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urbpan ([personal profile] urbpan) wrote2010-08-03 10:08 pm

50 More Urban Species #23 Virginia opossum; Urban Nature pictures 7/22


Virginia opossum Didelphis virginiana

South America was once an island continent, full of weird and wonderful marsupial mammals. Continental drift, changing ocean levels, and volcanic activity where Panama is now, brought North America into contact with it, and both places were changed forever. Placental mammals streamed down into South America and wiped out most of the marsupials. Some South American mammals made their way up the narrow passageway through Central America and into North America. Only the hardiest and most generalized scavengers had the stuff to compete with the North American animals. Today the Virginia Opossum is the only marsupial found in North America. (The nine-banded armadillo, a member of the strange mammal group that includes anteaters and sloths, is another creature that went north in the Great American Interchange.)

The Virginia opossum was limited to the American south at the time of European colonization. The creation of human-provided year-round shelter and food sources allowed the animal to expand further, reaching New England at about the turn of the 20th century. In another 80 years or so it reached the Canadian border. Accidental or deliberate introductions have created new populations of opossums on the west coast of North America.

The opossum can thrive in nearly any kind of habitat, and does well in urban areas where medium-sized predators tend to be scarce. Coyotes prefer not to feed on opossums if there are other prey animals around, and opossums can defend themselves convincingly against most smaller creatures. Showing 50 sharp teeth with a guttural drooling hiss, they can be scary when cornered. If they are pressed further they will perform their famous feigning death routine, fouling their fur with rank excretions from their cloaca. None of these defenses deter a speeding car, the creature an opossum is most likely to encounter on its nocturnal carrion-foraging missions. The Virginia opossum is among the most common roadkill animals across its range for these reasons.

Being marsupials, opossums have a lower body temperature than other mammals, and they subsequently seem to be unable to carry the rabies virus. In some parts of their range opossums feed largely on snakes, and are thought to be somewhat resistant to rattlesnake venom.

Their bare and prehensile tail is distinctive, and reports of cat-sized rats may be misreported opossums. In cold places, these animals will lose the tips of their tails and their naked ears to frostbite. This can be a way to identify an opossum that has lived a very long life, since most do not live past a single year. Even opossums living in captivity rarely live past three. However they can breed young, and each female can potentially raise 13 offspring--one for each nipple. The embryo-like babies crawl from cloaca to pouch and attach there until weaned.

A road-killed mother opossum may have living young still attached in her pouch. Wildlife rehabilitators have been known to successfully raise these babies. Sometimes when grown, these opossums are tame enough that they are used by wildlife educators as living ambassadors, to teach people about how strange and fascinating nature can be.


Also they like to be in paper bags.

[identity profile] miz-geek.livejournal.com 2010-08-04 02:44 am (UTC)(link)
I love opossums! I got to know them at the Ohio Wildlife Center, where we usually had at least one in residence. Since they are theoretically able to carry rabies, we were required (by the state of Ohio, I suppose) to keep them for 40 days, even though they usually recovered much sooner from their cuts and scrapes and road rash. They wouldn't get tame, but they'd mellow out a little and stop complaining so much when their cages were cleaned or we put ointment on their wounds. And their tails are really cool. Anyway, they really grew on me :)

[identity profile] tiranna.livejournal.com 2010-08-04 03:00 am (UTC)(link)
This reminds me of a set of opossum videos floating around, like the proper opossum pedicure http://www.youtube.com/watch?v=1MRE2K3x-AY

[identity profile] tiranna.livejournal.com 2010-08-04 03:01 am (UTC)(link)
And as a side note, is their fur as soft as it looks?

[identity profile] urbpan.livejournal.com 2010-08-04 09:35 am (UTC)(link)
It's pretty soft--not as sot as a rabbit or cat's fur.

[identity profile] elizaeffect.livejournal.com 2010-08-04 03:20 pm (UTC)(link)
It's thick and fluffy but iirc it has a rough sort of outer layer that doesn't feel as nice as a cat or rabbit.

[identity profile] barn-swallow.livejournal.com 2010-08-04 03:16 am (UTC)(link)
I always liked them! I have a hazy childhood memory of seeing one hanging from a tree playing dead. I'm not sure if I really saw it or just imagined it haha.

