The Natural History Of The Opossum
The opossum is an incredibly unique animal. It has remained relatively unchanged for 75 million years, and in fact is the oldest surviving mammal family from the age of the dinosaurs. There are over 60 different species of opossums, but only one of these species lives in North America - the Virginia Opossum.
The uniqueness of the opossum makes him a valuable member of our wildlife community. He has more teeth (50) than any other American land mammal, and puts them to good use eating cockroaches, moles, crickets, snails, rats, mice, overripe fruit, and dead animals of all types. He is more immune to many diseases (including rabies) than your neighbor's dog or cat, and even has a remarkable resistance to poisonous snake bites.
Opossum are nocturnal, with a keen sense of hearing and smell. They don't fear water and are good swimmers. They will take up residence practically anywhere, including stumps, haystacks, attics, garages (keep the doors closed!), road culverts, hollow trees, rock piles, and abandoned burrows of other animals. An adult opossum weighs anywhere from 4 - 15 pounds. He has a strong tail for help with climbing and balancing, and for scooping up leaves for nest building, but will rarely actually hang by his tail once he reaches adulthood.
Opossums are quiet, reclusive, solitary animals whenever possible. They are exceptionally non-aggressive, making a stand only when they feel like they can't run away from danger, or when they're protecting their babies.
A threatened opossum will try to look very ferocious by growling and showing off its 50 teeth. If that doesn't do the trick, he may drool and blow bubbles out his nose to make the attacker think he's sick and unappetizing. In very hazardous situations, his instincts will take over, slowing down his heart and breathing so that he appears dead, commonly called playing possum, hoping his attacker will lose interest and go away. Once the coast is clear, he will come out of his trance and amble off to resume his, solitary, unassuming lifestyle.
Opossums are marsupials, meaning they care for their undeveloped young within a pouch. They usually have one or two litters a year, the first in February or March. Opossum babies are born thirteen days after a successful mating, and are so small at birth that a litter could fit into a teaspoon!
The young stay in the pouch nursing for about two months. Once the babies have developed some fur and are close to opening their eyes, the mother will allow them out of the pouch to spend some time clinging to her back. As the babies grow older, their mother may temporarily leave them tucked safely in the den while she goes looking for food, returning home after a few hours of foraging so that her babies can crawl back in the pouch and nurse. Offspring may remain with the mother for almost a year.
It's A Possum Alright!
Rescue Or Leave Alone?
There are generally three situations that cause a baby opossum to be separated from his mother: either the mother is killed (by man, dogs or a natural predator), the baby falls off the mother as she is fleeing from danger, or the mother is prevented from returning to her nest.
Rescuing babies still clinging to their dead mother is a very satisfying act of compassion, especially when the mother was killed by a car because someone couldn't bother to slow down to give her time to cross the road. Opossums hit by a car can have live babies in the pouch, babies still clinging to her back, or babies wandering lost and confused up to 50 feet away from their dead mother. If there are babies anywhere near, they need to be rescued, or they will die a slow death from hypothermia (loss of body heat), starvation, or become the temporary, soon-to-be dead play toy for the neighborhood cat or dog.
Babies that have fallen off the mother as she was fleeing from danger will sometimes be reunited if the mother feels secure enough in her own safety to return to the area. Baby opossum have a very distinctive call they make when they're in distress, kind of a shoo, shoo sneezing sound. Often the mother will return to retrieve her wayward child if you give her a chance. Watch the baby from a distance, in part to protect it from cats and dogs that may also hear the crying, but mainly to see if the mother will return. If she doesn't show up within a couple of hours, you may need to rescue.
Opossums will occasionally leave their young in the den to go out and forage for food. If that den happens to be in your garage or under your tool shed, you may inadvertently doom the babies by closing off their mother's access to them. Or you may frighten her as she's returning to the den, causing her to run off and abandon her babies.
The humane solution is to simply make the area uninviting. Keep the area well lit 24 hours a day, remove any food sources (pet food, overripe fruit on the ground), leave a radio turned on low, scatter a few moth balls around the general area (not too close to the babies!). Remember, you don't want to frighten the mother, you just want to encourage her to find a new home.
Once the mother realizes the neighborhood has deteriorated, she will move her babies to a new den. It may take her 3 - 4 days to get everyone resettled, so give her time. When you're certain all the babies are out of the den, close up the access routes so that the next opossum wandering through doesn't take up residence.
Injured adult opossums require special handling. They are very strong, very fast (you'd be surprised), and have very powerful jaws with a lot of sharp teeth. In spite of all this, an experienced wildlife rehabilitator will gladly spend the time and energy necessary to help an injured opossum be released back into the wild. Opossums are very resilient animals, so if you find an adult lying immobile, whether it's in your yard or on the side of the road, his injuries are probably severe enough that he needs to be rescued. Opossums trapped in garbage cans or trash dumpsters also sometimes need some rehabilitation time, since they can be dehydrated from not having water for a few days, or can have open wounds that may require a few stitches.
