With the temperature moderating in New Hampshire, many people are noticing opossums re-appearing in their neighborhoods.
Something Wild co-host Grace McCulloch, of New Hampshire Audubon, reports that during the backyard winter bird survey in February, there were a number of opossum sightings as well.
“I looked out the window on my front porch last week, and there was an opossum, in the middle of the day,” says Dave Anderson, Something Wild co-host. “I guess it was there for the bird feeders.”
Although they aren’t particularly well-adapted for New Hampshire winters, suffering from frostbite on their hairless ears and tails, they are present throughout the state, and plentiful enough to have been named the official state marsupial. They are the only native marsupial in the U.S.
Although we commonly call them "possums," the opossum that roams North America is technically the Virginia opossum (Didelphis virginiana). A possum is actually a little brown marsupial found in Australia.
Opossums are ancient creatures that shared the land with the dinosaurs that roamed the earth over 70 million years ago.
It has been possible to observe the relatively rapid northward expansion of opossums in New Hampshire in real time. The earliest sightings were along railroad rights of way in the 1980s. They are now common and have been observed north of the White Mountains.
Like raccoons and skunks, opossums have learned to capitalize on food sources that people provide around their homes: bird feeders, trash and pet food bowls left outside.
Opossums typically have their babies beginning in February. They're basically born as embryos the size of a bumblebee, and must latch on to one of the mother's 13 nipples to survive for another eight weeks. Like their kangaroo cousins, opossum juveniles are called "joeys."
They stay in the mother's pouch for 8-10 weeks before they are able to ride around on her back. They cling so tightly to their mother's fur that it's almost impossible to remove them without harm.
They have opposable thumbs on their feet to help them climb trees and grab branches. These clawless, thumb-like digits (known as the hallux) provide a strong grip that complements their prehensile tails.
Thus they are able to climb trees and balance, even encumbered with as many as a dozen babies on their back.
They have a low body temperature and a strong immune response that allows them to resist many diseases, including rabies and Lyme disease. They can eat a bat killed by rabies, essentially preventing the disease from spreading.
They are known for eating ticks and can tangle with venomous snakes as well as consuming roadkill. Studies are being done on the proteins in opossum blood to see if a rabies or snake venom antidote for humans could be developed.
However, they can pass on salmonella, as well as fleas, but they do groom themselves in much the same way that cats do.
Despite excellent night vision, opossums are nearsighted and rely heavily on scent and touch to navigate.
Their smooth brains are proportionately smaller than most mammals, but their memory is excellent, especially when it comes to where food is commonly found. In one study, opossums scored better than dogs for learning and have also outperformed rats for solving mazes.
Note: if you see a dead opossum on the road, pull over and check it out. The babies can survive for days in the pouch. Call a licensed wildlife rehabilitator for help.
Something Wild is a partnership between NH Audubon, the Forest Society and NHPR.
