# Why are all the marsupials in Australia? **URL:** \ **Category:** Factual Questions\ **Created:** [November 17, 2005, 4:33pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501 "2005-11-17T16:33:27Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Birdmonster](https://avatars.discourse-cdn.com/v4/letter/b/71e660/32.png) [@Birdmonster](https://boards.straightdope.com/u/Birdmonster)\ **Post date:** [November 17, 2005, 7:31pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/21 "2005-11-17T19:31:17Z")
> [@Duckster](#): > > Pandas and marsupials are mammals. Marsupials are just a weird version of mammals. I know. I was responding to a post that inplied pandas were marsupials, which they ain’t. Rectangles & squares, you know. ---
**Author:** ![MelCthefirst](https://avatars.discourse-cdn.com/v4/letter/m/eada6e/32.png) [@MelCthefirst](https://boards.straightdope.com/u/MelCthefirst)\ **Post date:** [November 17, 2005, 7:34pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/22 "2005-11-17T19:34:48Z")
> [@Giles](#): > > Not as wierd as monotremes (which are only found in Australia and New Guinea). > As I said above, there are many different kinds of rodents and bats in Australia, which have been there for a long time and show no signs of dying out. > [The Australian Museum on Australian mammals](http://www.amonline.net.au/mammals/about/) Sorry, I meant large placental mammals that are no longer on the Australian continent - I think they were some kind of deer. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 17, 2005, 7:44pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/23 "2005-11-17T19:44:21Z")
> [@Birdmonster](#): > > I know. I was responding to a post that inplied pandas were marsupials, which they ain’t. Rectangles & squares, you know. I was misinformed. ---
**Author:** ![Birdmonster](https://avatars.discourse-cdn.com/v4/letter/b/71e660/32.png) [@Birdmonster](https://boards.straightdope.com/u/Birdmonster)\ **Post date:** [November 17, 2005, 7:58pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/24 "2005-11-17T19:58:21Z")
As was I (see thread title). Actually, it wasn’t so much misinformed as it was a blind, idiotic, early morning assumption. ---
**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:** [November 17, 2005, 8:47pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/25 "2005-11-17T20:47:17Z")
> [@Birdmonster](#): > > Apparently marsupials mommies have two vaginas. This is confusing to poor birdmonster this morning. My God! Males have two dicks! Lesser evolved, my ass! Actually, female marsupials have not one, not two, but three, count 'em, three vaginas. The two lateral vaginas receive the bifurcated penis of the male. The medial vagina, between the other two, does not develop until the female gives birth. Females that have given birth retain all three vaginas, at least in kangaroos. I swear a diagram of the female marsupial reproductive system looks like a map of the Times Square subway station. ---
**Author:** ![FordPrefect](https://avatars.discourse-cdn.com/v4/letter/f/e99b99/32.png) [@FordPrefect](https://boards.straightdope.com/u/FordPrefect)\ **Post date:** [November 17, 2005, 9:02pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/26 "2005-11-17T21:02:13Z")
> [@Johnny L.A.](#): > > Pandas live in China. Maybe it is my head cold or just my evilness, but this is one of the more pleasantly surreal and amusing interjections I have read here in a while. All I can imagine is a 7 year old kid pumped with new knowledge putting up her hand and saying, “Pandas live in China!” to an exasperated elementary teacher. I really do hope you are not offended at my amusement. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [November 17, 2005, 9:04pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/27 "2005-11-17T21:04:52Z")
> [@Johnny L.A.](#): > > I was misinformed. I believe you were thinking of the American Bison–the largest of all marsupials not yet extinct. The prize for largest marsupial of course, goes to the giant 4-toed Asian ground sloth. > [@Giles](#): > > Not as wierd as monotremes (which are only found in Australia and New Guinea). Don’t forget the Mountain Gorilla of Africa–black market pressure for their eggs are driving them to extinction. Tragic. ---
**Author:** ![Birdmonster](https://avatars.discourse-cdn.com/v4/letter/b/71e660/32.png) [@Birdmonster](https://boards.straightdope.com/u/Birdmonster)\ **Post date:** [November 17, 2005, 9:32pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/28 "2005-11-17T21:32:00Z")
> [@Inigo Montoya](#): > > I believe you were thinking of the American Bison–the largest of all marsupials not yet extinct. The prize for largest marsupial of course, goes to the giant 4-toed Asian ground sloth. > Don’t forget the Mountain Gorilla of Africa–black market pressure for their eggs are driving them to extinction. Tragic. The greatest thing is, I have no idea if you’re being serious. My biology teacher is rolling in her grave, except she probably isn’t dead. ---