Did You Know?
Also known as: Opossum, possum
What is the scientific name? Didelphis virginiana
Pronounced di-DELL-fis vir-gin-ee-AAN-a
What does it mean? "Virginia two-womb." Didelphis is from two Greek words, di meaning two or double and delphys meaning womb. This refers to the opossum's fur-lined pouch (marsupium) which acts as a secondary womb. Virginiana is the Latinized form of the state of Virginia, source of the first scientifically described opossum.
Where are they located? How many subspecies are there?
Opossums are found throughout most of North America, from southern Canada to Mexico. While originally restricted to the eastern United States, they have continued to expand their range both west and north (Gardner, 1982). There are four subspecies of opossum, but only one that occurs over most of the United States: D.v. virginiana (Gardner 1982; McManus 1974).
Where do they live?
The opossum prefers deciduous woodlands near water, but can be found in a variety of habitats including marshlands, forests, farmland, and residential areas (Gardner 1982).
What do they look like?
Opossums are gray with long pointed noses and hairless ears and tail. The tail is "prehensile," which means it can be wrapped and folded around objects like a tree branch. While certain monkeys have prehensile tails and use them to hang from, opossums don't normally hang by their tails (Nowak 1991).
How big are they?
The head and body length is between 13 and 20 inches; tail length is between 10 and 21 inches (Maser et al 1981). Males can grow up to a total length of 37 inches; females to a total length of 36 inches (Hall 1981). Males can weigh between 1 and 13 pounds, but average around 5 pounds. Females weigh between one-half and 8 pounds, but average about 2 pounds (Gardner 1982).
How long do they live?
The average life expectancy is one and one-third years (Petrides 1949), but even this is thought to be a high estimate (Gardner 1982). The oldest recorded opossum in the wild was about three years old (Gardner 1982). In captivity they can live between four and five years (Gardner 1982).
What do they eat?
Mostly insects and carrion (McManus 1974), but the opossum is omnivorous, eating a variety of animal and plant matter. The diet includes: grasshoppers, slugs, caterpillars, mice, frogs, shrews, snakes, bird eggs, corn, chestnuts, acorns, blackberries, wild cherries, persimmons, grass, and carrion from such mammals as deer and rabbits (Gardner 1982).
Owing to their unique marsupium, the birth of opossums is particularly fascinating. Female opossums can have up to two litters per year with sizes ranging from one to 17 newborns per litter. The young are born in an embryonic stage 12 or 13 days after conception and are only about one-half inch long and one-tenth of an inch wide. You could fit an entire litter into a teaspoon. After emerging from the uterus, the newborns have to climb one to two inches from their mother's vulva to the pouch where they attach themselves to one of 13 nipples. Not all newborns will reach a nipple and not all nipples will be functional if they arrive. Sometimes only seven to ten of the 13 nipples will produce milk. Those newborns that can't find a functional nipple perish. After attaching, the tiny opossums will stay attached and nurse for 50 to 65 days. They are weaned after 95 to 105 days (Gardner 1982; McManus 1974; Asdell 1964).
Opossums are probably best known for playing dead, a defense mechanism that is utilized to keep them from being eaten and is only used as a last resort. Opossums don't move very swiftly, their fastest speed was clocked at a roaring 4½ miles per hour (McManus 1970). Instead, they have developed another way to escape predators called "death feigning" (pretending to die). This unusual habit of defense is successful because predators don't often attack or eat dead animals and they don't always eat their prey as soon as they have captured it. "Playing possum" has also been observed in ducks, rodents, reptiles, and amphibians (McFarland 1982).
While pretending to be dead the opossum lies on its side, opens it mouth slightly, draws the corners of its mouth back, and begins to drool. The eyes remain open. If the predator goes away the opossum may recover immediately or it may take up to 20 minutes to start moving again. Even though they are "feigning death" and don't react to being probed, opossums "playing possum" are still aware of what is going on around them. In fact, experiments have shown that certain body measurements like heart rate and brain waves are no different between an awake opossum and one "feigning death" (Franq 1969). Opossums can feign death for a period of several minutes up to six hours (McManus 1970).
Roast 'possum with Kraut
1 Dressed Opossum; trussed
Just Game Recipes: http://www.justgamerecipes.com/
The Opossum - ... For another web site about the opossum please visit Possum Rescue. It is maintained http://www.wildlifecare.com/possumbio.html
Oppossum - Virginia Opossum. Also known as Opossum, possum What is the scientific name? Didelphis http://www.sou.edu/library/jim/wildlife/opposum.htm
Web Master http://wildlifecare.com
'Possum Network - America's marsupial, the Virginia Opossum. A thoughtful and fun place that kids and parents can browse together. National Opossum Society - welcomes you to the world of the Virginia Opossum
Opossum Society of the United States - nonprofit wildlife rehabilitation and educational organization dedicated to providing care for injured and orphaned wild opossums.