Marsupials are very similar to placental mammals, but differ in how they reproduce. Most marsupials lack a placenta, so they are unable to feed their offspring in the womb. Instead, after only a few days of gestation, their young must crawl out of the womb to feed from a nipple inside the mother’s pouch. (Thank god we humans don’t give birth this way, I can’t imagine any woman would want baby fetuses crawling out of her nether regions. Creepy. Although… come to think of it… the current method really isn’t all that great, either.)
What’s also intriguing about marsupials is where they’re located. There are 334 known species of marsupials; 70% live in and around Australia, 28% live in South America, and 2% live in Central and North America.
But looking at the map below, we can see that marsupials make their homes about as far away as you can possibly get from the Middle East, where Noah’s Ark would’ve settled.
What’s also interesting is that there are no truly native placental mammals in Australia. How did all these marsupials manage to pull off such a long and segregated migration? Secular science and Creationists offer two very different explanations, let’s take a look at both.
The Secular View
Fossil evidence suggests that the earliest marsupials originated in China and then became quite common in North America (even outnumbering mammals, for a time). As their numbers dwindled in North America, they began to thrive in South America. Most of the marsupials that remain in the Americas today are from the opossum family (didelphidae).
Scientists say that millions of years ago, our earth was a very different place. Back then, Australia was connected to South America by way of Antarctica. Scientists theorized that a small number of marsupials must’ve found their way from South America, across Antarctica, and up into Australia. The eventual discovery of marsupial bones in Antarctica all but confirmed this suspicion.
For years and years people thought marsupials had to be there, this ties together all the suppositions made about Antarctica. The things we found are what you’d expect we would have.
~ Dr. William J. Zinsmeister, Paleontologist at Ohio State University’s Institute of Polar Studies
More recent evidence from retroposon markers in DNA also suggests that all Australian marsupials descended from South American ancestry.
Other plant and animal fossils found in Antarctica match up with those found in Australia and South America, strongly suggesting that not only were these continents once connected, but that Antarctica once enjoyed a much warmer, tropical climate.
Roughly 35-50 million years ago, Antarctica wished Australia “bon voyage” and it slowly drifted away toward the equator. The Australian rain forests gave way to extensive grasslands, and the marsupial stowaways spent the next few million years in isolation, learning to survive in the new ecological niches that Australia offered.
Most palaeontologists agree that Metatheria originated in Asia, diversified throughout the northern continents, dispersed into Gondwana (the modern Southern Hemisphere) around the beginning of the Palaeocene epoch (65 million years ago), then moved through Antarctica to Australia before the Australian continent was isolated by the opening of Drake Passage between South America and Antarctica.
~Bennett, Verity. 2012. Fossil Focus: Marsupial evolution – A limited story? Palaeontology Online, Volume 2, Article 10, 1-9
Today there are far more species of marsupials in Australia than in South America, and it’s believed that this is due to changing environments and a lack of competition from other mammals.
The Creationist View
Creationists have a largely different view. They believe a global flood wiped out all mammals except for those aboard Noah’s ark.
While Creationists believe the landscape of the earth may have changed dramatically during the flood, most don’t believe that the earth has changed much since then. This means marsupials would’ve had to cross multiple bodies of water in order to reach Australia and South America. To bridge these gaps, Creationists suggest an ice-age occurred soon after the flood.
This ice age lowered sea levels and could’ve created a land bridge between Asia and Australia. To the north, another land bridge may have crossed the Bearing Strait (between Russia and Alaska), allowing for some marsupials to cross over the frozen landscape (hopefully without becoming tiny, frozen, “marsupcicles” in the process).
To explain the complete absence of placental mammals in Australia, creationists speculate that because marsupials can carry their young, this allowed them to outpace all placental mammals. All Australian marsupials crossed the land bridge before rising waters (and possible earthquakes) caused the land bridge to disappear forever.
When a marsupial has its young, they can hop into the mother’s pouch, and the mother can continue migrating. In other words, marsupials can travel farther faster than many placentals.
~Bodie Hodge, Answers in Genesis – June 8, 2012
So who is correct?
Obviously, these explanations are very different. Let’s take a closer look at some of the more debatable points.
Both Creationists and secular scientists believe in ice ages, and that there was once a land bridge across the Bearing Strait. But few (if any) scientists believe that water levels dropped low enough to create a land bridge between Asia and Australia during the “Last Glacial Period.”
Part of the reason is that there are deep trenches where subduction divides these continents. This tectonic border would likely prevent any land bridges from fully forming. Creationists counter this by suggesting that earthquakes may have since changed the landscape or made these trenches deeper, or that marsupials found other, more creative, ways to get across…
“In some cases, animals could have ridden on floating debris to make it to islands or other far-reaching places.”
~Bodie Hodge, Answers in Genesis – June 8, 2012
How did all the marsupials get their first?
Assuming a land bridge existed, how did all marsupials arrive in Australia ahead of all placental mammals?
Marsupials can carry their young, which allows them to avoid having to stop to care for them, but some mammals are born with the ability to walk — and even run, and some marsupials would’ve made for extremely slow travelers.
The southern marsupial mole, for example, spends most if its life underground… and it has no eyes. Did it blindly burrow its way to Australia?
