Wild Profile: Meet the opossum

Female opossum with babies on her back By Evelyn D. Harrison/Shutterstock

The opossum is one of a kind—at least in that it’s Canada’s only marsupial. Cat-sized, but heavier and with shorter legs, opossums have paper-thin ears and a rat-like prehensile tail. Though opossums are more common in the southern U.S., they’ve been steadily moving north for years. Like raccoons, they’re well-adapted to urban environments. They eat almost anything, including, happily, a lot of pest critters: cockroaches, rats, mice, and, perhaps best of all, ticks.

Yup, opossums, research has discovered, are a quiet potential weapon against Lyme disease, thanks to their voracious appetite for the ticks that feed on them. Though there’s no hard data showing what kind of impact opossums have on Lyme-carrying ticks, and the spread of the disease, they sure as heck can’t hurt. One opossum, in theory, can eat as many as 4,000 ticks in one week! Thanks for that, guys!

New research is helping us understand Lyme disease better.

Opossums begin life tiny and undeveloped. A female’s gestation period is a mere 13 days, after all. She can deliver up to 20 young, with each baby weighing less than a gram. The entire litter is small enough to fit into a teaspoon; after a few days, the babies are about the size of a dime. Baby opossums spend the first two months of life in Mom’s pouch, where they can nurse.

Opossum reproduction was mysterious and misunderstood for a long time. Scientists used to believe that females gave birth by sneezing the embryos out of their noses and into their pouches. Uh, sure. That’s…logical. Truth: the babies travel from the birth canal into the pouch, and stay there until they’re large enough to climb onto her back. By about five months, they’re weaned and old enough to be independent.

Do opossums really “play possum”? Yes—they’ll feign death if cornered, even in the middle of the road. So always brake or swerve for possums. We need them.

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