Reptile & Amphibian Forums

Hi all

Here is the link for the downloading of the first of the long awaited venom papers on 'colubrids'. This one covers an extensive array of 'colubrids' as well as weird elapids (including little studied Australian ones) and vipers (including Fea's).

Major implications of the paper are:

1. The venoms of the 'colubrids' are just as complex as that of the various elapids and vipers.
2. The toxins in the 'colubrids' are some of the same sorts as found in elapid in viper venoms (we even pulled out the typical cobra-style toxins from bloody ratsnakes).
3. This has the potential to seriously screw up the pet trade.
4. This does however reveal a vast venomous Serengeti for biomedical researchers.

Feel free to pass on to anyone you think might be interested.

Cheers
BGF
Venom paper download

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So does anyone have any good theories on why constrictors like Coelognathus would have venom? I remember hearing theories about it helping digestion, but, then, if it's just a digestive aid it's not really venom, right?

Patrick Alexander

They use it for prey capture. Contrast the behaviour of the Asian 'Elaphe-types' with that of the Americans (which have recently undergone a secondary loss of the gland). The Asians are actually pretty pathetic contrictors but absolutely bite the living crap out of the prey item (quite viciously). The Americans do little biting (other than the intial strike) but are robust constrictors.

The evolutionary key here is that there was no evolutionary selection pressure for the development of fangs unless there was already a potent venom to deliver. Sort of like all primate lineages being able to make noises but we are the only lineage with the highly developed piece of architecture called the voice box.

Venom in the advanced snakes are analagous. The heavy bodied primitive snakes dumped the muscle that was essential for prey capture in order to become more gracile and agile. They needed a new weapon. Enter venom.

Cheers
BGF

`They use it for prey capture. Contrast the behaviour of the Asian 'Elaphe-types' with that of the Americans (which have recently undergone a secondary loss of the gland). The Asians are actually pretty pathetic contrictors but absolutely bite the living crap out of the prey item (quite viciously). The Americans do little biting (other than the intial strike) but are robust constrictors.'

Really? That's nifty... I guess I just don't have enough experience with Asian `Elaphe'. I've been keeping a Coelognathus radiatus for a few years, and he'll just do the typical Pantherophis thing... just one initial strike and a bunch of (apparently quite effective) coils.

Also, though, I remember seeing a paper a while back indicating that constriction rather than venom was the cause of prey death in Boiga irregularis...

`The evolutionary key here is that there was no evolutionary selection pressure for the development of fangs unless there was already a potent venom to deliver. Sort of like all primate lineages being able to make noises but we are the only lineage with the highly developed piece of architecture called the voice box.

Venom in the advanced snakes are analagous. The heavy bodied primitive snakes dumped the muscle that was essential for prey capture in order to become more gracile and agile. They needed a new weapon. Enter venom.'

Makes sense.

Patrick Alexander

`Also, though, I remember seeing a paper a while back indicating that constriction rather than venom was the cause of prey death in Boiga irregularis...'

The paper I was thinking of is:
Hayes-William-K; Lavin-Murcio-Pablo; Kardong-Kenneth-V
`Delivery of Duvernoy's secretion into prey by the brown tree snake, Boiga irregularis (Serpentes: Colubridae).'
Toxicon-. 1993; 31 (7) 881-887.

I thought I had a copy of it, but I can't find it at the moment... thinking about it more, though, I think they just showed that constriction played some part, rather than that it was the whole deal.

Patrick Alexander

My Taiwan beauty seems to be a pretty intent constrictor. But I always make fun of my mandarin rats for mauling their prey into submission and then swallowing it half alive. Seems pretty similar to what my hognose does now that I think about it. Maybe there's something to that. It would make sense for an animal that's only mildly venomous to still use constriction to protect themselves from struggling prey though.

I was quite surprised at how effective the constrictions of E.p.Coxi were. I remember being most surprised though when, he completely let go of the prey with his mouth, looked back at it. Then bit it again and waited a good while before swallowing! Would be an interesting study...

We had a 1.2 meter Psammophis kill seven eyes open fuzzy rats in a row, chewed each only three quick times, then waited. Each died in less than two minutes. A cobra would be happy with those numbers.

Cheers
BGF
Venomdoc Homepage

This is great! thanks for sharing your research with us!

Thank you!!!

Now if I could only find a LC/MS analysis similarly performed for hydrodynastes, my life would be complete.

Hi mate

I did do Hydrodynastes gigas as well but the machine was having a really crap day so the spectrum was pretty ordinary. The venom appeared to be largely similar to Heterodon.

Cheers
B
Venomdoc Homepage

So, does that mean hydrodynastes *is* similar to heterodon, or that further testing is necessary to clarify since the mass spec was acting up?

And, do I understand correctly that there is at least a second paper coming?

Thanks again, this is great reading. I need to learn a whole new vocabulary to follow it, but it's fascinating.

Amazing reading, Thank you for sharing.

Did you ever test Philodryas baroni as I would be intrested to see how they compare.

Shaun

No mate, we didn't get that species (luck of the draw of what actually showed up) but Philodryas as a genus is one that I would treat with considerable respect as they have been well documented in really nasty bites.

Keep in mind, while the non-front fanged snakes are less efficient at delivering the venom (this is of course what drove fangs to be evolved on at least four separate occasions) they still can deliver it and there is no antivenom. SO while the odds of them getting you is less, if they do you're screwed.

Cheers
BGF

The Hydrodynastes looked reasonably similar (same overall trend) but a good spectrum would be of course essential for accurate molecular weights. Like Heterodon, it is very heavy on the big enzymes and less of the peptides.

There are two other papers in the journal food chain (the two Journal of Molecular Evolution papers referenced) that should be out soon. We are just about to submit the fourth and fifth papers and should start writing the sixth soon.

Cheers
BGF

Great paper. Can you point me in the right direction to decipher those spectrums....

Or is it "be careful out there".

Worth waiting for.

Cheers Mark