Was that the biggest rat you ever saw? Was it about the size of a cat, with gray fur, beady eyes, and a long naked tail?
That was no rat. You saw a Virginia opossum. Philadelphia’s only marsupial gets a bad rap, but it is a peaceful, harmless neighbor.
The fact that they look like rats is a coincidence (Lots of mammals look like rats. The rat body plan as the default for mammals), but like a rat they have a long, naked tail and pointy snout. They have gray fur and grow about as big as a house cat. They are excellent climbers, using a long thumb-like toe on their hind paws and that long, prehensile tail to grip branches as they go.
Opossums live nearly everywhere in Philadelphia, from our neighborhoods into our wooded parks. If they have shelter and food, they’ll make it work.
Opossums will eat just about anything they can: fruit, bugs and other small animals, scavenged roadkill, trash, and pet food.
Opossums are mostly active at night, though you’ll sometimes spot one walking around in the morning. They tend to shuffle along at an easy pace and use their sharp sense of smell to locate food.
Although they can put on a good show when cornered, baring their long jaws full of sharp teeth, they are basically harmless and will do everything they can to get away from people. Opossums are famous for playing dead when threatened; basically they pass out from fright, which can be enough to make some predators lose interest.
They do not hibernate and are active year-round. In colder climates they can suffer from frostbite, losing the tips of their ears and tails.
Virginia opossums are our only marsupial. After only about 12 days of gestation they give birth to jelly-bean-sized babies that complete their development in a pouch, just like kangaroos or koalas. After about eight weeks they start venturing out of the pouch, and they’re ready to strike out on their own at about five months.
History with Humans
The Virginia opossum (“opossum” is a Virginia Algonquin word) have expanded their range since European colonization of North America. They have followed our agriculture, roads (which yield a bounty of roadkill to a scavenger like an opossum), and trash north into New England. Southerners who relocated to California in the early 20th Century also took opossums along to release and hunt for meat, thus expanding their range to the West Coast.
You can find opossums wandering around at night. An evening walk in the neighborhood might turn them up, as will a camera set up in your alley or breezeway. You will often find them as roadkill. Sadly these slow, clumsy critters aren’t great at crossing the street.
Opossums leave distinctive footprints with their thumb-like toes on the hind paws, Look for them on muddy patches of trails or in the snow.
Living With Opossums
Opossums are easy to get along with. They pose no threat to us or to our pets, but it is best to avoid feeding them, intentionally or unintentionally. This means keeping your trash securely contained and not leaving pet food outside (remember that when you feed stray cats, you also feed lots of animals you don’t want to feed, like rats, raccoons, skunks, and opossums).