Opossum (Didelphis virginiana)

North America’s only marsupial (mammals whose young develop in a pouch). They’re more closely related to kangaroos and koalas than to the other animals in the neighborhood! 

Size: 

4–14 pounds. Body is 15–20 inches long. They often suffer frostbite and lose part of their tails and ears. 

Signs of their presence: 

Sounds: growl, hiss, screech when threatened. 

Evidence of their feeding: Eggs that have been chewed into many small pieces. (Raccoons usually remove one end of the shell without crushing it. Foxes carry eggs away. Weasels and mink crush the entire egg.) Opossums maul chickens beginning at the rear, while raccoons bite their heads off. 

Tracks: look like they were made by little human hands, fingers spread wide apart. 

Scats: are semi-liquid and don’t last long. Left everywhere, even in the den. When scared, possums may secrete a smelly, greenish fluid out of their rear end. 

Diet: 

Opportunist. Opossums eat mostly meat (mainly insects or carrion) but they also eat many plants, especially fruits and grains. They may eat garbage, compost, pet food, bird seed, bird eggs, and young birds (turkeys, chickens, geese, and game birds). They also eat voles, shrews, worms, and toads. 

Typical activity patterns: 

Social style: Solitary. 

Daily activity: Usually nocturnal. 

Hibernator? No, but does den up for days at a time when the weather is bad. 

Migrates? No. 

Where found: 

Opossums are found throughout New Jersey. They can be found in rural, suburban, and urban areas such as parks. Meaning, opossums can live anywhere where food, water, and shelter are present.  

Habitat:  

Wide ranging—arid to moist, woodsy to open, but more common near streams and swamps. Dens in a different place three out of four nights (except in the cold of winter). They find shelter under buildings, in brush heaps, hollow logs or trees, old crow or squirrel nests, and rock crevices. Opossums may share quarters with woodchucks, skunks, and rabbits. 

Territory and home range: 

Not territorial. They have constantly shifting home ranges and may be considered nomadic. Home range is usually 10–50 acres. 

Breeding habits: 

Pair bonding style: Polygamous. Females raise the young alone. 

Breeding dates: February–June. Most females, though, have just 1–2 litters per year. The young are born about 13 days after breeding. 

Litter size: 6–16, average 8. 

Life in a pouch: The tiny (about 1/2″ long) young are born blind and helpless. They must crawl into the mother’s pouch and attach to a nipple. They’ll remain in the pouch for 7–8 weeks, firmly attached to that nipple. Then, for about two weeks, they’ll begin to explore the world, often riding on the mother’s back. They’ll return to her pouch to nurse. They’re weaned at about 3 months old and are generally fully independent by the time they’re seven inches long. 

Amount of time young remain with parents beyond weaning date: 3–4 weeks. 

Common nuisance situations: 

Opossums can be a nuisance throughout the year in various manners.  

Situations in which opossums are causing a nuisance include: 

Raiding gardens, chicken coops, bird feeders, pet food, and garbage. 

Denning in the garage or attic and creating a mess. 

Causing horses to become lame through a parasite in their fecal matter 

A parasite found in the feces of opossums can contaminate water and food sources for horses (both hay and feed). 

 This parasite can transmit a disease to horses, called “equine protozoal myelitis.” This disease affects the nervous system and can cause the animal to become lame. 

Being a vector for diseases harmful to humans and pets.  

These diseases include mange and rabies. 

Not all opossums have rabies 

A hissing or drooling opossum is not necessarily rabid. When threatened, a healthy opossum may bare its teeth, make a lot of noise, drool, bite, or leak a nasty fluid out of its rear. Stress may cause them to play dead, which might confuse predators and keep them from being eaten. 

Legal status in New Jersey: 

Protected. Furbearer species with closed hunting and trapping seasons.  

Those suffering from damage caused by an opossum can take the animal at any time of the year.  

Best practices 

Opossums tend to move around often, and usually don’t stay in one den site. Through modifying the habitat, the opossum may move on to find a more suitable place to live.  

Trapping the opossum: 

An opossum rarely will turn up an easy meal. 

Setting a live trap where they have been active can often alleviate the issue 

Remove food sources: 

Put trash out in morning instead of the evening. 

