Virginia opossums: The American marsupials that have barely changed since the time of the dinosaurs

By Lydia Smith published July 26, 2025

Virginia opossums are the only marsupial species in North America.



Virginia Opossum in the snow.

The earliest known relatives of opossums appeared over 65 million years ago. (Image credit: Leonid Korchenko/Getty Images)


With their beady eyes, big ears, hairless tails and short, stocky legs, opossums are distinctive marsupials. Despite their odd appearance, these animals have a rich evolutionary history and have remained largely unchanged for millions of years. Their remarkable ability to adapt to different environments, food sources and predators has helped them survive from the time of the dinosaurs to today.

The Virginia opossum is the only opossum species found in the United States and Canada. Opossums have the smallest brain-to-weight ratio of any North American mammal.

The earliest known relatives of modern opossums lived over 65 million years ago, around the time dinosaurs went extinct. A 2009 study published in PLOS ONE found that peradectids, a family of marsupials known from fossils mostly in North America and Eurasia, are the closest extinct relatives of living opossums. Like modern opossums, peradectids had opposable thumbs on their hind feet and a similarly shaped skull — features that have remained nearly unchanged for millions of years. The earliest opossum fossils date back to the early Miocene epoch, roughly 20 million years ago.

One key reason why opossums have survived for so long with few changes is because they are adaptable. These marsupials eat almost anything, including fruit, insects, small animals and animal carcasses. They can live anywhere from forests to urban backyards. And, although they are mostly nocturnal, they can sometimes be seen in daylight if food is scarce.

More:
https://www.livescience.com/animals/land-mammals/virginia-opossums-the-american-marsupials-that-have-barely-changed-since-the-time-of-the-dinosaurs