Evolution and Facts About Marsupials in North America

Marsupials. When we hear the word, our minds tend to go to Australia first. They have the most famous marsupials living there, but they don’t have the only marsupials. In the Americas, we have our share of marsupials, too, such as the opossum. In fact, new discoveries in the field of paleontology suggest that marsupials as a whole may have American origins. Some posit that the marsupial clade originated in South America and then spread to parts of North America and Australia and New Zealand. However, a recent discovery shows that there was a marsupial species living in North America before the date marsupials are first recorded in South America. That species was Didelphodon vorax. Not only was this creature a marsupial, but it was a fierce predator who had the strongest bite, pound-for-pound, of any mammal ever recorded. This creature was badger-sized and preyed on anything from small animals such as snails, to even some dinosaurs. It is thought that they also could have been scavengers.

The discovery of Didelphodon has yielded many insights into the ecology of the world around the creature, 85 to 100 million years ago. The fossils also point to five lineages of marsupialia originating in North America. From here, they migrated into South America and Australia, where they become larger and began to consume a wider variety of foods. During the Great Extinction, in which dinosaurs were killed, and the mammals and birds diversified to fill the ecological niches left empty by the dinosaurs, most marsupials in the Americas also were killed, though not all of them. Unlike in Australia, where marsupials become the type of animals to fill most of the niches, other mammals rose to fill those in the Americas, though there still were many types of marsupials left.

What caused such widespread diversity in Marsupialia to die out, and fairly recently, too? Just 13 million years ago marked the end of the reign of the marsupials. Even in Australia, large marsupials went extinct. There are a few theories for this. Firstly, early humans could be to blame. Either they damaged to environment to such a degree that it no longer could sustain so many species, or they were hunted to extinction. This theory is so similar to our situation today that, if this were to be true, it should serve as a wake-up call to do a full-stop and pour resources into conservation. If our ancestors who numbered only a fraction of our current world population and lived in small hunter-gatherer groups could effect the end of so many creatures, we are doing more damage than that right now. Another theory, no less dire, suggests that global warming, then a natural process, led to the demise of the world’s megafauna, including many marsupials. The process of climate change has been sped up by human behavior, which will only worsen the destruction it causes.

Some ways to curb these consequences are to be careful about your energy consumption, and use sustainable sources of energy, such as solar power, whenever possible. Another way is to use re-usable items such as tote bags and water bottles, which will reduce how much non-biodegradable materials we put in landfills every year.

Stay tuned for our next blog post. We share two every week! Until then, goodbye.

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