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 Post subject: Large Ptyas dhumnades
PostPosted: August 2nd, 2010, 3:58 am 
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Joined: June 8th, 2010, 2:19 am
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Location: Kuching, Sarawak (Borneo)
After posting a bunch of pix of a juvenile Ptyas dhumnades, there was a request for pix of adults. I had posted a series before The Crash, and here they are again. No narrative, but that would cost extra anyway :D

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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 2nd, 2010, 7:26 am 

Joined: June 7th, 2010, 8:52 pm
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Location: Amarillo, Texas
thanks! Those are some neat snakes. Whole genus is awesome


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 3rd, 2010, 1:05 am 
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Joined: June 22nd, 2010, 9:48 pm
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Very cool Hans. I do love me some Ptyas. Judging by the way you're handling it I'd guess they're closer to P. korros than P. carinatus on the temperament scale!


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 3rd, 2010, 2:22 am 
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Location: Kuching, Sarawak (Borneo)
They're very fiery and aggressive for the first few minutes after catching them, but then lose all steam all of a sudden and go practically limp. Very eerie.


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 3rd, 2010, 3:17 am 
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Interesting. My experience with P. korros is that they are extremely whippy and will thrash about when initially grabbed, but rarely attempt to bite. P. mucosus and P. fuscus will thrash and attempt to bite but they are as nothing compared to P. carinatus, a large specimen of which must surely rank amongst the most intimidating snakes in the world. Granted they don't have a significantly venomous bite, but they do have the ability (even at only 7ft or so in length) to launch 6ft up from the ground and bite you in the face (!) and they reach well over 12ft. I have seen long term captive P. carinatus become relatively conditioned to handling, to the point where you can gingerly hold them mid-body, but they are also the only species of snake I've ever seen choose to stand their ground (vipers and other ambush-hunters obviously not included) and fight when given the opportunity of easily escaping. I once spent 45 minutes photographing a 9 or 10ft specimen that charged me every time I came within about a metre of it despite the fact that it was on the edge of rainforest and could escape at any time.


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 3rd, 2010, 3:44 am 
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Joined: June 8th, 2010, 2:19 am
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Location: Kuching, Sarawak (Borneo)
Wow, that sounds like some serious attitude there. I'd love to find one of those in the wild!


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 3rd, 2010, 4:34 pm 
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Joined: June 22nd, 2010, 9:48 pm
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You may get lucky in Sarawak (they occur there)!

I should probably note that the aforementioned episode took place with a snake who had been "behaviourally modified" by three months of stressful milking and other forms of molestation. Here it is being molested by some bald guy:

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They are still more than willing to launch from the ground at your face when you encounter them in the wild (assuming they can't escape - perhaps because you have their tail!) but I think that this particular individual had developed a "grudge" that resulted in all the charging and the refusal to take the easy option of escape (we were trying to return it to the wild when all that took place).

Here's a smaller (WC) specimen at cage-cleaning time demonstrating a typical "about-to-launch-at-the-face" defensive posture:

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Here's me (8 years ago) with the latter specimen for size comparison:

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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 3rd, 2010, 5:19 pm 
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NICE!

Quote:
three months of stressful milking

Milking? Isn't that a non-venomous snake?


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 6th, 2010, 3:16 am 
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Hans Breuer (twoton) wrote:

Milking? Isn't that a non-venomous snake?


Like most "colubrids", asian rat snakes are venomous. In the case of Ptyas, the venom is of reduced complexity and the glands are reduced in size. This is presumably because they have evolved in the direction of big, powerful constricting snakes - in fact they have such large teeth and such strong jaws they can probably kill smaller prey just with their bite (without the action of venom required).

At the time those photos were taken, Bryan and I were milking a lot of different types of colubrids for Bryan's research. Milking colubrids is significantly more difficult than milking "front-fanged" (proteroglyphous or solenoglyphous) snakes and generally involved us putting the animals under anaesthetic and injecting them with pilocarpine to stimulate venom production.


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 6th, 2010, 3:21 am 
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Location: Kuching, Sarawak (Borneo)
Ah yes, Bryan's work on venomous colubrids, how could I forget! How exactly does the venom travel into the victim's body? Does it just run down the teeth, mixed with saliva? Are there any papers/texts on this topic online available for the public?


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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 6th, 2010, 3:42 am 
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Bryan has published quite a few papers in which asian rat snakes get a mention.

This one deals with Coelognathus radiata (which we were milking a lot of concurrently with the Ptyas): http://www.springerlink.com/content/2v1h8up62bfmxbq1/

The best one for all round coverage of the topic though (because it deals with venom-delivery as well) is his recent "Evolution Of An Arsenal" paper:
http://www.venomdoc.com/downloads/2008_ ... rsenal.pdf

From memory (Bryan is obviously the best person to ask), there is no significant (although the rear tooth is ever so slightly enlarged) differentiation in the dentition of the rat snakes ie. they are not "rear-fanged", and there is certainly no grooving on their teeth (they are not "opisthoglyphous"). There are no compressor muscles either of course so I think the venom-delivery system could be described as "primitive" (in the technical, non-derogatory sense). Having said that, they are more than capable of delivering at least some venom, they have no trouble whatsoever breaking the skin (as the photo below proves :D ) and in the case of the Coelognathus I think there is fair reason to believe that the venom is involved in prey capture. Ptyas however, have evolved in a different direction.

A Coelognathus radiatus bite (needless to say their venom is not medically significant to human bite victims):

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These guys (C. radiatus) are fun to play with too:

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 Post subject: Re: Large Ptyas dhumnades
PostPosted: August 6th, 2010, 5:03 pm 
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Location: Kuching, Sarawak (Borneo)
Thank you very much!! Very interesting and educative!! (To my embarrassment, I must admit that I've had the "Evolution of an Arsenal" on my hard drive for quite a while now...never got around to actually read it. But that will change now.)


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