<<

By Christine Petersen ▼ oung Y naturalists This relative of has made itself at home in Awesome Minnesota.

In 1607 a small group of Englishmen landed three ships on the banks of the Jamestown River in a place that later became part of the state of . They hoped to settle there and build the first English colony, or village, in . While in the forest, Captain John Smith found an odd with grizzled, gray and a bare, scaly . Its long, white face ended in a shiny, pink nose. To Smith, this creature looked like a patchwork of a , a rat, and a pig. Then he noticed something even more unusual—a hidden in the skin of the animal’s belly. Within this fur-lined pocket, a litter of baby opossums was curled up, warm and safe. Captain Smith had traveled across Europe and Africa, but he had never encountered any creature like this. He asked the local Powhatan Indians what they called it. Apasam, they replied. It meant “white animal.” Sounding out the word, Smith wrote it in his journal—opassum.

BILL MARCHEL The word later changed to .

46 Minnesota Conservation Volunteer January–February 2014 47 Parents With Pouches The ( virgin- mother has a pouch where their new- iana) is a . have borns stay and nurse until fully formed. How ? and produce milk to feed their young. The Virginia opossum is North Amer- The opossum is a slow-moving crea- Most baby mammals develop inside the ica’s only . and ture with a reputation for not being mother’s body and are born fully formed. have a total of about 75 very smart. For example, when faced Opossums are . They deliver (kinds) of marsupials. Kangaroos with a car’s flashing headlights or tiny babies whose heart, brain, and other and , marsupial relatives of opos- honking horn, an opossum in the organs are still growing. The marsupial sums, live in . road does not run. The danger does MARY CLAY, DEMBINSKY PHOTO ASSOCIATES DEMBINSKY PHOTO MARY CLAY, © After they leave the pouch, young opossums often hitch a ride not seem to alarmSmart the opossum. on their mother, clutching onto her fur. Sometimes a person can walk right Pouch Babies up to an opossum without scaring it Opossums in Minnesota mate between True Grip away. Because of the opossum’s slow January and May. A female opossum Have you heard that opossums hang by their ? reaction to possible danger, some often bears two litters of six to 20 babies Actually, they rarely do this. The opossum uses its people think opossums are “stupid.” each . A full-grown opossum is about long prehensile (able to grasp) tail for balance and to But this species has survived for the size of a house cat. A newborn opos- grip as it climbs trees. eons and even expanded its range. sum is only half an inch long and weighs See the way your separates from the other How smart is the opossum? far less than a penny. It would take around four fingers? That arrangement allows you to wrap Well, the opossum does have an ED KANZE, DEMBINSKY PHOTO ASSOCIATES ED KANZE, DEMBINSKY PHOTO © 16 of them to weigh as much as a penny. Opossum newborns move into their mother’s warm, your hand around all kinds of things. The opossum unusually small brain. Scientists say Born blind and hairless, the baby opos- fur-lined pouch for their first few weeks of life. has a similar opposable digit on each hind foot, per- it has a small encephalization quotient, sum has a strong instinct to survive. It fect for clutching tree branches. All four feet have meaning its brain is much smaller can feel the pull of gravity and uses its along as she searches for food. They prac- and pads with tiny ridges. Just as cleats prevent than expected based on its body tiny front claws to climb up its mother’s tice survival skills, such as how to climb a soccer player from skidding on a grassy field, the size. And the opossum is missing a belly and into her pouch. There it finds a trees and stay away from predators. opossum’s textured feet keep it steady while climbing. connection between the left side , also called a teat, which provides Young opossums also learn the impor- and the right side of its brain. Like mother’s milk. Each baby latches onto tance of cleanliness. Wetting their front other marsupials, the opossum lacks one and won’t let go for many weeks. paws with saliva, joeys bathe from top to Rarely Sick a corpus collosum, a band of nerve fi- Like kangaroos, young opossums are bottom every day. Their long claws make Opossums rarely become ill with rabies and other bers that runs between the left and sometimes called joeys. After about 70 good combs to remove tangles, bits of wildlife diseases that can pass to people or pets. right brain hemispheres. days, opossum joeys begin to explore, food, and insect pests. Perhaps that is because the opossum’s normal Opossums are nice critters that climbing in and out of the pouch. After When they are 4 months old, opos- body temperature is several degrees lower than are just slow to process incoming another month, the mouse-size joeys sums leave their mother and face the that of other mammals. Most viruses need warm- information. crawl onto their mother’s back and ride world alone. er conditions to survive. —DNR furbearer biologist John Erb

