Dinosaurs and the virus [Was simply: Re:]

[Jura <archosaur@reptilis.net>]

>Hello all,

>During college, my interest in Level 4 viruses (the uncurables) brought me to 
>wonder why these types of viruses do not infect reptiles, or if they do, why 
>reptiles do not show symptoms of the diseases they cause. 

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Zoonotic virus studies were never a strong suit of mine. Care to give some 
examples. It is quite possible that reptiles do get infected with these types 
of virus, but I'm not sure of the exact types.

For instance I know that adenovirus is known to occur in a variety of reptiles, 
and herpes is a common viral infection too (though a different strain than 
those that infect humans). I believe herpes is a class 4.

What type of symptoms are you looking for. Lethargy and loss of appetite are 
usually the most common symptoms in reptiles. This is also true for most 
animals. Other symptoms are probably stifled by the animals. No sense 
advertising one's ailments.

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This fostered my interest in herpetology, which recently led to an interest in 
dinosaurs. Given the current "warm-blooded/cold-blooded" dinosaur debate, I 
wondered if it might be possible to consider the idea that IF dinosaurs were 
warm-blooded, the following MIGHT be true:
>
>1. Dinosaurs were susceptible to viruses, like most warm-blooded animals.

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No doubt it would be true, but it would hardly be a sign of "warm-bloodedness," 
for the reasons stated above.

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>2. A level-4-type "dinosaurian" virus may have evolved and infected the 
>dinosaurs, explaining the already-in-process decline of the dinosaurs before 
>the asteroid crash, and explaining the rapidity of their final demise.

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Interesting thought, and one that sounds awfully familiar. Bakker proposed 
essentially the same idea back in the 70s. Apparently continental colides 
allowed for dinosaurian crossover which lead to illness by diseases that could 
now travel to new territory.

The biggest problem I see with this idea is that there is no virus around today 
that has proven itself capable of wiping out an entire species, much less an 
entire class (near class, whatever) of animals. I freely admit to the adaptive 
and infective power of the virus, but I have yet to see one that is *that* 
adaptable.

____________________________

>3. The cold-bloods survived this outbreak because reptiles do not get 
>mammalian viruses.

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Depends on the virus. Reptiles don't get rabies, but then neither do birds. 
This also doesn't explain the other ~75% of life that got wiped out, including 
a large chunk of non-dinosaurian reptiles. Not to mention why mammals & birds 
survived.

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>I know I'm probably sounding like science fiction right now, but there is one 
>more point I'd like to discuss and get your opinions about as well. I've 
>always thought of frogs and toads as the "canary in the coal mine" so to 
>speak. They are very sensitive to changes in their environment, and usually 
>are the first thing to die off in any kind of climactic change. If the 
>asteroid and the following nuclear winter killed off the adaptable dinosaurs, 
>why did the sensitive amphibians survive?

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Because they could adapt better >:)

The key area in this extinction event always seems to be the semi-aquatic 
environments (swamps and such), which didn't seem to suffer any devastating 
losses. If you were completely terrestrial or completely aquatic, you got hit 
hard, but if you were "sitting on the fence" you seemed to scrape by A-OK. As 
many amphibians were known to and are still known to live in these 
environments, then whatever special thing about swamps and the like, allowed 
them to scrape by as well (I believe it has something to do with the versatile 
nature of energy exchange in these environs).

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>Thank you so much for considering my thoughts, and I would love to hear 
>feedback from any or all of you!
>
>Best regards,
>Jomana

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Welcome to the Dinosaur Mailing List. :)

Jura 

http://reptilis.net