The koala bear is another good example. It sleeps or rests 22 hours a day (and my wife thinks I’m lazy) and is completely arboreal (lives in trees). When it’s not resting, it’s busy filling up on yummy eucalyptus leaves (which are indigenous to Indonesia and Australia, but that’s another issue).
It’s hard to imagine that these slow, blind marsupials could’ve managed such a migration, let alone beat every single placental mammal to boot! (Especially when you consider that placentals outnumber marsupials 15 to 1). What’s also amazing is that not a single marsupial stayed behind — they all migrated away from the Middle East.
How did this happen?
It’s almost as if all marsupials traveled together in a group. Perhaps one marsupial, I imagine it would’ve been the kangaroo (because they’re obvious natural leaders), stood up after the flood and said, “Alright mates, listen up! I want everyone with a pouch to line up over here. God wants us to go on a walkabout to the ends of the earth, so that means there will be no settling anywhere in Africa, Europe or Asia. Got that? Also, some of us are much slower than others… or completely blind… so we may need to carry these guys on our backs or in our pouches.”
Perhaps, when they’d traveled as far as Mongolia, the kangaroo announced, “The God of Abraham has sent an ice age so that we may finish our journey. Some of the opossums will head north, across the Bearing Strait, and down through Canada, and into the Americas.” (Of course, these places didn’t actually go by these names back then, but I’m not exactly sure what the kangaroos would’ve called them — don’t laugh, if the Bible can have talking snakes and donkeys, this trip may have called for a talking kangaroo.)
The kangaroo continued: “It’s going to be a long, cold, arduous journey with weather like you’ve never seen, so make sure you dress warm and have a snow buddy. The rest of us will head down to Australia ahead of all the mammals, before the snow melts. We will never see each other again, so ladies and gentlemarsupials, I want to say what an honor it’s been making this journey with you.”
The Fossil Record
There is no evidence that modern Australian marsupials (like kangaroos, koalas, and wallabies) ever existed in Europe and Asia. Creationists reason that just because we don’t find fossilized remains, doesn’t mean they were never there. They acknowledge that it’s rare for fossils to form, and insist that the absence of fossil evidence does not disprove their theory. (Wait… why does this all sound so familiar?)
When we think with a Biblical perspective, we realize that all kinds of land animals must’ve once lived in the Middle East, because they came with Noah’s ark.
~ Ken Ham, President Answers in Genesis, USA
Meanwhile, scientists made an almost equally absurd claim that marsupials must’ve lived in Antarctica… and they were right!
But evolution can also seem like a leap of faith, because we can’t see it happening. How does something like an opossum morph into something as different as a koala bear, a wallaby, or a kangaroo?
While scientists might rely on things like fossils and genetic evidence, this evidence cannot be readily observed by the layman, like myself. I’m more comfortable with evidence I can actually see.
In the case of marsupials, some of that observable evidence comes from similarities in their features, such as the trademark pouch. Another thing that’s readily observable is that all these similar animals live in the exact same isolated neighborhood.
While marsupial transitional forms may be long gone (even Creationists admit fossils are difficult to find), when I look at the marsupials that exist today, I can see the family resemblance (see images below).
The brown dorcopsis, for example, looks like a small wallaby, and the wallaby looks like a small kangaroo. And the tree kangaroo, with its long tail, looks like the lovechild of a kangaroo and a koala.
Considering their isolation and similarities, I feel I can safely conclude that these animals must be related. While it’s reassuring that other lines of scientific evidence confirm this relationship, we don’t need this evidence to make our initial observation.
We could suggest that God performed some form of miracle — perhaps magically transporting all these mammals. But if that’s true, why didn’t He transport any placental mammals? And why deceive us with the impression that these similar animals must’ve evolved on this island?
The natural evidence suggests one story, the Bible another. While I really am willing to accept the flood account, I must insist that it be accompanied by some respectable evidence. If we didn’t have the Bible, there’s just no way we’d conclude that Australian marsupials emerged from the Middle East.
Because we only find these unique marsupials in Australia, I’d have to conclude that the most logical explanation is that this is where they all originated.
While the prospect of their evolution may be difficult to accept, is it really any less absurd than believing an ancient man built a ginormous boat and filled it with two of every animal on earth? Or that all marsupials (including the slow and the blind) hiked their way from the Middle East to Australia, across a non-existent land-bridge, together, ahead of all placental mammals?
Think what the geographical distribution of animals should look like if they’d all dispersed from Noah’s Ark. Shouldn’t there be some sort of law of decreasing species diversity as we move away from an epicentre — perhaps Mount Ararat? … Why would all those marsupials – ranging from tiny pouched mice through koalas and bilbys to giant kangaroos and Diprotodonts — why would all those marsupials, but no placentals at all, have migrated en masse from Mount Ararat to Australia? Which route did they take? And why did not a single member of their straggling caravan pause on the way, and settle — in India, perhaps, or China, or some haven along the Great Silk Road? … Why would an all-powerful creator decide to plant his carefully crafted species on islands and continents in exactly the appropriate pattern to suggest, irresistibly, that they had evolved and dispersed from the site of their evolution?
~Richard Dawkins, The Greatest Show on Earth: The Evidence for Evolution, 2009, pp. 268-270