**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:** [November 17, 2005, 9:43pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/29 "2005-11-17T21:43:15Z")
> [@jrfranchi](#): > > In fact from what I have read, they are more closely related to Racoons than Bears. That used to be what was thought, but now it is generally believed that Giant Pandas are in fact a kind of bear. Lesser Pandas are thought to be closer to racoons (though I believe this may still be somewhat up in the air). ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [November 17, 2005, 9:51pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/30 "2005-11-17T21:51:17Z")
> [@Birdmonster](#): > > The greatest thing is, I have no idea if you’re being serious. My biology teacher is rolling in her grave, except she probably isn’t dead. All lies. I’m so ashamed… ☹ ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [November 17, 2005, 10:27pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/31 "2005-11-17T22:27:17Z")
> [@Johnny L.A.](#): > > I was misinformed. Don’t move to Casablanca for the waters, **Johnny**. 😉 Methinks you were probably thinking of the koala “bear”, which isn’t a bear but a slow-moving, irritable, eucalyptus-eating marsupial. The Giant Panda (_Ailuropoda melanoleuca_) are most certainly bears (family _Ursidae_), although their dietary habits and ecological niche vary widely from the American and Asiatic Black Bears with which people are most familiar. There is some debate as to whether the Red (or Lesser) Panda belongs in _Ursidae_ or _Procyonidae_ (the raccoons, coatis, and onlingos); as a result, they’ve been classed in their own intermediate family, _Ailuridae_, of which they are the solitary member. Their most common feature, other than overlapping habitats, is that both have a “false thumb” formed from an extended wrist bone (which helps in stripping bamboo, which is a stable of their diets), but the Giant Panda is most closely related to the Spectacled Bear, while the Red Panda is closer to raccoon or badger. > [@Polycarp](#): > > There used to be a hypothesis that the placentals dominated because of an inherent advantage to placental reproduction over marsupial, but the actual case seems to be that the placentals, faced with more competition in the larger area, tended to evolve into forms better adapted to the niches that converged with those of the marsupials. The dingo, for example, is no better physiologically at predation than a thylacine, but it’s a smarter animal. Well, it may or may not be smarter–given that we have, at this point, only anecdotal evidence of the intelligence of the thylacine we can only speculate–but two advantages that _Canis lupus dingo_ (which should more properly be _Canis familiaris dingo_, IMHO) had over the thylacine is that is moves faster and hunts in packs, allowing the pack to take larger prey than a single animal can handle. The thylacine (sometimes called the Tasmanian or Marsupial Wolf but more analogous to the large cats) suited pursued prey with a slow, loping gate for long distances until it overcame by endurance, then used its enormous, wide angle jaw to crush its prey’s head or throat. In comparison, a dingo pack will attack and nip at prey, guiding it back toward other pack members to bring it down in quick order. It doesn’t help, of course, that Austrailian farmers and ranchers prosecuted a campaign to eradicate the thalycine as a danger to sheep and cattle herds which cattle dogs couldn’t always repel. In general, in like comparisons marsuipials seem to have lower birthrates and higher infant mortality than placental mammals. (It is sometimes claimed that marsupials are a more primitive mammalian form, but I don’t know that one can make that statement baldly; the black bear is sort of an “intermediate form” which has placental birth but an extremely low birth weight and development during hibernation, and it is hardly a primative mammal.) Marsupials developed prevelently in Australia for the same reason a small number of species diverged and “filled up” ecological niches in the Galapagos; because they were isolated from other animals, and developed to be only so fast or effective as necessary to maintain their status within that isolated ecosystem. When confronted with a different competitor, the system comes to a new equilibrium. It’s not that one is “more advanced” than the other in an objective sense, but rather which exhibits more effective behaviors and predatory abilities in the common environ. Stranger ---
**Author:** ![Birdmonster](https://avatars.discourse-cdn.com/v4/letter/b/71e660/32.png) [@Birdmonster](https://boards.straightdope.com/u/Birdmonster)\ **Post date:** [November 17, 2005, 10:35pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/32 "2005-11-17T22:35:40Z")
> [@Inigo Montoya](#): > > All lies. I’m so ashamed… ☹ This entire day has been an excercise in personal embarrassment. I thank you for contributing. Birdmonster’s new rule of thumb: If you’re talking to a guy who thinks that a bison might actually be a marsupial, it’s time to stop talking to that guy. I’ll shut up now. ---
