12 January 2018

Opossums, Continued

Welcome back to Warren’s Notice. Continuing last week’s blog post, Learning About Opossums, I had just described looking out the window in the early afternoon to see an opossum followed by Vicki’s cat Mindy. I’ve no idea if Mindy spotted the opossum out foraging, or if Mindy happened upon the opossum’s transient home and chased the animal out into the open.

I first saw the two on the northwest side of our building. Switching windows, I watched the opossum walk steadily around to the south side, with Mindy about 10 to 20 feet behind, sort of stalking, sort of just acting curious. I finally lost sight of the opossum around a pile of branches. Presumably, Mindy got too close as I saw her running away.

Enough. I’d better get on with what else I learned about opossums.

Diet 

Opossum dining in a
trash can.
(Multiple websites)
Opossums are opportunistic omnivores, eating whatever they find. Considered sanitation workers of the ecosystem, they dine on dead animals, plants and fruit; insects, earthworms, snails and grubs; and may hunt small rodents, birds and chicks, frogs and snakes. They apparently have partial or total immunity to venom from rattlesnakes, cottonmouths and other pit vipers.

Breeding and Offspring
Opossum breeding season is generally between January and July, though it varies somewhat with geographic location. The gestation period is short, 12 to 13 days. Females (“jills” as opposed to “jacks”) may deliver 1 to 3 litters of 4 to over 20 “joeys,” 1 to 3 times a year; two litters of 4 to 9 is most common. Newborn joeys are about the size of honeybees.


Orphaned baby opossums in dead mother’s
pouch.
(Photo from www.2ndchance.info/raisepossum.htm)
No more than 13 joeys from the large litters survive because the mothers have only 13 nipples. Observations vary but the joeys are normally weaned by 60 to 90 days. On leaving the pouch, they stay with their mother, initially clinging to her, until they are on their own no later than 4 months from birth. 

Young opossums cling to their mother
after leaving the pouch.
(Multiple websites)
The young opossums are vulnerable to predators. Vicki’s cats, for example, would likely go after very young opossums should they wander or be pushed from the pouch.

Defense

Opossum threatening with
all 50 teeth.
(Multiple websites)
Despite having 50 teeth, the most of any mammal, opossums are shy and non-aggressive. When threatened, they may run, growl, hiss, screech, arch their back with fur erect, bare their teeth, drool, urinate and defecate.

They can bite, of course, but if all else fails, they normally faint and play possum, an involuntary response that gives the appearance and odor of a sick or dead animal. They roll onto their side, become stiff, close their eyes or stare, and bare their teeth, tongue hanging out, as saliva foams around the mouth and a foul-smelling fluid is secreted from anal glands. They may remain in this state for minutes to hours.
 

Opossum playing possum.
(Multiple websites)
Health Concerns
Opossums tend to be very clean, spending much of their time grooming like domestic cats. A 2014 research study that exposed several wild animals to Lyme-disease carrying ticks labeled opossums the winner at ridding the world of ticks. The opossums licked off and swallowed over 90% of the ticks.

Although there have been cases of opossums with rabies, it’s a rare occurrence. Their resistance to rabies is thought to be related to the opossum's low body temperature (94-97°F) and strong immune system.

Opossums are known to carry a variety of bacterial and viral diseases, such as equine protozoal myeloencephalitis, which mostly affects horses when they ingest feed or water contaminated with opossum feces.

Wrap Up
Opossums should be left alone. They are not cut out to be pets.


If one remains in your area or keeps returning to it, try to eliminate the attraction, which can be challenging. Opossums scored better than cats, dogs, rats and rabbits on ability to remember. They tend to outcompete other creatures for food. Remove any food, keep doors and windows closed, and leave an outdoor light on.
Logo of the Opossum Society
of the United States.

If help or information is needed, contact a wildlife rehabilitator or the Opossum Society of the United States (see P.S.), whose members are dedicated to opossum rehabilitation and education.

Thanks for stopping by.

P.S.
Opossum vs possum: writingexplained.org/opossum-vs-possum-difference
Selected background references:
www.havahart.com/opossum-facts
www.ksre.k-state.edu/news/stories/2016/03/awesome-opossums030116.html
www.esf.edu/aec/adks/mammals/opossum.htm
www.outwitcritters.com.vhost.zerolag.com/possum/index.html
en.wikipedia.org/wiki/Opossum
Study of opossums’ ability to kill ticks: www.caryinstitute.org/newsroom/opossums-killers-ticks
Opossum Society of the United States: opossumsocietyus.org/