted to herbivory. In the rest of the world placentals became completely extinct. Totally wrong. You have absolutely NO IDEA about the natural world. Seriously, since when did jaguar, mountain lion, tapir, racoon, coyote, deers, rodents and so on became marsupials? In SA, after the land bridge connected NA with SA, all marsupials got wiped out by placentals except the small-sized possum species. That was what would happen to Australia, if a similair event happened. > [@](#): > > In the rest of the world placentals became completely extinct I assume you meant marsupials. Otherwise this would be the most stupid statement I’ve seen in this forum. > [@](#): > > IOW we have seen the results of three natural experiments and the results are a perfect random spread. Only in your imaginary marsupial utopia, is it a perfect random spread. It is obvious that on all landmasses where marsupials and placentals compete, the marsupials got nearly wiped out, and in case they survives they only occupy very limited niches. > [@](#): > > In terms of artificial experiments, we simply have to consider that for over 100 years there were attempts to introduce over 700 placental mammals species to Australia. A grand total of 12 managed to survive in the face of competition form the native marsupials. Non-sense. There have never been so much introductions, and even if there were, most were very small-scale done by common people with little skills, and most were just for destination such as zoos and carnivals, hardly an “introduction” intended to establish viable, long-term population in Australia. And for the placentals that are present, they are remarkly successful. This is agreed upon by your fellow “ecologists” which is why they are so eager to exterminate them, because they think they out-compete and out-predate on the marsupials. > [@](#): > > WTF? > > Firstly, what mountain ranges in Australia? > > Australia is the flattest continent on the planet. Mainland Australia only has one mountain range that is even detectable to the naked eye: the Great Divide. Even that disappears into a gentle slope for large parts of its length. There are a few isolated ranges of hills in the 400-1500m range, but they are insignificant geographically. Australia is incredibly flat. > Secondly, and probably because of this, Australia is home to the greatest diversity of mountain adapted mammals _in the world._ There are over 20 different species of rock wallabies alone, compared to the single species of Mountain goat found in North America or the ten species of mountain ungulate found in Asia. The wallabies are hardly adapted to mountain life, compared to the mountain animals in other parts of the world. The environment they live in would be considered paradise for these mountain placentals in the outside world. And rock-wallabies are now declining due to competion from goats, sheeps,and rabbbits. This tells you a lot. > [@](#): > > I have no idea where you are getting this stuff from, but it is utterly incorrect. At best it is outdated by 50 years, but much of it has simply never been accepted by any ecologist anywhere I reach my conclusion through independent and logical thinking, rather than taking whatever garbage from the eco-marxist professors. And I have just shown you how incorrect you are. > [@](#): > > Ahh, no. What I said was (and I quote) “marsupials made it from South America to Australia via Antarctica, but South American placentals never made it past Antarctica”. Ungulates could hardly become extinct in Australia when they never made it to Australia. You have no idea what I was talking about, do you? First, this reply is irrevelant to my point, you are replying to something I never meant because you did not understand what I said. Second, you clearly have absolutely no idea what Southern Ungulates are, do some research before you speak. ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 21, 2012, 3:45am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/14 "2012-06-21T03:45:21Z")
> [@Colibri](#): > > It’s not clear that the decline of the marsupial carnivores of South America was directly due to competition with placental carnivores; they were already extinct before most of the placentals arrived from the north. While they may have suffered from competition with members of the raccoon family that arrived before the land bridge was complete, they also had to compete with the phorusrhacids, large flightless carnivorous birds, as well as opossums, which were fellow marsupials. The presence of large flightly carnovorous birds might as well be an indicator of the inefficiency of the marsupial carnivores. They became extinct shortly after the arrival of plancetal carnivores such as the true sabre-toothed cats. Gastornis, another genus of large, carnivorous birds, was apex predators in late Paleocene and Eocene in Europe and North America. But they went extinct when mamallians began to out-compete them. Taking from wikipedia. The mid-Eocene saw the rise of large creodont and mesonychid predators to ecological prominence in Eurasia and North America; **the appearance of these new predators coincides with the decline of Gastornis and its relatives.