**Author:** ![TheLoadedDog](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TheLoadedDog](https://boards.straightdope.com/u/TheLoadedDog)\ **Post date:** [November 17, 2005, 10:41pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/33 "2005-11-17T22:41:04Z")
> [@Colibri](#): > > Actually, female marsupials have not one, not two, but three, count 'em, three vaginas. The two lateral vaginas receive the bifurcated penis of the male. The medial vagina, between the other two, does not develop until the female gives birth. Females that have given birth retain all three vaginas, at least in kangaroos. I swear a diagram of the female marsupial reproductive system looks like a map of the Times Square subway station. So kangaroo males can navigate all this, but Australian human males still have problems finding a clitoris? Kinda embarrassing being upstaged like that. 😃 ---
**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:** [November 17, 2005, 11:11pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/34 "2005-11-17T23:11:27Z")
> [@Stranger On A Train](#): > > It is sometimes claimed that marsupials are a more primitive mammalian form, but I don’t know that one can make that statement baldly; It was once assumed that marsupials were more “primitive” than placentals, but the two groups are of similar antiquity in the fossil record. Marsupials did not precede placentals, and as far as we know placentals did not go through a stage in which their reproduction was similar to that of marsupials. The two groups simply have different reproductive strategies, and that of marsupials is not inherently inferior to that of placentals. > [@TheLoadedDog](#): > > So kangaroo males can navigate all this, but Australian human males still have problems finding a clitoris? Kinda embarrassing being upstaged like that. Now you have me wondering how many clitorises female marsupials have . . . ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 17, 2005, 11:25pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/35 "2005-11-17T23:25:20Z")
> [@Stranger On A Train](#): > > Don’t move to Casablanca for the waters, **Johnny**. 😉 > > Methinks you were probably thinking of the koala Ha! One of my favourite films! 🙂 No, I was thinking of the panda. I could have sworn it was a marsupial. I was wrong. I’m embarassed, but Ignorance has been fought. :o ---
**Author:** ![Laughing\_Lagomorph](https://avatars.discourse-cdn.com/v4/letter/l/6bbea6/32.png) [@Laughing\_Lagomorph](https://boards.straightdope.com/u/Laughing_Lagomorph)\ **Post date:** [November 17, 2005, 11:56pm UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/36 "2005-11-17T23:56:06Z")
I remember reading recently the hypothesis that the marsupial reproductive system in general was better suited to harsher environments. If, for example, there was a drought (not uncommon in Australia, historically speaking) and a female kangaroo lost her offspring because of it it was less of an issue because marsupials invest relatively less resources in a given pregnancy than placentals do. This would make it easier to have young quickly again when the drought ended. Reading the above I realize I am (once again) having trouble saying what I want clearly. The point of this article (can’t remember where I read it) was that there might be inherent features of the environment of Australia that made the marsupial set-up a more succesful reproductive strategy there over the long haul, while the placental strategy seemed to be more succesful pretty much everywhere else. The author(s) of the article were specifically trying to account for the success of marsupials in Australia when there have in fact been placentals (like the aforementioned rodents and bats) there for quite some time. ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [November 18, 2005, 1:23am UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/37 "2005-11-18T01:23:01Z")
> [@Lemur866](#): > > Of course, in 20 million years Australia is due to crash into southeast Asia anyway and will then have a permanent land bridge with the rest of the continents. Brace, brace, brace! ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [November 18, 2005, 1:26am UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/38 "2005-11-18T01:26:42Z")
> [@Princhester](#): > > Brace, brace, brace! Australian foreplay? ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [November 18, 2005, 1:57am UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/39 "2005-11-18T01:57:47Z")
> [@Inigo Montoya](#): > > Australian foreplay? I believe that would be “chunder, chunder, chunder” 😉 I’m wondering why your collection of unusual marsupials didn’t include the [Hotheaded Naked Ice Borer](http://www.museumofhoaxes.com/tall-tales/antarctic-ice.html), Antarctica’s only land mammal. 🙂 ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [November 18, 2005, 2:17am UTC](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501/40 "2005-11-18T02:17:17Z")
OK, that’s not funny. I SO believed that article when it first came out. Told all my (astounded) friends about it and everything. [Previous page](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501.md?page=1) [Next page](https://boards.straightdope.com/t/why-are-all-the-marsupials-in-australia/331501.md?page=3)