Rear Fanged Colubrids....Why?

JuliusSqueezer · #1 (**permalink**) 12-25-2002, 06:23 PM

I don't know why, but late the other night while feeding my Hognosed snake...I got to wondering why an animal that feeds on such non-threatening prey such as frogs, toads, anoles etc in the wild would need rear fangs. It isn't like they use them to secure the prey or to kill them with.....Their prey is already well on it's way down the gullet before it ever gets a dose of the usually mild venom....digestion aid? In many cases I'm sure this is part of it but hardly enough reason to evolve such a thing so widespread across the globe. The one common denominator among most if not all rear fanged colubrids is that frogs and/or toads are a large part of the diet. So for now...forget the snakes and think about how frogs and toads defend themselves against predation. They have a knack for bloating themselves with air like a little balloon when something is trying to eat them. This could be a problem I guess for a slender snake to all of a sudden have it's prey bloat up while trying to swallow them...SO...I think the primary use for rear fangs is just to pop frogs and let the air out to make them easier to swallow...any thoughts on this pro or con?
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eddie · #2 (**permalink**) 12-25-2002, 06:30 PM

Sounds good in theory but I like using BFGoodrich radials for frog popping!

Possibly a combination of what you just said, to pop the food and to start the digestion process.
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JuliusSqueezer · #3 (**permalink**) 12-25-2002, 07:21 PM

The thing is Eddie....most lack any real venom anyway but have an anticoagulant and/or slightly toxic saliva...I can see where an anticoagulant might help keep a frog from resealing it's wounds by secreting whatever it is they secrete. It is also something to note that some garters, watersnakes and some others that do not have rear fangs but do have anticoagulant properties to their saliva also eat frogs on occasion. Watersnakes especially have slightly larger than normal, very sharp teeth and their bite stings a bit and bleeds profusely...I think they have the same idea as the rear fanged snakes but just need to chew a bit more. Oddly though....many of the little worm eating snakes like ringnecks have enlarged rear teeth....do adult ringnecks eat small frogs sometimes? I've never heard of one doing so but I suppose they could.
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telefrag · #4 (**permalink**) 12-26-2002, 01:16 AM

Well, actually there are a few Genus of ophistoglyphs that actually use their venom to subdue prey.

Prime examples that come to mind: Pliocercus and Boiga, which are primarily snake and lizard eaters, with some birds and rodents.
But oddly enough members of these species are also known to use constriction against their prey while the venom takes effect.

Also Trimorphodon (sp?) which are mainly lizard eaters.
Diadophis, which eat mainly snakes and snake eggs.
Clelia clelia, which is almost wholly ophiophagus.
Oxybelis, mainly a lizard and rodent eater.
Erpeton, which is known mainly to eat fish.

Its an interesting thought, but I dont think most rear fangs eat mainly anurans.
Now, in the case of Chrysopelia,Heterodon,Lioheterdon,Lystrophis, it is likely that the "fangs" do serve purpose to puncture an inflated frog or toad.
But I would guess only 40% of Ophistoglyphs make amphibians a primary portion of their diet.

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#5 (**permalink**) 12-26-2002, 05:14 AM

Great sounding reasoning Juls. That's how I understand the rear fang thing to be also.
Hey Telefrag...Could you post the common names of the species that you refer to in your posts please ? There's a TOn of us "peoples" here that get lost and haven't a clue what you are talking about specifically when you post the latin names only ya know [img]modules/Forum/images/smiles/icon_confused.gif[/img] { Yeah, myself included..UGH]. I think your posting is great, but if ya could post the common names also, maybe some of us who lack that knowledge could get to learn the latin names from reading all your posts posssibly [ Don't hold your breathe though, might take awhile hehe] [img]modules/Forum/images/smiles/icon_wink.gif[/img]
TYIA T !
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JuliusSqueezer · #6 (**permalink**) 12-26-2002, 05:15 AM

I didn't say primary. I just said "a large part of" and "most"...of course there are exceptions. But even so...Just because a snake eats mainly other snakes or rodents or birds now...doesn't mean they always have. Many factors in nature over a period of time will decide for an animal what it will and will not eat despite his specialized adaptations.

I disagree about Diadophis (ringnecks) the ones around here anyway eat mainly worms and soft insects...larger adults are known to eat small snakes lizards and of course FROGS! I just looked that up...I trip over them daily walking out my door. I have never seen them eat anything around here but worms and grubs. As a kid, I used to keep them and flathead snakes (wormsnakes) together sometimes 10-12 per cage...I never had one eat a cage mate though so the fact that they are ophiophagus is all new to me.