Opossum-proof garbage cans with a tight-fitting lid, or secure it with straps. 

Don’t leave pet food out at night. 

Feed pets inside 

Enclose compost piles in a framed box using hardware cloth; in a sturdy container, such as a 55-gallon drum; or in a commercial composter. 

Keep the area under bird feeders clean. 

Remove shelter: 

Remove brush piles and debris from the lawn. 

Close garage doors at night. 

Patch any holes in barns, sheds, or garages that can act as an entry way for opossums.  

Block entry and exits to under the porch or deck 

Protect vulnerable livestock: 

Close and secure the doors to the poultry houses, and if birds are caged, keep those doors closed, too. 

To keep opossums from climbing over a wire mesh fence, install a tightly stretched electric wire near the top of the fence, about 3″ out from the mesh. 

Install an electric fence around the hen house or use hardware cloth to cover holes and potential entrances. 

Trapping strategies: 

Live traps: 

Opossums are easily caught with cage traps. 

Baits for the traps include fish, cat food, cheese, fruit, or dog food. 

These baits may also attract and lead to the capture of a non-target animal so be prepared to deal with species other than opossums.  

Foot-encapsulating traps 

Traps can be baited with fish, cat food, cheese, fruit, or dog food 

The access opening cannot exceed 2 inches in diameter 

The opossum has to be euthanized in the trap and then disposed of properly or released on the property it was captured on.  

Opossums can be slow, so it’s possible to capture them by hand, or with the use of a catchpole. Grasp the end of the tail (wear heavy gloves because they have sharp teeth). If you’re holding an opossum and it tries to climb its tail to reach (and bite) your hand, lower it to the ground, where it will attempt to crawl away. 

If bitten, contact a doctor and check if the opossum must be dispatched and sent in for rabies testing. 

Assume that a female opossum has young in her pouch during the rearing season (March–August). The females are not likely to retrieve young, so make sure that all her babies are either in her pouch or clinging to her before you release her. 

Lethal traps: 

Body-gripping traps  

Traps cannot have an inside spread greater than 6 inches 

Place traps near a pitch point where opossums are entering the yard or building. Make such pets cannot access the area when the trap is set 

Snares may be used but they must include a relaxing-type lock 

Bait may be used in this type of set 

Preferred killing methods: 

CO2 chamber 

Lethal trap 

Lethal injection of barbiturate, if possible 

Shooting, using a shotgun with #6 shot or larger, or a .22 caliber rifle (heart/lungs shot is preferred). Why are just the heart/lungs shot listed as preferred? The head shot is difficult because opossums have very small brains located in a relatively large skull—and there’s a strong crest on their skull, which can deflect the bullet. See the illustrations on the next page for more information about the head shot. 

Properly targeting a head shot for an opossum is challenging because their brains are much smaller than you’d guess, looking at the size of their heads. Looking at the side of the opossum’s head, imagine a direct line between the eye and ear. Now, aim slightly below that, closer to the base of the ear. Position the gun very close to the head. 

Acceptable killing methods: 

Gunshot to the head (this is a difficult target and should only be attempted by NWCOs who are more experienced and skilled in the use of firearms) 

Stunning and chest compression 

Stunning and exsanguination 

Control Methods that don’t work particularly well, or aren’t legal in New Jersey: 

Set up motion-activated devices such as lights or sprinkles around your house or in areas where opossums tend to visit frequently. 

Spread ammonia or garlic scents in areas frequented by opossums.  

Apply chemical repellents to structures such as gardens and flowerbeds 

Fence off gardens or fruit trees. 

Fence off areas in which an opossum may like to hide in. Such as, under a deck or a shed.  

Foothold traps are illegal in New Jersey 

For information on legal pesticides click the following link, https://www.nj.gov/dep/enforcement/pcp/pcp-regs.htm 

Interesting Facts and Myths 

Not all opossums have rabies 

A hissing or drooling opossum is not necessarily rabid. When threatened, a healthy opossum may bare its teeth, make a lot of noise, drool, bite, or leak a nasty fluid out of its rear.  

Stress may cause them to play dead, this can confuse predators and keep them from being eaten.