Opossums get a lot of hate. We get it; these critters make Norwegian rats look like beauty-pageant winners. That said, this humble and homely little mammal is actually far more interesting than you'd think. Here are five things you probably didn't know about the 'possum.
1. The Living Fossil The opossum is the Earth's oldest surviving mammal. It's nicknamed the “living fossil,” and for good reason: This animal has survived virtually unchanged since the Cretaceous/Paleogene extinction event 65 million years ago, which marked the end of the dinosaurs.
2. Monkey's Uncle 'Possums have opposable thumbs; they even have “thumbs” on their hind feet. They're the only non-primates in the world to have this bonus, and they use them to full advantage. You see, possums are remarkably intelligent (especially given their teeny-tiny brains, which are one-fifth the size of a raccoon's), so they actually use those thumbs to open latches, containers and fasteners. (This is what makes them so efficient at getting into your garbage cans.) What's more, the opossum's tail is prehensile, which means the tail can wrap around branches and vines to help the animal climb.
3. Smile Pretty The opossum has 50 teeth, which is more than any other mammal in North America. (Adult human beings, by contrast, make do with 32.) If threatened, the opossum will bare all of those teeth in a growling, hissing threat display. However, as you might already know, that's not the possum's primary threat-management strategy...
4.Playing Possum You've probably heard the term "fight or flight" bandied about when referring to a living creature's reaction to danger. But those aren't the only options: A third one would be "freeze," and the possum is a master of it. “Playing possum” has joined the lexicon as a metaphor for playing dead, but it's even more impressive in practice than you'd think. It happens when an opossum is confronted with danger that it can't escape, and seems to be completely involuntary. The animal flops onto its side, eyes open and tongue hanging out, while its heart and respiration slow to a crawl. This dazzling display of deadness is embellished when the possum emits a green, putrescent fluid...from exactly the place you'd expect a green, putrescent fluid to emerge. It's enough to turn even the most iron of stomachs (including ours). Interestingly, the animal never loses consciousness during this phase. Usually, the possum will regain the use of its body when the threat withdraws, but the "playing possum" state can last as long as six hours.
5. Tick Magnet Like all mammals, opossums are frequently targeted by ticks. Unlike many mammals, however, possums are actually very clean animals, and groom themselves as often and thoroughly as cats. When ticks attach to possums, they're promptly groomed away and eaten (possums are omnivorous, and insects are a normal part of their diets). It's estimated that a single possum might "vacuum" up as many as 5,000 ticks a season...which serves to limit the spread of tick-borne diseases such as Lyme Disease and Rocky Mountain Spotted Fever. Additionally, opossums' immune systems are incredibly resistant to disease, particularly rabies. They're eight times less likely to carry rabies than other mammals.
We doubt any of the above will stop you from wrinkling your nose and saying "yuck" when you see an opossum digging through your trash...but it may help you feel a little better about having them in your yard.