Virginia opossum

Species 

Didelphis virginiana Order: Didelphimorphia Family: Didelphidae

Overview 

Virginia Opossums are relatively large, and thus easy for audiences to see. They are native to North America, and are the continent’s only native marsupial. They can be trained to kennel, target, station, nail trims, and perform A-B behaviors, to name a few. Unreleasable individuals may be obtained through rehabilitators but check specific state laws. While they can be an interesting addition to an ambassador collection, keep in mind that they have a short life span (2-4 years in human care), and some individuals may have a propensity to bite. The potential for zoonotic disease makes them a poor choice for those looking for an animal that can be touched by the public.

Natural History Information

Range and Habitat

Virginia Opossums are found in North America, from New Hampshire west to Colorado, and southern Ontario south to Costa Rica. They prefer moist wetlands or thick brush near streams and swamps, but are found in a variety of habitats, including urban areas.

Longevity

Average lifespan is 2 to 3 years.

Ecosystem Role

They are omnivorous scavengers and are known for their ability to eat ticks. 

 

Husbandry Information 

Housing Requirements

Life Cycle Natural History Relevant Information 

  • Nocturnal
  • Adapted to be both terrestrial and arboreal
  • Short life spans; may need to reduce climbing structures as they age

Habitat

  • Blank Park Zoo: Enclosure is a tall, rolling cage 3x3x6 with shelves and a crate/box for hiding. One female liked to curl up in blankets and towels.
  • Zoo Atlanta: Houses opossums outdoors year round. Enclosure sizes:10x10x8 and 9x6x8. Animals are housed separately. Climbing structures are provided and utilized regularly. Opossums consistently use a litter box with a small amount of water in it, reducing the need for frequent substrate changes. Hide boxes are equipped with heat pads and towels for cold weather. Ice packs and fans are utilized in the heat.

Temperature, Humidity, Light Cycles 

  • Temperature
    • Zoo Atlanta: Heat lamps are provided at temperatures of 25 F or lower. At temperatures of 35 F, extra bedding materials provided (towels for behind the scenes animals, leaves for on-habitat animals). Opossums are provided with a nest box that is about 4 feet long to provide choice to sleep directly under the heat or away from it. At temperatures of 85 F and above, opossums are provided with a frozen water bottle wrapped in a towel.
  • Humidity:
  • Light

Substrate 

  • Zoo Atlanta: Use mulch substrate (turning it 3-4 times per week depending on weather) or dry deck material. 

Other General Housing Requirements or Management information 

Diet Requirements

Diet in the Wild

  • In the wild, the majority of the diet is invertebrates (including ticks) and carrion. Virginia Opossums also eat lizards, frogs, mice, rats, young rabbits, fruits, nuts, seeds, and grasses.

Diet under human care 

  • Blank Park Zoo:
    • 0.1 Virginia Opossum
      Monday, Wednesday & Friday AM & PM
      18g Science Diet Light Adult Dog Food
      ½ of a Capelin
      1 Cricket AM; 1 Mealworm PM
      1 tsp Canned Dog Food (Science Diet Light)
      3g Kale
      5g Banana or Apple
      5g Melon or other low sugar fruit
      2g Cucumber
    • Same diet on Sunday, Tuesday, Thursday and Saturday except replaced banana or apple with 10g Romaine lettuce and replaced cucumber with 2g carrot
    • ENRICHMENT – 6 g of vegetables 3X a week, Once a week boiled egg (if given, do not give canned dog food), Fruits and Vegetables – cantaloupe, orange, coconut, onion, tomato, watermelon, pumpkin, yam, strawberry, broccoli, corn; other enrichment items – jello, honey (very small smear), nightcrawler, mixed nuts (if given do not give canned dog food), pinky, 1 grape
  • Happy Hollow Park and Zoo:
    • 3 oz. maintenance (i.e., low fat) premium brand dog food (like Nutro) and 4.5 oz. chopped mix daily. The mix is whatever is available at the commissary, and can be any combination of fruits and veggies.
    • 3 mealworms or crickets and half a hard-boiled egg three days a week
    • 1 mouse once a week
  • Nashville Zoo:
    • Mazuri omnivore — 30 to 50 grams, total. In the past, we have given Mazuri exotic feline small and dry dog food as well, but omnivore is preferable
    • Variety of produce, including turnip greens, sweet potato, papaya, grapes, melon, broccoli, kiwi, apple, and any other seasonal produce available, offered in small amounts, for variety — 70 to 90 grams, total
    • Nightcrawlers
    • Enrichment food: small amounts of egg, crickets, wax worms, or mealworms
    • Training food: VERY small amounts of Bird of Prey mean, peanut butter, honey, crackers, cereal — 2 to 10 grams for both training and enrichment foods
    • If we have young animals that are growing, we will also offer fish and yogurt
  • Zoo Atlanta:
    • Purina One dog chow (38%), Mazuri omnivore (2%), 12% apples/banana (12%), 26% squashes/carrot/sweet potato (26%), 12% crickets/superworms (12%), ½ T cat food (10%). Once a week, they get 1 tsp yogurt and ½ a hard boiled egg. They receive 2 T of baby food per week.

