I was thinking about how there are some instances of convergent evolution between marsupials and placental mammals and was thinking about a parallel universe in which there is convergent evolution between marsupials and humans. In this universe a species of marsupial evolves at about the same time as humans to have the same intelligence as humans as well as walking upright on two legs. The humanoid marsupial knows how to control fire, use throwing spears for hunting, use stone tools, paint, and make boats. The humanoid marsupial originates in Australia but begins spreading beyond Australia at the same time that Homo Sapiens are spreading out of Africa. As Homo Sapiens and Humanoid Marsupials are spreading they meet in India

How would the humanoid marsupials and homo sapiens interact after coming in contact with each other?

  • $\begingroup$ Given that as soon we figured out "they are different than us" and "we can get their dinosaur chop" we started banging others on the head... $\endgroup$ Commented May 4, 2016 at 20:43
  • $\begingroup$ Koala people or kangaroo people?! What sort of marsupial are you considering? The former definitely would not do very well compared to humans, the latter probably would. $\endgroup$
    – user20787
    Commented Jun 7, 2016 at 16:03

3 Answers 3


This is all speculative, but given the scenario, neither species would be able to completely wipe out the other, seeing how far away the origin of either one is from the other. Ultimately, both sapiens would need to develop alongside each other.

Early humans weren't very intelligent. I'm talking about Homo Sapiens here. Even with the capacity for higher thinking, they weren't too different from other animals, with only a very primitive language and grasp on tools, and they would be extremely territorial. Assuming human migration up to the point they meet is largely the same, the two species would have met in India between 80,000 and 120,000 years ago.

There are signs that Homo Sapiens and Homo Neanderthalensis (Neanderthals) weren't always on the best of terms, and probably cannibalized each other, like AndreiROM mentions, but the same is true for any differing tribe of Homo Sapiens, too. The appearance and similarities between two tribes didn't really factor in, and it was just a tribe mentality, similar to how modern day humans often still prefer their own race or country over another. Humans and Neanderthals also have left evidence that not all of their interactions have been violent. Depending on how your marsupial sapiens look and act, it's possible that the primate sapiens (humans) could either eventually develop some sort of mutual relationship, or all together try to eliminate each other—but it ultimately depends on the amount of resources. Considering the marsupials would come from Australia, it wouldn't be feasible for homo sapiens to outright eliminate them though.

Assuming that both sides survive first contact and there is a sizable population of marsupial sapiens on the Eurasian continent, the primate sapiens would go on to populate Europe and west Asia, while our marsupials could possibly hold onto East Asia, and even be the ones to migrate into the Americas, assuming there were similar pressures as in our own timeline. The separation probably won't be so clean, and there'd be tribes of both mixed in either region, which could either end up wiped out or tolerated long enough to develop.

If and when tribal societies evolve into more stable villages and cities, is probably when you can expect the relationship from both species to be much less extreme. There is the issue that the Silk Road might not actually exist, because even if both sides aren't constantly trying to eat each other, they still might not like each other enough to trade. This means that the benefits Europe had over Asia and the rest of the world (that eventually led to military domination), may not develop in the same way, and technological progress may stagnate for quite a while. The Black Death probably also won't happen in the same way that it did because diseases between the two species would rarely be compatible, so assuming Europe faces the same issues it was facing in our own timeline, they probably won't have the same dark miracle that reduced their population by so much and allowed the age of enlightenment to kick start.

Taking that into account, if Europe ever decided to cross the Atlantic, the Marsupials living in the Americas wouldn't suffer the same destruction by disease as the Native Americans did in our timeline.

What might happen with the marsupial sapiens that inhibit Australia and Asia? I can't tell. I don't know what sort of temperament they hold compared to humans, what sort of language they would develop, and so on. My assumptions on Europe are based on the idea that it would mostly be inhabited by humans, and there would be a pretty big buffer between them and the marsupials. However, it's easily likely that over time the Eurasian continent had both species mix around less cleanly than what my scenario implies. After all, it's not really likely that there'd be a hard wall between where one group or the other lives.

There are many different ways this scenario could play out, as you further advance their technology. There's also the issue of religion, and how the religion of one race would view the other, and what effect that would have on the future relations. There's no definite answer to this question, because we only have a sample size of 1 sapient animal.


Well, this is pure speculation, but considering that Homo Sapiens and Neanderthals mostly (not always, but often) slaughtered one another (and they were cousins), not to mention man's treatment of other men throughout history, I would say that the only realistic interaction would be war.

The humans would probably fail to realize that the marsupials are "sapient" (and would probably not care even if they knew - moral concerns were not big on the list of our ancestor's list of things to worry about) and maybe even hunt them for food. Cannibalism is definitely something which a lot of cultures participated in, so it's not a stretch that they would eat other sapient species.

As species they would probably fight over resources, and generally slaughter one another. Every once in a while individuals of these races might meet under circumstances in which they would not immediately try to kill one another, and maybe, over time, some understanding could be come to.

Remember that back then humans didn't speak a language - more of a proto-language. Grunts, gestures, etc. This will make it difficult for two species with very different emotional responses and expressions to communicate.


Marsupials could never have evolved to have human-like intelligence/sapience, because of how the brain development of mammalian fetuses and infants works.
Human babies are born with huge but still very immature brains, and they really need both the pregnancy to grow that much brain mass and the lengthy childhood to mature it. I can't see a newborn marsupial, with the characteristic tiny size compared to its mother, either already having a sufficiently large brain, or growing it later in the pouch. Being protected and warmed and receiving milk is a nice thing, and also both necessary and sufficient for a smaller-brained marsupial to grow up, but the delicate work of growing a large brain requires the additional help of having one's oxygenation and immune system taken care of.

Same reason that there are limits to the brain size and therefore the intelligence of birds, because they need to secure the brain oxygenation while in egg.

The thing about bird chicks is from Human Evolutionary Biology by Arndt von Hippel, and I don't remember where I got the idea that marsupial brains are restricted in size, probably something I learned around the same time as I heard about the concept of neoteny, many years ago. Little search on the topic turned out a paper that claims there is not much difference between marsupials and non-primate placental mammals, because apparently most brain growth in marsupials occurs during lactation... http://www.pnas.org/content/107/37/16216.full

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    $\begingroup$ Can you add some citation links to that? Very interesting idea. $\endgroup$
    – JDługosz
    Commented Jun 7, 2016 at 9:21

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