View Full Version : How does a constrictor know when to let go?
Wildside
08-13-12, 07:29 PM
I've always thought snakes were able to detect a pulse. Of course that is just the most likely rational thing I could chock it up to without ever really thinking about it. Now I am genuinely curious and interested to hear everyone's knowledge or theories.
DavethePython
08-13-12, 07:35 PM
Every time the prey ties to take a breath the snake will squeeze tighter making it harder for the prey to breathe in . Eventually they can no longer take in air and suffocate. Once the prey has completely relaxed the snake knows they are dead and let go . I am sure there is more details to it but that is the gist of it.
RandyRhoads
08-13-12, 07:36 PM
I have no idea if they can or not, but when feeding pre killed to my burm she will stay wrapped around it for sometimes 10 minutes or more and clearly it doesn't have a pulse. So my guess is that it's not a big influence on when it decides to let go.
When detecting pulses only a light pressure is used. The slight pressure lets you feel korotkoff sounds (blood rushing through a partial occluded artery). Korotkoff sounds - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Korotkoff_sounds) If you push down too much on an artery you occlude it and can no longer feel it. So my guess there is with the amount of pressure involved, no they cannot feel a pulse.
Wildside
08-13-12, 07:37 PM
Every time the prey ties to take a breath the snake will squeeze tighter making it harder for the prey to breathe in . Eventually they can no longer take in air and suffocate. Once the prey has completely relaxed the snake knows they are dead and let go . I am sure there is more details to it but that is the gist of it.
That's certainly a better theory then my half-arsed one, let's see what else is thrown out there :)
I am not sure if they CAN feel a pulse.
In my opinion, and there is NO basis for this other than my opinion,they simply squeeze and squeeze by a mental clock. Case in point - snakes that constrict F/T prey items. They definitely sense movement, which is why they don't squeeze F/T as long as live.
One thing is for sure - though the prey might suffocate, it dies from extremely high blood pressure and lack of blood flow - a much quicker demise than suffocation.
That's my "take" on the subject.
CDN_Blood
08-13-12, 07:39 PM
I would think if the prey is large enough, they could indeed detect a pulse. I mean, I've seen snakes flinch when flies land on them, so they're likely sensitive enough to feel the pulse, but it's the sustained lack of motion once prey has been dispatched that is their trigger for release. Some will wait longer than others, but if you were to ask me, I'd say that is what does it :cool:
Wildside
08-13-12, 07:42 PM
I have no idea if they can or not, but when feeding pre killed to my burm she will stay wrapped around it for sometimes 10 minutes or more and clearly it doesn't have a pulse. So my guess is that it's not a big influence on when it decides to let go.
When detecting pulses only a light pressure is used. The slight pressure lets you feel korotkoff sounds (blood rushing through a partial occluded artery). Korotkoff sounds - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Korotkoff_sounds) If you push down too much on an artery you occlude it and can no longer feel it. So my guess there is with the amount of pressure involved, no they cannot feel a pulse.
Let's not say pulse anymore then, let's just go with heartbeat in general. My curiosity has spiked from recent debating and curiosity as to why my constrictors feel the need to constrict f/t. I used to feed live. I'm ready to throw part of my original theory out the window but I wonder if the detection of a "heartbeat", say in the neck of a human, might trigger the instinct to constrict?
shaunyboy
08-13-12, 07:42 PM
as said when the snake exhales,the snake constricts tighter,so when the prey has FULLY exhaled,it CANNOT inhale,so death comes quickly
imo the snake can determine the prey,has no pulse,is limp,so is dead
cheers shaun
Let's not say pulse anymore then, let's just go with heartbeat in general. My curiosity has spiked from recent debating and curiosity as to why my constrictors feel the need to constrict f/t. I used to feed live. I'm ready to throw part of my original theory out the window but I wonder if the detection of a "heartbeat", say in the neck of a human, might trigger the instinct to constrict?
Once the snake squeezes, and the blood pressure spikes out of control, there is no longer a heart beat. The blood is not flowing, so the heart can't contract against the ventricles full of pressurized blood.
RandyRhoads
08-13-12, 07:47 PM
Once the snake squeezes, and the blood pressure spikes out of control, there is no longer a heart beat. The blood is not flowing, so the heart can't contract against the ventricles full of pressurized blood.
^^^ ..Yeah.... not sure what you mean by heartbeat rather than pulse? The electrical firing of the heart..?
^^^ ..Yeah.... not sure what you mean by heartbeat rather than pulse? The electrical firing of the heart..?
A pulse is the result of a heart beat.
RandyRhoads
08-13-12, 07:50 PM
Once the snake squeezes, and the blood pressure spikes out of control, there is no longer a heart beat. The blood is not flowing, so the heart can't contract against the ventricles full of pressurized blood.