48 Minnesota Conservation Volunteer January–February 2014 49 here and munches grasses there. A good vegetables. But opossums rarely take swimmer, it might dip into a stream to enough to do harm. In some cases, they catch a . With its 50 sharp teeth— are actually helpful. Opossums eat in- the most found in any North Ameri- sect larvae and slugs, including some can mammal—the opossum crunches that could damage farm and garden through shells and munches small animal plants. They dine on rotting fruits, vege- bones. It climbs trees to pick nuts and fruit. tables, and dead , called carrion. People may think of opossums as In this way, opossums serve as part of pests when they eat fresh fruits and nature’s cleanup and recycling crew. Dangerous Dinner The shy opossum can be a daring hunter. opossums built up defenses against snake- It sometimes eats a poisonous snake, such bites. One defense is a substance in the as the timber found in south- opossum’s blood. Molecules of this sub- eastern Minnesota’s rocky prairie habitat. stance can attach to and destroy snake ALLEN BLAKE SHELDON How does it do this without being killed venom as it moves through the opossum’s A hollow tree can be a shelter for an opossum, but not for long: It keeps moving and finding new homes. by the snake’s poisonous venom? body. Researchers are looking for ways to Opossums have hunted venomous make a similar substance to treat people Home for a Day snakes for millions of . Over time, who get bitten by poisonous snakes. The opossum takes a relaxed approach to housing is the time it spends to make a making a home. One day it might find an simple grass bed. Carrying one load of abandoned squirrel nest or a cozy space grass in its tail and another in its mouth, within a rock pile or a woodpile. The next the opossum brings the bundles to a day it might settle in a hollow tree or squeeze favorite den to soften its nest. through a window to snooze in an old shed. But even a female with joeys rarely Because the opossum doesn’t dig or build stays in one place for long. One research- shelters, it almost never damages buildings. er found that opossums in her study area The opossum’s biggest investment in traveled 15 miles in just two weeks. What’s for Dinner? The opossum is nocturnal. After resting ing, smell, and taste. And it likes the taste all day, the opossum goes out at night of almost everything. It is an .

to feed. Although it doesn’t see well, the Waddling and wandering through the BILL MARCHEL opossum has exceptional senses of hear- night, the opossum digs up earthworms Minnesota’s winters are getting warmer, which might be helping the opossum move north in the state.

50 Minnesota Conservation Volunteer January–February 2014 51 An opossum mother’s fur is cozy for her babies, or joeys, but it is not made for really cold winters. New Neighbors When John Smith met his first opossum have followed these roads west and north, 400 years ago, this species did not live in enjoying free food from farm fields, gar- our part of the country. Its range reached bage cans, roadsides, and pet bowls. from the southeastern corner of North Historically, opossums lived in riverside America down into Central America. forests. Now they are just as likely to show Today, Virginia opossums live almost up in the city. Cities not only offer food, but everywhere east of the Rocky Mountains. they are also warmer in winter than forests MARY CLAY, DEMBINSKY PHOTO ASSOCIATES DEMBINSKY PHOTO MARY CLAY, Unless you live in the far north, opos- are. Sidewalks, streets, and rooftops reflect © sums are probably your neighbors too. sunlight, increasing the air temperature.

GIJSBERT VAN FRANKENHUYZEN, DEMBINSKY PHOTO ASSOCIATES FRANKENHUYZEN, DEMBINSKY PHOTO VAN GIJSBERT Opossums arrived in southeastern Climate change might also play a role © The opossum sometimes becomes frightened and appears to be dead—a tactic that can save its life. Minnesota sometime around 1900, but in the northward movement of Virgin- they aren’t really equipped to survive cold ia opossums. Climate change can be a winters. They and their ancestors evolved natural process, such as when the Earth Playing Possum for Predators in southern climates with warmer sea- warmed after the last ice age. For the past Opossums face many dangers. Traveling Playing possum is no joke. The fright- sons. This shows in their bodies and their century, people have been burning oil, at night on roads, an opossum might get ened opossum does not choose to play habits. Their fur coat doesn’t always keep coal, and gas to heat buildings, create elec- hit by a car. An opossum might fall prey to possum, or pretend to be dead. It collapses them warm. Their large, thin ears and al- tricity, and run cars and trucks. Burning a great horned owl. Coyotes and foxes are because it is extremely scared and suffers a most hairless tail make opossums vulner- these fuels also warms the Earth. other predators that eat opossums. temporary nervous shock. Its tongue lolls able to frostbite and stress when temper- In Minnesota the average annual tem- Whenever possible, the opossum’s first out of its mouth, and its eyes stare. It drools atures dip below freezing. They do not perature has increased about 1.5 degrees choice is to run away from dogs, people, and poops. Even if the predator bites, the hibernate—going into a sleeplike state since the early 1980s. The opossum needs and other threats. Unfortunately, it cannot opossum won’t move. Its yucky body flu- throughout the winter. Nor do opossums only small temperature increases to sur- run fast. If it is cornered, the opossum will ids and lack of movement usually cause stockpile food or build up a thick layer of vive in winter. For example, it might stay growl, hiss, and open its mouth to show its predators to lose interest and go away. fat to insulate and fuel them when fresh in its den for several days if the tempera- sharp teeth. But if this warning doesn’t scare After a few minutes or a few hours, food is buried under piles of snow. ture is below 21. But if the temperature away the possible predator, the opossum when the danger has passed, the opossum What brings this warm-weather animal rises to 28, it can keep active all night. collapses. This is called playing possum. gets up and continues on its way. into northern climates? Wildlife biologists With warmer winter temperatures, have a few ideas. Over the past century, opossums have settled in Minnesota. Teachers resources: farms and towns have grown up along These new neighbors add a little more Teachers guide: www.mndnr.gov/young_naturalists highways and rivers. Opossums might wildness to our world. nV

52 Minnesota Conservation Volunteer January–February 2014 53