Why is the American opossum apperently the most relatively ugly? Some are downright cute! But the aquatic one and the ones in Australia are so much prettier and skinnier! Why ours so funky?
fun fact, marsupials actually originated in South America, which used to be connected to Australia via Antarctica.
marsupials colonized both antarctica and australia, but about 30 million years ago the three continents broke up and went their separate ways, ending up where they are today.
obviously things didn’t end well for the antarctic marsupials, who died out, but australian marsupials pretty much had it made! they were the first mammals to colonize the continent and they didn’t face competition from placental mammals until much much later, in the modern era.
south american marsupials, however.
when south america eventually drifted north to slam into north america like a wayward bowling ball, the Great American Biotic Interchange happened! which is a fancy way of saying that animals who had before been limited to a single continent now had the run of the whole western hemisphere, and entire species rampaged back and forth over the new central american land bridge for millions of years in an intercontinental evolutionary war.
and unfortunately, it was a war the south american marsupials lost. they were outrun, outgunned, and just all-around outcompeted by the north american placental mammals, who took their place in the south american ecosystems as things finally began to settle down.
in the confusion, opossums had managed to move north and establish a foothold for themselves in north america, making them the sole marsupial survivors of the Great American Biotic Interchange war. today, they can be found across all of the americas!
they’ve been out of contact with the rest of opossum-dom for well over 30 million years, and that’s why they look so different from the modern australian possums. show some respect to these tenacious survivors!
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