Veterinary Concerns

  • This species has a strong tendency toward obesity so careful diet management and regular exercise are important to maintain a healthy condition.
  • Opossums can be susceptible to metabolic bone disease, which is caused by poor nutrition.
  • Consumption of pill bugs can result in intestinal parasites (acanthocephalans). Veterinarians should be consulted about proper treatment, but ivermectin has been used. Pill bugs can be treated with diatomaceous earth, though such treatment can have limited effect in humid and/or rainy climates.

Enrichment & Training

Enrichment 

Behavioral Relevant Information

  • They have a keen sense of smell.
  • They will self-annoint.

Environmental Enrichment 

  • Climbing structures

Behavioral Enrichment

  • One individual loved to go outside and take long walks. Walks were done for weight loss. She was partially or mostly blind so there were no concerns about her getting away. Keepers had to watch for rabbit poop, which she liked to eat.
  • Providing leaves or papers allows opossums to kick them with their hind feet and gather them in their tail, then carry them home for bedding.
  • Zoo Atlanta: Cat and dog feeder toys, such as SlimCat Feeder Balls and Outward Hound Slow Feeder Bowls, have been successful at providing intellectual challenges to access food. We also provide opportunities to self-anoint. Our opossums may switch kennels during training, or get time where they can run around an indoor area with boxes and other items to interact with. Where another opossum has left scent, our opossums will “slub” and self-anoint. Other unusual scents may or may not elicit the behavior.

Schedule 

  • Zoo Atlanta: All food is offered in feeder toys for our younger opossums. Opossums receive scheduled enrichment 4x a week in addition to training and programming.

Other Enrichment Resources

Training

Behaviors Trained

  • Due to their limited vision, target training can be difficult. Some facilities have used some scent, or a rattle integrated into the target stick.
  • Zoo Atlanta: Opossums are trained to voluntarily kennel. They go on programs only if they voluntarily kennel. They are also trained in an A-B behavior for shows, and trained to be held for encounters and shows. One younger individual was harness trained, but as programming needs evolved, this is no longer trained in our opossums.

Reinforcers used & schedule of reinforcement

  • Zoo Atlanta reinforces every cued behavior. Reinforcers include dry dog food, wet cat food, egg, banana, apple, superworms, and crickets. May use any item in diet for training for younger, highly motivated opossums. Opossums receive reinforcement for kenneling at home and kenneling at the end of an A-B in programs. For basic animal encounters, food is offered just as being picked up, to reinforce the pick up.

Other

Social Housing/Colony Management

  • Virginia Opossums are nocturnal, solitary, and anti-social, either avoiding others of their kind or acting aggressively towards them.
  • Vocalizations include hisses, growls, screeches, clicking, and lip smacking. The latter two are used by females to communicate with their young, and by males in aggressive displays during mating season. The lip smacking seems to start at sexual maturity.
  • Zoo Atlanta: It is possible to house siblings together while still young but separate within the first year  to prevent aggression.

