The North American opossum with winter coat (Wikipedia)
The opossum (Didelphimorphia) is the largest order of marsupials in the Western Hemisphere, including 103 or more species. Commonly called possums, the word “opossum” is borrowed from the Virginia Algonquian (Powhatan) language and means “white dog” or “white animal”.
Most opossums have a plantigrade stance (feet flat on the ground) and the hind feet have an opposable digit with no claw. Like some monkeys, opossums have prehensile tails.
Female opossums have a pouch, called a marsupium. While the females do have a placenta, it is short-lived, simple in structure, and not fully functional. The young are therefore born at a very early stage and must find their way into the marsupium to hold on to and nurse from a teat.
Female opossums often give birth to very large numbers of young who are weaned between 70 and 125 days, when they detach from the teat and leave the pouch. The opossum lifespan is unusually short for a mammal of its size, usually only two to four years. Senescence is rapid.
When threatened or harmed, opossums will “play possum,” mimicking the appearance and smell of a sick or dead animal. This physiological response is involuntary, rather than a conscious act. The opossum’s lips are drawn back, the teeth are bared, saliva foams around the mouth, the eyes close or half-close, and a foul-smelling fluid is secreted from the anal glands. The stiff, curled opossum can be prodded, turned over, and even carried away without reaction, but the animal will typically regain consciousness after a period of between 40 minutes and 4 hours, a process that begins with slight twitching of the ears. In the case of baby opossums, however, the brain does not always react this way at the appropriate moment, and therefore they often fail to “play dead” when threatened.
These ungainly-looking animals with sharp teeth are actually quite remarkable.
Opossums have a remarkably robust immune system, and show partial or total immunity to the venom of rattlesnakes, cottonmouths, and other pit vipers. Opossums are about eight times less likely to carry rabies than wild dogs; only 1 in 800 opossums is infected with rabies.
Opossums are also mortal enemies of the tick that infects humans with the terrible Lyme disease.
John Ferro writes for the Poughkeepsie Journal, March 16, 2015, that opossums dine on ticks “like a vacuum dines on dust”:
The tiny adolescent ticks that carry Lyme disease bacteria are most active during the late spring months, typically May and even as early as April during warmer years.
But whereas these ticks can be found in large numbers on mice, shrews and chipmunks, they are eaten in large numbers by opossum.
Research led by scientists based at the Cary Institute of Ecosystem Studies in Millbrook placed different species into cages, covered them with ticks and waited for the biting arachnids to jump off.
The scientists then counted how many survived.
Opossums can eat or remove as much as 96 percent of the ticks that land on them.
Research also suggests the immune system of opossums is fairly effective at fighting off the disease. […]
Opossums are your friend and mine in the fight against Lyme.
Opossums are usually solitary and nomadic, staying in one area as long as food and water are easily available. As nocturnal animals, they favor dark, secure areas below ground or above.
The Virginia opossum was once widely hunted and consumed in the United States.
So the next time you see an opossum, be thankful that it’s around, because where there’s opossum, ticks will be scarce!
H/t FOTM’s CSM