Kangaroos, koalas, wombats, and Tasmanian devils belong to a special group of mammals called marsupials. Marsupials carry their young in pouches on their belly until they are big and strong enough to walk (or hop!) on their own. But you’re not likely to find a kangaroo hopping through the woods near your house, or a Tasmanian devil cleaning up roadkill along the interstate. That’s because they’re endemic, meaning that they are found in only one place on the planet. Their home, sweet home? Australia, the Land Down Under, mate! True, some marsupials do live in other places, like North America’s own Virginia Opossum, but two-thirds of all marsupials live only in Australia.
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This might sound confusing to a young-earth creationist. We know from Scripture that the global Flood decimated all air-breathing land animals except two of each kind aboard Noah’s Ark. The Ark landed in the mountains of Ararat, which most Bible scholars think is somewhere in modern Turkey. But if this is true why aren’t there any marsupial moles in the Sahara Desert? Why aren’t there sugar gliders in the Amazon Rainforest? How did two-thirds of all marsupials end up in Australia?
Creation Research Can Help Us Develop a Model
Contrary to popular belief, young-earth creation scientists don’t only want to debunk unbiblical claims about Earth history. They also want to develop a well-rounded understanding of the history of the world God created, one that is biblically sound and explains more evidence than the conventional understanding. To do this, we can develop a scientific model.
This is why we need to understand why so many marsupials ended up in Australia and how they got there! The research needed to solve this mystery is quite young, but progress has been made. As of now, there exist two proposed models. But before we get to them there are some more things we need to know about marsupials.
How Many For Your Traveling Party?
It should be remembered that not every species of marsupial was required to migrate to Australia from the Ararat region. God told Noah to take at least two of each kind of air-breathing land animal aboard the Ark. After the Flood these animal kinds diversified into many different species.
This means that every species would not have needed to migrate to Australia. Some species likely came from one ancestral kind that had previously migrated to the Land Down Under sometime after the Flood through the means of diversification. For example, kangaroos, wallabies, wallaroos, tree kangaroos, and quokkas all probably descended from a common ancestor that survived the Flood.1
Which Fossils Are From the Flood?
Some creationists attribute the bulk of the fossil record to the Flood. They commonly assume that any marsupial fossils we find are of those buried by this grand catastrophe. This is problematic, however, since the fossil counterparts of modern marsupials are also endemic to Australia. Are we to expect that these marsupials migrated from Australia to Ararat, and then only back to Australia?
Recent research from the field of Flood geology might be helpful here. In their research of the Earth’s rock formations, young-earth geologists have identified several criteria in the fossil-containing rocks they can use to differentiate those formed during the Flood and those formed after the Flood.2 For example, since the Flood was global, we would expect to find widespread marine deposits on the continents. Fossils of modern marsupial types, however, do not appear in these rock layers. We find them only in fossil sites on top of the Flood’s marine deposits, such as those formed in lakes, or those carved into Flood or early post-Flood rocks, like caves and sinkholes. This indicates that these fossils belonged to animals that lived after the Flood.
Marsupials did not travel from Australia, to Ararat, and then back to Australia. As they do not appear to be present in the Flood’s fossil record, we do not know where they were living before the Flood. (For all we know, they may have been living in the area where Noah built the Ark!) What we do know is that they were on the Ark, which landed in the mountains of Ararat. From there, they migrated to Australia for the first time after the Flood.
Why Isn’t There a Fossil Trail of Marsupials from Ararat to Australia?
Likelihood of Fossilization
Many people think that we should find fossils of marsupials between Ararat and Australia if such a migration occurred. But they forget that the fossil record is not a perfect snapshot of all life forms alive at any given point in time. This is because when an organism dies, it usually does not become fossilized. Most departed organisms are consumed by scavengers or simply decay to nothing in the elements. Therefore, the likelihood of any one individual becoming fossilized is quite slim.
It is for this reason that the fossil record is biased toward organisms with high population counts. If only a small number of a type of organism are in existence, it is unlikely that they will ever be found as fossils. As such, an organism’s fossil distribution may not reflect its total distribution throughout history. So the fact that we do not find Australian marsupials anywhere but Australia does not prove that this was the only place they lived. What it does suggest, however, is that the Land Down Under was the only place where they truly came into their own.
The migration route marsupials used to get to Australia may be an example of a filter-bridge. A filter-bridge is a natural barrier that prevents some animals from passing through while allowing others.3 It is possible that marsupials had certain features or abilities that allowed them to migrate to Australia. Perhaps there was something that prevented placental mammals (those that don’t carry their young in pouches) from making that same journey.
Or, maybe, Australia’s isolation made it possible for marsupials to gain a foothold there, unlike other places. One important factor to marsupial domination appears to be isolation from most other mammals. Many do not appear capable of living alongside placental mammals. Some scientists think that competition with dogs played a role in the complete extinction of the thylacine (a meat-eating marsupial).4 They may also be responsible for the extinction of the Tasmanian devil on the Australian mainland.5 Even today, the introduction of placental mammals like foxes6 and rabbits7 have sadly put native marsupials at risk of extinction.
If most marsupials were unable to compete with placental mammals in regions outside of Australia, it is little wonder that they never attained a high enough population to warrant their appearance in the worldwide fossil record.
Two Models: Sundaland Route vs. Down Under Route
Creation researchers have developed two tentative models attempting to understand the modern distribution of marsupials. Let’s take a look at them.
The most popular model among young-earth creationists is what we will call the Sundaland Route.8 This model suggests that the ancestors of modern Australian marsupials migrated through southeast Asia until they came to the Sundaland region. This region connected many Southeast Asian islands to the mainland during the Ice Age, when sea levels were much lower. From there, they traveled on to Australia.
This model has the advantage of being the most straightforward explanation. The main unresolved issue with it, however, is that the land connection was incomplete. Wallacea, a series of islands and deep water channels, separates Sundaland and Australia. To everyone’s knowledge, these channels have never been above sea level. One possibility is that marsupials utilized natural rafts to get across the wide stretches of ocean. In recent times, researchers have observed that animals have spread to new places across seaways by these same means.9 The natural rafts used in these instances typically consist of floating log mats, plant debris, and other vegetation.10
Down Under Route
Proposed by Chad Arment in 2020,11 this model can be called the Down Under Route. It suggests that the marsupials utilized natural rafts across the Atlantic, made their way down through South America, “down under” through Antarctica, and finally up into Australia. Evidence that backs up this model suggests that animals could (and in fact did) move between the aforementioned continents. Fossils of the extinct, flightless terror birds are mostly known from South America. The same is true of the modern-day, weak-flying hoatzins. However, the fossil records of both birds show up in Africa and Europe as well.12,13 Though only known in Australia today, fossil platypus teeth have been found in South America,14 and the fossils of one type of marsupial, Chulpasia, are known from both continents.15
Arment points out that according to the Upper Mesozoic/Lower Cenozoic Flood model advocated by most young-earth paleontologists, Australia and South America did not completely split from Antarctica until sometime after the Flood. This would have allowed animals passage across these landmasses. In addition, the Atlantic Ocean would have been narrower, reducing the amount of time animals would have to spend adrift on a natural raft.
Young-earth creationists have developed two models that attempt to explain how almost all marsupials ended up in Australia. By combining the research efforts from three different fields (geology, paleontology, and biology) we can attempt to answer tough questions like these. There is still more work to do, but progress is always an encouraging sign that we are moving in the right direction.