Colony or Breeding Management

Individual Identification 

  • They may have different color patterns, different patterns on ears or at the base of their tails, or can be marked with Sharpie on their tails if not easily distinguished. 
  • Adults are typically housed separately, so an easily distinguishing mark may not be necessary.

Programmatic Information

Messaging Themes 

  • Adaptations – prehensile tail, hallux; nocturnal adaptations include keen sense of smell, beady eyes, smaller ears, whiskers, long nose, black/ white coloration; pouch for young, as older cling to mothers fur
  • Food web – scavenger, omnivore
  • Habitats – found in a variety of habitats, including urban areas
  • Defenses – will run away, hiss, “play dead,” and defecate/urinate on self
  • Get outside and explore nature- Virginia Opossums are native to North America. Guests can be encouraged to look for animals in their backyards, including our only marsupial. 
  • Create backyard habitats- Many view opossums as pests, but they play a vital role in managing insect and tick populations. Guests can be encouraged to plant native plants and refrain from using chemical pesticides that can be harmful to insectivores. 

Threats and Conservation Status

  • Common predators include foxes, coyotes, Great Horned Owls, and Barred Owls. Humans hunt Virginia Opossums for their fur (which is not considered particularly valuable but can still be used for trimming) and for their meat (which many consider a delicacy.) They have no special conservation status.

Interesting Natural History Information

  • The Virginia Opossum is the only living marsupial in North America. The young develop in their mother’s pouch, which is on the mother’s abdomen.
  • The opossum is probably most known for “playing possum” When threatened an opossum will hiss and show their teeth. If this doesn’t work they will defecate on themselves. They will then go unconscious for around 4 hours.
  • Use opposable thumbs (sing. hallux, plural halluxes/halluces) on their back feet to help grasp onto branches.
  • Important scavengers. 
  • They have 50 teeth, the most of any North American land mammal. The dentition shows the adaptability of eating many items.
  • Females can have 2-3 litters per year with an average of 7 young, though up to 20 babies is possible. Not all babies will survive, and some may not even make it into the pouch. 
  • When the baby is born it is the size of a rice grain; it will crawl into the mother’s pouch where it will live for 50-65 days. 
  • Virginia Opossums are able to hang from their tails only when they are young – full-grown adults are incapable of supporting themselves by their tails. Normally, the tail is used for gathering leaves and branches for nesting material

Did you know…

  • Opossums are not the same thing as possums. Opossums range from North America to southern Argentina and contain 15 genera with over 60 species. Possums are found in Australia with over 20 species. They are all marsupials, but opossums and possums are only distantly related within the same subclass. Possums were named by Captain Cook’s botanist due to their resemblance to the Virginia Opossum.
  • Virginia Opossums have 50 teeth – more than any other North American mammal.
  • Opossums were named by Captain John Smith in 1612 after an Algonquian word that means “white animal”.
  • Scientists studying ticks and opossums found that opossums groomed off and ate over 90% of the ticks on their bodies. Based on this, they estimate one opossum may eat about 5000 ticks in one season.