** This was possibly due to an increased tendency of mammalian predators to hunt together in packs (prevalent especially in hyaenodont creodonts). The\*\* fact that no birds appear to have ever weighed much more than half a metric ton suggests that they were restricted in their ability to evolve to larger and larger sizes, and thus in their ability to out-evolve apex predators by sheer bulk as mammals are often able to do\*\* (see Cope’s Rule). > **[Gastornis](https://en.wikipedia.org/wiki/Gastornis)** > > Gastornis is an extinct genus of large, flightless birds that lived during the mid-Paleocene to mid-Eocene epochs of the Paleogene period. Most fossils have been found in Europe, and some species typically referred to the genus are known from North America and Asia. Several genera, including the well-studied genus Diatryma, have historically been considered junior synonyms of Gastornis. However, this interpretation has been challenged recently, and some researchers currently consider Diatryma... The conclusion is, placental carnovivores were able to evolve to out-compete the large carnivorous birds. They first managed to do that in Europe and NA, then when the land bridge is formed, they did the same to the SA carnivous birds. Only this time it was even quicker because the mammal carnivores did not have to co-evolve with the SA birds to out-compete them. On the other hand, the marsupials failed to out-compete against the terror birds. The terror bird continued existence only proved that marsupials were inefficient, in-competent predators, compared with placentals. ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 21, 2012, 4:03am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/15 "2012-06-21T04:03:53Z")
I just want to add a point. It’s not just the mountain species, or the carnivores, even the ant-eating marsupials are inefficient compared to the placentals. The numbats simply “suck” compared to the placental ant-eaters. They have the least skills when it comes to survival and ant-eating. They fail in almost EVERY category. Only “advantage” is maybe they look the cutest ant-eater so I would have no problem owning one as a pet. 1. ability of foraging The numbats, according to wiki, do not have claws that are “strong enough to get at termites inside their concrete-like mound, and so must wait until the termites are active”. Almost all other ant-eaters do. Pangolins, aardvak, and Amercain ant-eaters, all powerful enough to do that. 1. protection against predator Numbats are suffering because of RED FOXES, I mean, seriously, red foxes… small-sized canine species have never been a problem for other ant-eaters. In addition, numbats are UN-ARMORED, and cannot dig quickly. Heck, even the Echidna got spines which protect them from predators, and they are mono-tremes… It’s pathetic that numbats are only able to survive because of protection from human. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 21, 2012, 4:30am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/16 "2012-06-21T04:30:19Z")
> [@griffon502](#): > > The presence of large flightly carnovorous birds might as well be an indicator of the inefficiency of the marsupial carnivores. They became extinct shortly after the arrival of plancetal carnivores such as the true sabre-toothed cats. Cite? The Borhyaenidae is generally considered to range to [about 5 million years ago](http://museumu03.museumwww.naturkundemuseum-berlin.de/cgi-bin/bridge.pl), that is, before the Panama land bridge became complete and before most placental carnivores reached South America. Smilodon originated about 2.5 million years ago. I am not aware that any other sabre-toothed genera reached South America. > [@](#): > > Gastornis, another genus of large, carnivorous birds, was apex predators in late Paleocene and Eocene in Europe and North America. But they went extinct when mamallians began to out-compete them. Some Phorusrhacids were able to compete with placental carnivores, for example [_Titanis_](http://en.wikipedia.org/wiki/Titanis) of Florida, which coexisted with them for a good 3 million years. > [@](#): > > The conclusion is, placental carnovivores were able to evolve to out-compete the large carnivorous birds. They first managed to do that in Europe and NA, then when the land bridge is formed, they did the same to the SA carnivous birds. Only this time it was even quicker because the mammal carnivores did not have to co-evolve with the SA birds to out-compete them. > > On the other hand, the marsupials failed to out-compete against the terror birds. The terror bird continued existence only proved that marsupials were inefficient, in-competent predators, compared with placentals. This is a very simplistic view. There is no real evidence that the South American carnivores became extinct because of competition by placentals. As I said, they declined long before major carnivore groups even reached South America. ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 21, 2012, 5:01am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/17 "2012-06-21T05:01:19Z")
