Evolution in colubrids

Lisa · 08-29-03, 11:52 AM

This was just posted at http://www.**************/toxinology...oidea_RCMS.pdf but for clicking sake i've reposted it @ http://www.geekgrrl.ca/bgf_colubroidea_rcms.pdf . It suggests that colubrids are evolved from venomous snakes which evolved from boids

Dr. Bryan Fry · 08-31-03, 01:36 AM

Actually, it gets even cuter than that. We pulled the classic cobra-style toxin out of a bloody ratsnake. We showed that these, and other viper and elapid types, toxins are diverse in the various different 'colubrid' families. In a nutshell, venom evolved once, just before the viperidae lineage split off (one of the most basal events in the evolution of the advanced snakes (Colubroidea)). From an evolutionary perspective, this is extremely cool.

The ancientness of venom means that all the lineages we think of as 'colubrids' are technically venomous and that the toxins differ as much as they differ from each other (and some of the 'colubrids' are actually far far more closely related to cobras than to a corn snake).

Some of these snakes are pumping out huge amounts of venom. At the end of the day are the implications in two different arenas: from the pet store perspective its pretty straightforward
1. Are all the vast majority of these snakes now considered venomous (and the Duvernoy's gland concept being dead and buried as its now been shown that its the same bloody venom gland)? Yes
2. Are all dangerously venomous? Certainly not.
3. Are there highly dangerous species lurking in there? Yes
4. Has this happened before? Yes, most acutely with the Rhabdophis in the late 70s/early 80s. It was supposed to be a psychadelic Asian garter snake, turned out to be a garter snake on crack. Highly toxic and even lethal venoms. Some of the 'colubrids' we were working with I'd considered as dangerously venomous (particularly any Psammophiinae (e.g. Psammophis and Malpolon). Even scarier, none of the existing antivenoms touch any of the colubrid venoms.

What we're after is a process of education not prohibition. I think keeping venomous should be on about the same standard as getting a motorcycle license. A reasonable baseline.

Another implication is in the area of drug design & discovery: instead of the couple hundred usual suspects being available for biomedical research, there is now about 2700!

This all made our brains hurt for a while. Your turn to feel a bit of pain ;-)

Cheers
Bryan

Simon R. Sansom · 08-31-03, 11:32 AM

Well, once the Canadian authorities get hold of that little gem we'll all be ble kiss most of our colubrids good-bye! It'll be the typical, knee-jerk, blanket legislation...

I hear the death-knell of Canadian herpetoculture.

Thanks for the ray of sunshine.

Simon

Dr. Bryan Fry · 08-31-03, 11:48 AM

Hi Simon,

I don't think it'll be as bad as all that. Yes the situation is a bit more complex but not unworkable or un-understandable. I am trying to make very clear the difference between technically venomous (pretty much all of them now) and venomous from a practical perpective (some are still to be considered utterly harmless).

Cheers
B

**Andy_G** · 08-31-03, 03:56 PM

I think Simon is right. Once they hear that snakes that were not percieved to be venomous before actually are, our stupid politcians will ban everything without thinking twice or even looking into the subject.

BoidKeeper · 08-31-03, 04:29 PM

Well we'll just have to conduct a study of our own that discredits their findings I guess. lol
Cheers,
Trevor

Lisa · 08-31-03, 06:23 PM

Actually I don't think the canadian government will notice or care. here in ontario hots are legal, and not all colubrids are dangerous.

Simon R. Sansom · 08-31-03, 07:08 PM

Hi Lisa,
Here's the thing to worry about...
Yes, hots are legal in Ontario at the Provincial level, not the municipal level (I know of precious few cities or towns where hots are allowed).
So, any snakes that you may own which were previously considered harmless but now are technically "venomous" (although actually harmless) may become by-law violations seeing as MOST municipalities ban venomous snakes.

And once the animal rights freaks get hold of that information they will finally be able to do what they've been trying to do for years - Shut us down, once and for all. These nuts never used to bother me, but now they've got a smoking gun.

And, do you think that legislators will tackle the problem sensibly?...Of course not. Like I said, we'll be looking at blanket legislation and even your corn snake may become a controlled entity.

Dr. Fry, I hope that you're right and this doesn't get out of hand, but I just have a bad feeling about this.

Cheers!

Simon

Simon R. Sansom · 08-31-03, 10:49 PM

By the way, "hello" Dr. Fry! I'd like to welcome you to the forum on behalf of all of us.

You mentioned making distinctions between dangerously venomous and essentially harmless "venomous"...While that may work in theory, it's a proven fact that when legislators hear "venomous" and "snake" in the same sentence, common sense flies out the window and madness reigns!

Simon

Dr. Bryan Fry · 08-31-03, 11:19 PM

Hi Simon

Fangs for the welcome ;-)

As for potential legislative problems, there's only one way to counteract this, and thats of course through education.

Take care
B

BoidKeeper · 09-01-03, 08:06 AM

Yes Welcome Dr. Fry. It's so nice to have a professional among us. As for the education aspect, that's where I come in. I'm a public school teacher and I do educational shows for schools in my district. It's supposed to be for the students but I try to educate my fellow educators and administrators as well.
Cheers,
Trevor

Simon R. Sansom · 09-01-03, 10:08 AM

Good for you, Trevor! I sometimes think it's more important to get through to the adults, because they're the ones who promote all the fear and prejudices.

Simon

BoidKeeper · 09-01-03, 11:10 AM

You said it! I know the kids will love it no matter what. I think that most kids who fear snakes learn it from the adults in their life. Like most behaviours they pick up, they pick them up from the adults in their lives who model behaviours for them.
Cheers,
Trevor

Lisa · 09-01-03, 03:45 PM

Quote:

Originally posted by BoidKeeper
You said it! I know the kids will love it no matter what. I think that most kids who fear snakes learn it from the adults in their life. Like most behaviours they pick up, they pick them up from the adults in their lives who model behaviours for them.
Cheers,
Trevor

You hit the nail on the head right there
My cousin is a perfect example of this. She used to play with snakes in the backyard when she was a toddler, her mom would freak out. now she's terrified of snakes. she can't even look at pics of them.

Joe · 09-01-03, 03:54 PM

thats very interesting! thanks for posting that!