Opossum in hand

Handling & Presentation Tips 

  • Variation in temperament has been noted at several institutions. Some animals seem to have a more easy-going temperament and tolerate handling well while others gape and sometimes bite while being handled. This did not seem to be strongly tied with sex or if an animal had been neutered. It may be best to look for animals that are less reactive when young and then desensitize them to the presence of humans and with positive reinforcement training.
  • The bite delivered by an adult opossum is potentially very damaging. It is important to wear thick gloves if handling an animal that may be likely to bite. Even with thick gloves on, expect bruising.
  • Seneca Park Zoo: We have had both rehabbed adults and hand raised ones. The rehabbed adults needed gloves to be handled but rarely attempted to bite. The hand raised ones were very imprinted and tamed. There was no need to wear gloves. We also found that females are more friendly than males.
  • Natural Science Center of Greensboro: Males can get bitey.
  • Zoo America: We’ve had biting issues with males, so we prefer females.
  • Blank Park Zoo: We did not have a problem with biting but our vet recommended/required us to use gloves due to leptospirosis.
  • Zoo Atlanta: We present opossums in the hand. We use a flat hand/arm presentation and allow the animal to stand on the forearms. We have harness trained one opossum who did not tolerate being handled when he was younger and he can now be presented on leash or in the hand. We use gloves to handle one animal that was a biter when he was younger. We have used neutered males, intact males, and intact females for presentation.We offer treats to our opossums as we pick them up. We have found that they now usually wake when their names are called and approach the handlers readily. This is not generally the case if it is very cold out and they are snuggled in their nest box though.
  • Denver‌ ‌Zoo:‌ ‌‌Opossums‌ ‌are‌ ‌presented‌ ‌on‌ ‌a‌ ‌rolling‌ ‌cart‌ ‌(these‌ ‌are‌ ‌elevated,‌ ‌which‌ ‌sometimes‌ ‌helps‌ ‌with‌ ‌the‌ ‌viewing)‌ ‌with‌ ‌stumps–those‌ ‌are‌ ‌the‌ ‌”touching‌ ‌platforms.”‌ ‌We‌ ‌deliver‌ ‌food‌ ‌on‌ ‌these‌ ‌stumps‌ ‌and‌ ‌they‌ ‌can‌ ‌walk‌ ‌around‌ ‌the‌ ‌cart,‌ ‌but‌ ‌are‌ ‌only‌ ‌touched‌ ‌(and‌ ‌fed!)‌ ‌on‌ ‌the‌ ‌stump.‌

Use Guidelines 

  • Zoo Atlanta: Requires handlers to wear gloves to prevent nipping as handlers are offering food while picking them up. 

Public Contact and Interaction Guidelines

  • Zoo Atlanta: We do not allow the public to touch opossums due to the variety of potentially zoonotic parasites and diseases (e.g., leptospirosis) they are known to carry.
  • Henry Vilas Zoo: Our opossums are non-contact for the public.

Transportation Tips

  • Zoo Atlanta: We use kennels that are both top and front loading. Front loading allows opossums to kennel voluntarily and exit voluntarily for A-Bs. Top loading allows opossums to be easily picked up from and placed back into the kennel for programming where opossums will be presented on the hand. A kennel cover is used at colder temperatures to keep animals warm and in rainy weather to keep them from getting wet.

Crating Techniques 

  • Zoo Atlanta: Our opossums are crate trained. If opossums do not voluntarily kennel, they do not go out on a program. We use a top-loading kennel for removing an opossum from the carrier so that no one is reaching toward their face. 

Temperature Guidelines 

  • Zoo Atlanta: Currently uses opossums for outdoor programming for no longer than 30 minutes at temperatures between 35 and 90. If below 35, opossums can be presented only inside and must have a kennel cover during transport outside.

Acquisition Information 

Marsupial and Monotreme TAG

Program Leader (as of 2020): Ms. Christana Hamlin Andrus chamlin@sandiegozoo.org

 Look for specialty/exotic rescues such as:

  • Local rehab centers
  • Zoo Atlanta: Georgia law requires releasable animals to be released so we are notified of young animals that cannot be released due to human habituation. We also have acquired wild caught youngsters from other states.

Resources 

Contributors and Citations 

  • The Philadelphia Zoo
  • Happy Hollow Park and Zoo, San Jose
  • Nashville Zoo at Grassmere
  • Zoo Atlanta
  • Houston Zoo, Natural Encounters
  • Seneca Park Zoo
  • Blank Park Zoo
  • Denver Zoo
  • CuriOdyssey
  • Henry Vilas Zoo
  • Natural Science Center of Greensboro
  • Zoo America

Comments from the Rating System 

Photo Credits: 

Credit for top photo, single opossum: Emily Bobal at Zoo Atlanta

Credit for second photo, opossum in hand: Zoo Atlanta

Credit for bottom photo, young opossums: Emily Bobal at Zoo Atlanta