He or she looks much bigger than I expected!

[identity profile] dragonwrites.livejournal.com 2010-08-04 03:47 am (UTC)(link)
yay! great post! informative and entertaining.

[identity profile] roaming.livejournal.com 2010-08-04 05:49 am (UTC)(link)
We have an opossum who comes to our yard in the winter and sleeps in the heated shelter we have out there for our feral yard cat. (Now that that cats is gone, after 18 healthy years, I think I'll leave it up for the possum this winter.)

I think they are so ugly they are cute.

I read somewhere that the "playing possum" thing isn't pretend: they actually go unconscious -- like fainting goats -- and stinky stuff purges from their anus and mouths, as most predators prefer live dinners, not rotting ones. They can be out for as long as four hours! Mostly, whenever I've tried to get the possum out of the shelter (when the cat needed it more), it just freezes and won't move. Once I had to push it away with a broom, practically lifting it with the broom. It just froze. Poor thing. Now that the cat is gone I'll be kinder to it and let it get warm in the heated shelter.

They only live 3 years max, even in captivity? Why is that?

[identity profile] elizaeffect.livejournal.com 2010-08-04 03:24 pm (UTC)(link)
Evolution. Marsupials in general don't live super-long. They age rapidly and even with excellent care their bodies just give out.

[identity profile] gigglingwizard.livejournal.com 2010-08-04 07:21 am (UTC)(link)
They're also drawn to traps set for raccoons, and are the only other animal that size I know of (in eastern Norh America) that will hit on sweet baits. I once had a cage trap in a cubby set for a raccoon, and a 'possum took up residence there. I'd shoo him out and chase him away, and the very next day he'd be in there again. That went on for three or four days.

[identity profile] kryptyd.livejournal.com 2010-08-04 07:42 am (UTC)(link)
I love them, especially since I saw some wildlife rescue programme where a woman had one in her cupboard and called up the wildlife centre terrified that there was a "monster" in there!

And this:

Being marsupials, opossums have a lower body temperature than other mammals, and they subsequently seem to be unable to carry the rabies virus.

is all news to me. Interesting.

[identity profile] wirrrn.livejournal.com 2010-08-04 10:11 am (UTC)(link)

Ha! I laugh at South America for attempting to usurp my homeland as Land of The Marsupial! We have Monotremes *g*

It's common practice here that if you see a roadkilled possum/kangaroo/Chuditch etc, you check the pouch for Joeys...

[identity profile] urb-banal.livejournal.com 2010-08-04 12:44 pm (UTC)(link)
ahhh, cute!

[identity profile] brush-rat.livejournal.com 2010-08-04 02:38 pm (UTC)(link)
Thanks, I really enjoyed this one. The life span was a big surprise.

[identity profile] elizaeffect.livejournal.com 2010-08-04 03:32 pm (UTC)(link)
Oh man, memories. When I volunteered at the Cleveland Museum of Natural History as a teenager there was an elderly opossum (originally rescued off a roadkill mom) you could carry around like a big fat baby. It was so fun.

[identity profile] lexica510.livejournal.com 2010-08-04 05:56 pm (UTC)(link)
Fascinating and very informative — thank you!

(Although I'm still emotionally scarred from encountering one unexpectedly in my apartment's unfinished basement. "Doot doot doo... going into the basement to get some yarn to knit with... OMIGOD WHAT IS THAT IT'S THE BIGGEST RAT I'VE EVER SEEN AND IT'S HISSING AND DROOLING AND WHERE'S THE DOOR???" as I scrambled backward as fast as I could. Took a moment or two before I realized that it was a 'possum, it was nearly as startled as I was, and if I left the window open and the door to the rest of the apartment closed, it would probably leave. Luckily, it did. Otherwise that box of yarn would still be in that basement...)

[identity profile] aemiis-zoo.livejournal.com 2010-08-15 01:46 am (UTC)(link)
You don't look very enthused to be holding that opossum.

[identity profile] urbpan.livejournal.com 2010-08-15 03:46 am (UTC)(link)
I'm very professional (or something).