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Raising Orphaned Opossums

RAISING ORPHANED OPOSSUMS
(Virginianus carolinensis)

By Mary Stockard
(Revised 2005)

Initial Stabilization Care for Baby Mammals

1. Check for injuries. Seriously injured babies should be taken to a veterinarian that day.

2. Warm the baby quickly if it feels cold. Methods for warming include:

1. Quick method: Place the baby wrapped in a wash cloth inside a plastic Zip-loc bag. DON’T seal the bag. Dip the bag in a bowl of warm (not hot) water. Gently swirl it around for about 5 minutes. This is not recommended for older, active young.

2. Heating pad: Set temperature on low. Place the heating pad half under a closed box the baby has been placed inside of along with ravel-free cloths to snuggle with.

3. Disposable plastic bottle: Use a plastic soft drink bottle or other plastic bottle. Fill it with hot water. Wrap it with a towel or other cloth. Place it inside a box with the baby. Make sure that it will not roll around possibly hurting the baby.

4. Rice sock: Fill a sock 2/3 full of rice. Microwave it on high for 2 to 2 ½ minutes. Place it in the bedding in the box with the baby.

3. Treat dehydration. Give fluids by mouth using a 1 cc syringe, eye-dropper, or pet nurser. Offer the fluids at room temperature hourly for up to 6 hours. Do not exceed 12 hours. Any of the following fluids may be used and can be purchased at the grocery or drug store :

· Gatorade ( regular or clear flavors)

· Pedialyte (clear)

· Sugar/salt water: 3 teaspoons Sugar, 1 teaspoon salt dissolved in 1 quart very warm water. Cool the water to room temperature before offering it to the baby.

4. Give it a warm box or pet carrier. Eyes closed infants and eyes open young that are in shock should be placed in a cardboard box or small/medium pet carrier with ravel-free bedding such as a few tee-shirts. Provide consistent source of warmth such as a heating pad on a low temperature setting. Place it half under the box or pet carrier.

5. Begin offering dilute formula. Make the formula as indicated in the diet section. Offer diluted formula every 2 hours using a 1 cc syringe, eye-dropper, or pet nurser. Syringes are better because there is less chance of aspiration. Give three feedings of 1 part formula / 2 parts water, then three feedings of 1 part formula/ 1 part water. If the baby does not develop diarrhea or bloat offer full strength formula at the recommended amounts and frequency for the age. If problems develop contact a veterinarian or the Alabama Wildlife Rehabilitation Center.

6. Provide food and housing as described in the age and development chart. Contact the Alabama Wildlife Rehabilitation Center if there are questions about the care instructions provided.


Opossum Diet Chart

Note: Volunteers who do not have access to Zoologic supplements can use the Home Formula.


Wildlife Center Formula:

1 part Esbilac powder

1 part Zoologic Milk Matrix 30-55

2 parts Water


Home Formula:

1 part Esbilac powder

1/3 part Heavy Whipping Cream,

1.5 parts Water


Formula Introduction:

Formula Break-In Chart

Always begin new infants on dilute formula, and work up to full strength formula gradually.

Feedings #1, 2 = 1 part full strength formula + 2 parts water every 2 hours for 4 hours.

Feedings #3, 4 = 1 part full strength formula + 1 part water every 2 hours for 4 hours.

Feedings #5, 6 = 2 parts full strength formula + 1 part water every 2 hours for 4 hours.

If at any time the infant develops diarrhea or bloating, cut back on the concentration of formula until the situation clears up. If such problems persist for more than 36 hours, seek medical advice.

How to feed: Use a 1 cc syringe to feed formula. Wrap the baby in a cloth to keep it warm and secure. And hold it in a sitting-up position. Opossums rarely suckle a syringe but will lick from it. As soon as the babies are used to the formula, you may pour some in a shallow dish. Opossums learn to lap from a dish quickly. However, any baby not drinking well from the dish should continue to be hand fed until it is lapping from the dish and gaining weight.

Stimulating urine and feces: This should be done for babies whose eyes are closed or just opening. Use a slightly damp cotton ball or tissue to gently stroke the genital area. The baby should produce urine within a few seconds. Babies may not urinate or produce feces every time.

