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Archive for the ‘Marsupials’ Category

yapok

The yapok or water opossum is a marsupial that ranges into Mexico and Central America.

Americans are an unusually insular sort of people. We fail at geography big time. Don’t ask the average American what the capital of Canada is.  Don’t tell tell us that Mexico City is the largest city on the continent.

“Because Mexico ain’t on our continent!”

That attitude even affects how we view nature.

When I was a little boy, I accepted without any question that North America’s only marsupial is the Virginia opossum.

It seems this claim is so widely-accepted that it is usually mentioned within the first sentence of any description of the species.

There is, of course, a big problem with this description. North America isn’t just the US and Canada.

This is North America:

North America

Yes. All that territory from Mexico to Panama is part of North America, and in those countries, there are multiple species of marsupials. Central America has 11 species. Mexico alone has has 8!

It is correct to say that the only marsupial in the US and Canada is the Virginia opossum, but it is geographical ignorance that only an American could conjure that says the Virginia opossum is the only marsupial found on the continent.

So when you see someone saying that Virginia opossums are the sole representatives of marsupials on this continent, realize that this person hasn’t thought through what he or she is actually saying.

Or is totally unaware that there isn’t continent between “North America” and South America.

There is also a subconscious racism at work, which sees only a community with Anglo-America as the true North America and casts aside that which lies to our south as being the other.

It may all be a silly little thing, but it grinds my gears.

And when we write about nature, we need to be more careful with our language.

 

 

 

 

 

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pig-footed bandicoot

I think it’s really hard for those of us in the Northern Hemisphere to understand what special place Australia is in terms of biodiversity.

It is largest area in the world that has been isolated from the rest of the continents long enough for evolution to take an entirely different course, but when Europeans came, so much of the biodiversity wound up disappearing. Unfortunately, this is still going on.

One animal I wish we’d been able to study more closely before it became extinct is the pig-footed bandicoot (Chaeropus ecaudatus). This animal was a bandicoot that had evolved something similar to cloven hooves on the front feet. Cloven hooves, are the trademark of the Artiodactyls, the very successful group of placental mammals that includes cows, sheep, goats, deer, and pigs. But here was a bandicoot that had them on its front feet. Its hind feet had a single “hoof,” with two vestigial toes higher up the leg, which were almost like the double dewclaws of a Great Pyrenees or Beauceron.

No other animal, placental or otherwise, has produced such an unusual toe arrangement.

We know very little about this animal. It was rare when Europeans arrived. It’s gone now. We don’t know what killed it off. Cats usually get the blame. The end of aboriginal burning also gets pointed out. Burning created areas where new shoots could pop up, and this omnivorous animal was able to us those areas as its main habitat.

The truth is there just so much we don’t know. There is even debate about how well this animal actually moved and why it would evolve such unusual toes.

We have eye witness accounts, and the animals were reported to be alive as late as the 1950s. But not enough zoologists were interested in them at the time, and they were exceedingly rare. So we’ve got horrible gaps in knowledge about them.

This actually isn’t that unusual. Look up the literature on marsupial moles, which are similarly quite rare and horribly under-studied.

Because the pig-footed bandicoot went extinct only in the 1950s, there is actually a bit better chance that there might be a few living out in some remote region than there is for extant thylacines. For some reason, this animal has never captured the imaginations of any naturalists in the same way the thylacine has.

But here we have a sort of marsupial “chevrotain,” which is every bit as interesting as a marsupial “wolf.”

Parallel evolution is always pretty cool.

It’s a shame that species go extinct before we can learn about them.

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Got this ‘possum in cage

It’s a little female Virginia opossum.

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The much ballyhooed prehensile tail:

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Remarkable discovery in the snow!

Thylacine sighting

 

 

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Old opossum

old opossom

I get opossums on the trail camera fairly regularly, and because I find them somewhat less interesting than other animals, I usually don’t post their photos on here.

This one, however, is kind of interesting because it has the features of a very mature individual. Now, keep in mind that Virginia opossums don’t live very long, even though they are about the size of a domestic cat. In captivity, their record longevity is a measly four years.

But this individual is at least on its second year.  The frostbitten ears suggest that it has survived more than couple of very hard freezes.

As opossums mature, they get a lumpy head profile.  When they are younger, they have a more collie- or borzoi-like head, but as they get up in years, this starts to change.

This opossum is the most primitive mammal north of the Rio Grande, and when I say this, I don’t mean that it’s primitive because it’s a marsupial. It’s actually a primitive marsupial, meaning that it looks very much like the earliest mammals that gave rise to all marsupials. Indeed, it is so primitive that the similarities between New World opossums and the West Indian solenodons are pretty striking. The two species of solenodon retain many primitive features of the ancestral placental mammals, and it would make sense that the primitive opossums and primitive solenodons would look somewhat similar to each other.

Beyond their taxonomy, there aren’t really that many amazing things about opossums. They don’t have very complex behavior.  There are claims of them having amazing intelligence that one can find online, but these clams are not born out in reality.

The thing is, you don’t have to be too smart if you can eat just about anything and reproduce by having dozens of offspring every year.

And even though they are primitive, natural selection has still worked its ways on their kind, but it’s just not change them as much as it has us, coyotes, or red kangaroos.

 

 

 

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An old opossum

This old opossum is a survivor. It looks like it even has a bit of frost bite on the ears from last winter.

old opossum 

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Intelligent “dog with hands” versus primitive (and quite stupid) marsupial:

Source.

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