Oxybelis eat frogs too...and hummingbirds of all things. How much meat could possibly be on a humming bird?

Erpeton...I know nothing really about them...everything I read says "mainly fish" but what lives in ponds and eats fish, usually eats frogs too at least on occasion but geeez...you gotta pull out such a freaking oddball? This snake just barely even gets to count as a snake.

My guess is that your 40 Percent stat is way way off. You managed to dig up a few oddballs that don't "Mainly" eat frogs/toads....but all but one or two do at least in part....besides that...don't you know that 75% of all statistics are wrong? hehe including this one!
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JuliusSqueezer · #7 (**permalink**) 12-26-2002, 05:26 AM

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE> Hey Telefrag...Could you post the common names of the species that you refer to in your posts please ? </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

Trimorphodon = Lyre snakes
Diadophis= ringnecks
Oxybelis= green vinesnakes (south american not asian) I actually had a photo of one of these eating a frog somewhere...I think it's upstairs on the other computer.
Erpeton= Tentacled Snake
clelia...i forget the name...starts with an M...looks kinda like a queensnake cept prettier. Massurana or something(sp???)

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#8 (**permalink**) 12-26-2002, 05:44 AM

Thanx Juls ! [img]modules/Forum/images/smiles/icon_wink.gif[/img] Just trying to learn off of you that are more "versed/edshumacteed" than I in relation to this stuff [img]modules/Forum/images/smiles/icon_biggrin.gif[/img]
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#9 (**permalink**) 12-26-2002, 03:40 PM

If you learn something for yourself, you tend to retain it longer than if someone just feeds you the answers. Besides, unless the common names are agreed on worldwide, they're not a very effective tool for communication.
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#10 (**permalink**) 01-02-2003, 10:48 AM

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>If you learn something for yourself, you tend to retain it longer than if someone just feeds you the answers. </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

J..Some of us trust "other" members answers here more so than we would a google search engine actually [img]modules/Forum/images/smiles/icon_biggrin.gif[/img] We all have different venues for learning as well. Not to mention that most of our members would have no clue what a latin name is refering to actually.

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>unless the common names are agreed on worldwide, they're not a very effective tool for communication. </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

If such were to be the case.. I am sure that with the great member basing we have here at RTB, that such would quickly be noted by at least one person
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NOT all of us have learned what we have retained from reading a book or a search engine result even.....Some of us pick up what we don't learn hands on by way of asking others that do know what we seek to learn. [img]modules/Forum/images/smiles/icon_eek.gif[/img]
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bensnacks · #11 (**permalink**) 01-02-2003, 12:55 PM

Bioga irreguleris(Brown Tree snake )
Dendrelaphis punculata &D. calligastra (Common & northern tree snake)
Mainly a frog eaters ,although also notorious for eating birds,
also use constriction.
Maybe the mild venom is an evolutionary left over from when
eating habits required a more potent venom.Lack of need watered it down.

Just a stab in the dark. [img]modules/Forum/images/smiles/icon_wink.gif[/img]

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bensnacks · #12 (**permalink**) 01-02-2003, 01:20 PM

Also worth mentioning B. irregularis(Brown tree snake)
was introduced to the Pacific island of Guam ,from Aust.,during WW2.
Has since wiped out most of the indigenous bird population and has also
become quite a bit larger and significantly more potent with ,I belive, one death
recorded due to a bite!?

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JuliusSqueezer · #13 (**permalink**) 01-02-2003, 04:10 PM

Yah, they have also caused quite a few house fires from crawling into substandard archaic power transformers. These snakes have become quite a pest as there is no natural predator to keep them in check there and they have a year around supply of lizard feeders so their population is unreasonable. The Island of Guam is literally crawling with them.....something like 2000+ snakes per square mile is an estimate. I don't blame Hawaii for not wanting any there. Hawaii has too many endangered bird species hanging by a delicate thread as it is.

And yah...some rear fanged snakes pack quite a punch if they happen to get a hold of you...just most do not seem to have an interest in biting. Boomslangs, Brazilian Smoothsnakes (aka false water cobras, mangrove snakes and quite a few others can put a hurt on you...especially the boomslang ....a boomslang though doesn't have the same rearfang setup as say...a hognose snake...their fangs are more developed and look much like elapid fangs except that they are set further back in the mouth. They open wide and use their's for defense and are more capable of popping you with them. And because they are arboreal, live in dense jungle and are well hidden in the bramble bushes...someone encountering them usually ends up walking into one face first. Not a pleasant way to start the day.
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#14 (**permalink**) 01-02-2003, 04:13 PM