Self-feeding diet: Once the opossums teeth have fully emerged begin offering the self-feeding diet. The base chow (Science Diet) should be soaked in water to make it soft and easier to eat until they reach about 12 weeks of age when it can be offered dry. Formula should be poured over the soaked chow until the babies have been weaned from formula at 10 weeks of age.

Two shallow dishes of water should be offered. One dish for drinking and one for defecating.

90% of diet: Purina puppy chow or Canine growth Science Diet (soaked in water until the opossums are older). (Pour formula over it until babies are weaned)

5% of diet: Fruits and vegetables cut in dime to nickel size pieces. Any fruit or vegetable may be used.

5% of diet: Insects such as crickets and worms, dead mice (cut up at first then left whole as babies get closer to release age).

Supplements: Lightly sprinkle the food with a calcium/phosphate powder to help prevent calcium deficiencies after the baby is no longer receiving formula.

Natural foods: Add as many natural food items to the self-feeding diet as are available.

Releasing hand-raised opossums

Opossums should be ready for release at 20 to 22 weeks of age. Prior to release, your opossums should have been in a large outdoor cage for at least two weeks, preferably longer. They should be acclimated to weather changes, outdoor noises and the sights and sounds of the world. They should be properly shy of dogs, cats and humans (EVEN YOU). They must be familiar with their natural foods.

The release site should be outside the metropolitan area, on land with appropriate shelter, a constant water source and abundant natural food resources. There should be other opossums in the release area but it should not be overcrowded with them.

Since opossums are nocturnal (active by night), it is best to release them in the late afternoon to early evening. Release when good weather is forecast for at least 4-5 days and the last chance of freezing temperatures has passed. Ideally, their nestbox should be left at the release site, under some bushes, and back-up food provided for 4-5 days until they have located their natural food sources.

REFERENCES

1. Fowler, Murray E. Zoo and Wild Animal Medicine, 2nd Edition. W.B. Saunders Co., Philadelphia, PA. 1986.

2. Harrison, Kit and George. America's Favorite Backyard Wildlife. Simon and Schuster, Inc. New York. 1985.

3. Martin, Alexander C., Zim, Herbert, Nelson, Arnold L. American Wildlife and Plants: A Guide to Wildlife Food Habits. Dover Publications, Inc. New York. 1951.

4. Marcum, Debbie. Substitute Milk Formulas for Opossum. Wildwood Farm 14206 FM2769. Leander, Tx. 78641-9109. 1988.

5. Marcum, Debbie. Stages of Development in Pouch Young of the Virginia Opossum. Wildwood Farm 14206 FM2769. Leander, Tx. 78641-9109. 1983.

6. Whitaker, John O. Jr. The Audubon Society Field Guide to North American Mammals. Alfred A. Knopf Publishing. NY. 1980.

7. White, Jan. Basic Wildlife Rehabilitation. International Wildlife Rehabilitation Council. Walnut Creek, CA 1988


Keeping Babies Wild So They Can Go Back To The Wild

A great many baby opossums are orphaned every year. As babies, they are cute in an awkward way and will respond to their caregiver with affection. They are still wild animals though. Individuals raising orphaned babies must not treat them as pets. A baby opossum should be raised with at least one other opossum of similar age. This will aid in helping it revert to its true wild nature after being weaned. You must obtain permission from your county game warden to legally possess any wild animal even for a short period of time.

Use good hygiene. Wash your hands after handling the babies and cleaning the cage. Wash bedding and dishes separate from your own. Disinfect bedding and dishes using 1 part bleach to 30 parts water. Allow bedding and dishes to soak for at least 15 minutes then rinse. The information in this paper is brief and intended for raising healthy orphans. If problems develop or you have questions, please contact the Alabama Wildlife Center.

Natural History Information

The Virginia Opossum belong to the order Marsupialia along with many other familiar animals such as kangaroos and koalas. Marsupials are mammals that raise their young in abdominal pouches. The Virginia Opossum is the only marsupial in North America. In Alabama, opossums are found across the state(6).Virginia Opossums are also unique in many other ways. The ends of their tails are prehensile which means they can grasp limbs of trees with it. However, they never hang by their tails. They have opposable thumbs on their hind feet which also aids in grasping and climbing. Opossums have 50 sharp teeth which is more than any other mammal.

