What are these weird-looking creatures?
It is a Virginia opossum, North America's only marsupial (female has a pouch). The female carries and nurses her young in her marsupium until they are about 2 to 3 months old; then they are carried on her back another 1 to 2 months whenever they are away from the den. They are solitary and nocturnal: usually slow moving; when frightened and unable to flee may fall into an involuntary shock-like state, "playing 'possum."
When threatened or harmed, they will "play possum", mimicking the appearance and smell of a sick or dead animal. The lips are drawn back, teeth are bared, saliva foams around the mouth, and a foul-smelling fluid is secreted from the anal glands. The physiological response is involuntary, rather than a conscious act. Their stiff, curled form can be prodded, turned over, and even carried away. Many injured opossums have been killed by well-meaning people who find a catatonic animal and assume the worst. The best thing to do upon finding an injured or apparently dead opossum is to leave it in a quiet place with a clear exit path. In minutes or hours, the animal will regain consciousness and escape quietly on its own.
Its tail is prehensile. A prehensile tail is adapted for grasping and wrapping around things like tree limbs. The opossum can hang from its tail for a short time. Some people think opossums hang from their tails and sleep. They don't. Their tails aren't strong enough to hold them for that long!
Opossums probably diverged from the basic South American marsupials in the late Cretaceous or early Paleocene. A sister group is the Paucituberculata, or shrew opossums. They are commonly also called "possums", though that term is more correctly applied to Australian fauna of the suborder Phalangeriformes.
It lived during the age of dinosaurs: fossil remains have been found from 70 million years ago.
The Paleocene, "early dawn of the recent", is a geologic epoch that lasted from 65.5 ± 0.3 Ma to 55.8 ± 0.2 Ma (million years ago). The Paleocene epoch immediately followed the mass extinction event at the end of the Cretaceous, known as the K-T boundary (Cretaceous - Tertiary), which marks the demise of the dinosaurs. The die-off of the dinosaurs left unfilled ecological niches worldwide, and the name "Paleocene" comes from Greek and refers to the "old(er) (paleo) – new (ceno)" fauna that arose during the epoch, prior to the emergence of modern mammalian orders in the Eocene.
In other words, these awkward-looking critters are extremely good survivors, despite the fact that they are slow-moving, easy prey for predators and frequent victims of roadkill. Their unspecialized biology, flexible diet and reproductive strategy make them successful colonizers and survivors in unsettled times.
The first description of the opossum in the English language comes from explorer John Smith, who wrote in Map of Virginia, with a Description of the Countrey, the Commodities, People, Government and Religion in 1608 that "An Opassom hath an head like a Swine, and a taile like a Rat, and is of the bignes of a Cat. Under her belly she hath a bagge, wherein she lodgeth, carrieth, and sucketh her young."
Opossums have a remarkably robust immune system, and show partial or total immunity to the venom of rattlesnakes, cottonmouths, and other pit vipers. Thanks to their lower blood temperature, rabies is almost unknown in opossums.
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