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE> Not to mention that most of our members would have no clue what a latin name is refering to actually. </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>unless the common names are agreed on worldwide, they're not a very effective tool for communication. </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

If such were to be the case.. I am sure that with the great member basing we have here at RTB, that such would quickly be noted by at least one person
[img]modules/Forum/images/smiles/icon_wink.gif[/img]

That's kind of directly contradictory to what you just posted, don't ya think? If you don't know the latin name, there are several species that share the same common name. If, as you say, tons of our users "wouldn't have a clue" about latin names, what makes you think they'd have a clue which common name is actually referring to which species? See where Julius added after Green Vines snakes (south american, not asian)? If you know the latin names, then it's not necessary and there's no confusion.
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#15 (**permalink**) 01-03-2003, 06:11 PM

Nobody mentioned Dispholidus typus, they don't mainly eat frogs... [img]modules/Forum/images/smiles/icon_wink.gif[/img]
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telefrag · #16 (**permalink**) 01-03-2003, 06:26 PM

Hey Lori,
the reason I dont post common names is simple.

I dont KNOW them, I have always thought it a useless endeavor to learn the common names, because they dont help you with identification, especially if you deal with Foreign dealers,importers, and scientists.
While a great many users dont use latin names, I would have to say at least 90% of my herping "buddies" do.
Some people dont need to know them, thats true. For me its necessary.
a lot of times many species do not even have common name.

Perhaps when a latin name is posted, its a good idea for the reader to take it upon themselves and figure out what it is (uhem google!), that just helps the learning process for those who wish to expand their herpetocultural mojo. [img]modules/Forum/images/smiles/icon_biggrin.gif[/img]

Oh BTW, Julius, Erpetons are very much snakes, albiet strange,
they are still snakes down to the core.
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telefrag · #17 (**permalink**) 01-03-2003, 06:34 PM

>>I didn't say primary. I just said "a large part of" and "most"...of course there are exceptions. >>

From your first post:
The one common denominator among most if not all rear fanged colubrids is that frogs and/or toads are a large part of the diet. So for now...forget the snakes and think about how frogs and toads defend themselves against predation.

>>Erpeton...I know nothing really about them...everything I read says "mainly fish" but what lives in ponds and eats fish, usually eats frogs too at least on occasion but geeez...you gotta pull out such a freaking oddball? This snake just barely even gets to count as a snake.
>>
these just happen to be my primary focus ATM, I really doubt they can eat frogs.
(that just goes from watching their feeding habits)

>>My guess is that your 40 Percent stat is way way off. You managed to dig up a few oddballs that don't "Mainly" eat frogs/toads....but all but one or two do at least in part....besides that...don't you know that 75% of all statistics are wrong? hehe including this one!

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JuliusSqueezer · #18 (**permalink**) 01-04-2003, 09:10 AM

"a large part of" does not mean primary. A large part of my diet is Quesadillas...but it's not even close to my primary intake of food. To make this even more relevant...from time to time, I like to eat kabobs...so I have skewers handy for when I do...However I only probably actually use them twice a year...but when I do, I have the tools [img]modules/Forum/images/smiles/icon_smile.gif[/img] Why couldnt an erpeton eat a frog? if it can eat a fish, it can eat an occasional small frog? They do come in all sizes. Again though...even though a snake's primary diet may be something else...who's to say what it was or wasn't a million years ago? Unfortunatly, snake fossils are very rare and I suppose snakey coprolite (fossil dung) is even more rare...but still..You brought up a few that probably dont eat many..one or two that may not eat any....but still may at times for all we know...I was hoping the part about "of course there are exceptions" would have been enough to save us all the digging up of oddball snakes....

but anyway fragman...So, you diagree that rear fanged/enlarged rear teeth evolution had anything to do with consumption of amphibian prey?

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE> a lot of times many species do not even have common name.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE> really? I was unaware of this. I bet, unless they are on some remote island that has just been discovered, someone, somewhere has a common name for them.
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#19 (**permalink**) 01-05-2003, 05:57 AM

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>a lot of times many species do not even have common name.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

Which ones are examples of ones that don't have a common name even ?
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bensnacks · #20 (**permalink**) 01-05-2003, 12:01 PM

Ummm......Jules???
You may consider us ,Australia ,( ...you know,
that big sub-continent below the equator) to be
a remote island that has just been discovered.
None the less we have at least 30 amphibian species
and 60 other species not identified under a common name.
That being said I would like Tele. to state both.
Novice's like me can still learn by that. [img]modules/Forum/images/smiles/icon_wink.gif[/img]
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