Despite the fact that they are well armed, opossums tend to be shy and docile. A characteristic trait of opossums is a behavior called death feigning (or playing possum). In death feigning, the opossum under threat and without a route of escape, will become very still. If the threat continues, it will fall over as if it suddenly died. During this phase of the death feign, an opossum will sometimes drool and give off a foul odor. After the threat has passed, it will recover and continue on its way(2).

Activity: The adult Virginia opossum is almost exclusively nocturnal (active during the night). Activity begins approximately at dusk and peaks between 11:00 pm and 2:00 am. During the cold weather, activity is reduced, but opossums do not hibernate(6).

Habitat Description: Virginia Opossums are one of the few animals that can live almost anywhere. They are commonly found on farmland, in cities, in suburban areas, forests and swamps. They are also one of the few animals that have been able to successfully coexist with humans. Optimal habitats for opossums are forested areas near streams or swamps(2). Opossums will live or den in old hollow logs or trees, abandoned woodchuck burrows, bush piles, wood piles, rock crevices, and drain pipes(6).

Natural Foods:

Adult Virginia opossums will eat almost anything. Their natural diet includes terrestrial and aquatic invertebrates, insects, grubs, carrion (dead animals), and young birds or eggs. Opossums also eat plant food such as acorns, fruits, such as persimmons, wild cherries, and muscadines.

Approximately 80-95% of their diet is composed of animal food and the remainder of the diet is plant food (2,3,6).

Territory/Home Range: Opossums are transient and have a loosely defined home range. They will have multiple den sites and will not necessarily return to the same den site each day (6). However, a female with young will stay at the same den site for several weeks while raising her young but if you don't know where the nest site is, reuniting lost infants can be nearly impossible. The relationships between opossums tends to be passive except during the mating season, and territories are not usually defended as is common with many animals(2).

Breeding Season: In Alabama, the breeding season for the Virginia opossum may begin as early as January and last until September. Studies indicate that mating does not occur during October, November and December. Females can have two to three litters with as many as 11 babies in each litter. Gestation is only 13 days. At birth, the young are less than one inch long. The young clinging to the mother's fur will crawl into a pouch located in a flap of skin on her abdomen. Inside the pouch, the young will attach to a nipple and will remain there for the next two months. There are 13 nipples inside the pouch but only a certain number will produce milk. The number of functional nipples varies per individual but usually ranges from 7 to 11(2).


Baby Opossum Initial Care Record


Reg #:____________ Sex:_____ Age:__________ Wt.:_______ I.D. Mark:__________ Date Rec.:_______

A. INITIAL CONDITIONS (please circle):

1. Temperature: (determine by touch) Normal (101°F) Cold Hot

2. Injuries Present? None Fractures Punctures Superficial Scratches

Ant Stings Bruising (location)__________ Other:___________________

3. Is the baby responsive to touch? Yes No

4. Level of Dehydration (skin turgor, mouth color): 2-5% 5-7% 10% or >

5. Diarrhea? Yes No Bloat? Yes No

B. INITIAL MEDICAL TREATMENT (if any):

1. Sub-Q Fluid Therapy: (warm baby first!) Amount given:______________ Fluid:_________________

2. Antibiotics: Type______________ Route_______________ Amount__________________ Duration______________

BEGIN ORAL FLUID THERAPY ON WARMED BABY

SF Diet? _____________________ Stimulate? _____________ Furnishings? __________________

LRS = Lactated Ringer's Solution F#3 = 1 Cup LRS + 1/2 tube Nutri-Cal

If the baby is dehydrated begin w/ the dehydration protocol. If the patient is a normal, healthy baby skip straight to dilutions.

DEHYDRATION PROTOCOL

*Proceed w/ dilutions if the baby is rehydrated. If not, continue fluids hourly and repeat sub-Q fluids.

Dilutions: 2:1 = 2 parts F#3 + 1 part formula 1:1 = 1 part F#3 + 1 part formula 1:2= 1part F#3 + 2 parts formula up to 2 cc's/feeding

Opossum Developmental Care Chart

Estimated Age 4 – 6 weeks 6 – 8 weeks 8 – 13 weeks

Description Thinly furred, eyes closed, Thinly furred, eyes open, but Eyes open, teeth present but mouth unsealed. Teeth not look sleepy. Teeth emerging. still small. Thicker fur developing present yet. Vocalizing. More active, lots of vocalizing. with guard hairs beginning to emerge by 13 weeks. Body less than 6 inches long excluding tail.

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