I found a related discussion here: > **[Why do placentals win?](https://ask.metafilter.com/121362/Why-do-placentals-win)** > > Why is it that placentals outcompete marsupials when they're in the same ecosystem? Here are some important posts supporting my opnion: > [@](#): > > Every time bioenergy is converted to edible matter and then eaten and digested, there is a huge energy loss. For a given mass of plant matter- by the time it winds up as blood glucose in a first order consumer - perhaps 80% of the energy the plant had used is gone. When that herbivore winds up in the blood of its predator, there has been a similar energy loss. > > The production of marsupial milk is bioenergetically costly, as is the digestion of it within the fetus’ belly. Conversely, a placental mother wastes no energy passing nutrients to baby. **All other things being exactly equal, placentals will displace marsupials in short order as has been demonstrated by all placental imports to Australia conducted by people**. > > YIFIAABE (yes, in fact I am a behavioral ecologist). > [@](#): > > Ironmouth, while Chocolate Pickle did indeed use the term “superior”, the original phrasing was “outcompete” - and it would be hard to argue that placental mammals didn’t outcompete marsupials on 6/7 continents. > > We do not know what would happen if large numbers of animals from each group were to compete with one another. > > We do. **It was during the Cenozoic/Pleistocene changeover. Marsupials were displaced from almost all ecological niches by placentals, everywhere they coexisted**. ---
**Author:** ![griffon502](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@griffon502](https://boards.straightdope.com/u/griffon502)\ **Post date:** [June 21, 2012, 5:08am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/18 "2012-06-21T05:08:17Z")
> [@Colibri](#): > > This is a very simplistic view. There is no real evidence that the South American carnivores became extinct because of competition by placentals. As I said, they declined long before major carnivore groups even reached South America. How do you know? Moreover, even if it did happen, the placentals did not seem to be affected much, which in turn would suggest they were more adaptable. What I think is, marsupials and placentals lived alongside with each other for millions of years during the dinosaur age. But once the dinosaurs were gone, the mammals were able to diversify quickly, and the placental were simply superior to marsupials and replaced them everywhere except isolated places like SA and Australia, and the marsupials in SA got wiped out when the placentals arrived. The earliest marsupial fossil is found in China. The second oldest is from Mongolia. > **[National Geographic](https://www.nationalgeographic.com/)** > > Explore National Geographic. A world leader in geography, cartography and exploration. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 21, 2012, 5:13am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/19 "2012-06-21T05:13:40Z")
That last comment [in post #17] is incorrect. You can’t consider that there are 7 independent “experiments,” but as **Blake** says, only three. Europe/Asia/Africa/North America have been effectively one land mass for most of the Cenozoic (the “World Continent”, while Australia and South America were isolated island continents. Placentals dominated the World Continent, marsupials Australia, and South America had marsupial carnivores and placental herbivores. (We don’t know much about Antarctica.) If there is a competitive advantage, it is between animals that have evolved on larger land masses have an advantage over those from smaller landmasses. If animals from the World Continent have an advantage over those from the island continents, it’s likely due to the fact that they come from a larger land mass. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [June 21, 2012, 5:21am UTC](https://boards.straightdope.com/t/antartican-organisms-extinct/625686/20 "2012-06-21T05:21:03Z")
> [@griffon502](#): > > How do you know? Moreover, even if it did happen, the placentals did not seem to be affected much, which in turn would suggest they were more adaptable. How do you know? Like I said, your view is largely speculation and is not strongly supported by any real evidence. [QUOTE=griffon502] the marsupials in SA got wiped out when the placentals arrived. [/QUOTE] As I said, this is simply incorrect. Stop repeating it unless you can produce some evidence that it’s actually true. First of all, marsupials did not get “wiped out.” Opossums are diverse and widespread in the Americas, with over 100 species in the Americas in various ecological niches, and one is even common in North America. Second, the marsupial carnivores in South America became extinct well before the arrival of most placental carnivores, so their demise can’t be attributed to that. [Next page](https://boards.straightdope.com/t/antartican-organisms-extinct/625686.md?page=2)