With that being said now i'm curious what the heart does when this happens. Could it possibly send the preys heart into ventricular fibrilation, or would it just slow down into bradyastolic cardiac arrest. How would you even figure that one out, hook the prey up to a tiny EKG? LOL
Wildside
08-13-12, 07:51 PM
Heart beat and pulse are the same thing.Not exactly... If you place to fingers on your wrist or your jugular then you would be feeling pressure from the blood flow etc. If you put your hand on your chest then you would be more or less looking for vibrations from the echo.
With that being said now i'm curious what the heart does when this happens. Could it possibly send the preys heart into ventricular fibrilation, or would it just slow down into bradyastolic cardiac arrest. How would you even fifure that one out, hook the prey up to a tiny EKG? LOL
Definite Asystole. No matter how much the SA node is firing, the myocardium can't contract against blood that has no place to go.
RandyRhoads
08-13-12, 07:52 PM
A pulse is the result of a heart beat.
Well yes, but that seems very strange to wonder if the snake can actually feel a palpable heartbeat all the way inside the chest rather than pulses closer to the surface.
Not exactly... If you place to fingers on your wrist or your jugular then you would be feeling pressure from the blood flow etc. If you put your hand on your chest then you would be more or less looking for vibrations from the echo.
I corrected that statement. I am trying to type while watching t.v.
Ventricular contractions create a pulse in the distal regions of the body.
Well yes, but that seems very strange to wonder if the snake can actually feel a palpable heartbeat all the way inside the chest rather than pulses closer to the surface.
I don't believe they do. At all. I think they just squeeze until they feel no more movement and then squeeze some more.
RandyRhoads
08-13-12, 07:54 PM
Definite Asystole. No matter how much the SA node is firing, the myocardium can't contract against blood that has no place to go.
Which would eventually cause myocardial ischemia resulting in the firing of all internal pacemakers causing V Fib, correct?
Wildside
08-13-12, 07:55 PM
I don't believe they do. At all. I think they just squeeze until they feel no more movement and then squeeze some more.
I don't believe they do anymore either but for a much simpler reason. My snakes are still constricting prey that doesn't have a heartbeat.
moshirimon
08-13-12, 07:57 PM
I think certain snakes know better than others. my retic would hold the rat until it was dead. my boa will hold it for hours as if she's just making sure it will be dead
Which would eventually cause myocardial ischemia resulting in the firing of all internal pacemakers causing V Fib, correct?
I would say no... The escape rate of the AV node and Ventricles is not equal to the action potential of the myocardial cells.
VF doesn't occur from lack of heart beats, it occurs from electrical anomalies in the cells. However, those with former MIs are definitely at a higher risk for VT and VF due to the damage done to the myocardium. Whether it would be that rapid with constriction is doubtful.
RandyRhoads
08-13-12, 08:09 PM
I would say no... The escape rate of the AV node and Ventricles is not equal to the action potential of the myocardial cells.
VF doesn't occur from lack of heart beats, it occurs from electrical anomalies in the cells. However, those with former MIs are definitely at a higher risk for VT and VF due to the damage done to the myocardium. Whether it would be that rapid with constriction is doubtful.
Good to know! I was thinking as a last ditch effort to reperfuse tissue the heart would start firing any pacemaker it could. :confused:
Good to know! I was thinking as a last ditch effort to reperfuse tissue the heart would start firing any pacemaker it could. :confused:
That is a well founded suspicion, as the SA node and Ventricles definitely have their own escape rate (their own "pacemakers"). However, even they wouldn't do any good.
Nice to see you know a bit of cardiology :)
And I have to correct one statement I made up there.
EVERY movement of the heart has to do with the action potential of the myocardial cells. However, they won't start firing at VT or VF rates simply from a lack of perfusion.
Sorry about that.
RandyRhoads
08-13-12, 08:17 PM
That is a well founded suspicion, as the SA node and Ventricles definitely have their own escape rate (their own "pacemakers"). However, even they wouldn't do any good.
Nice to see you know a bit of cardiology :)
Me? Nah... I'm just a stupid redneck... lmao...
I'm stoked I could talk about this with someone with medical knowledge who knows what they're talking about! I would have been pondering on this one for a while:yes:
Me? Nah... I'm just a stupid redneck... lmao...
I'm stoked I could talk about this with someone with medical knowledge who knows what they're talking about! I would have been pondering on this one for a while:yes:
I have a way to go, yet...
Brently
08-13-12, 08:53 PM
If I was to throw my two cents out there I would say that it is an instictual response learned over millenia of ancestry. I would guess that it is a distinct feel combined with sense response from prey item and specific amounts of time of constriction. That is just my thought.
Rogue628
08-13-12, 10:29 PM
I think certain snakes know better than others. my retic would hold the rat until it was dead. my boa will hold it for hours as if she's just making sure it will be dead
I have some that do each. IMO, I think alot of it has to do with what the animal has been conditioned to eat as well. I have a few animals that I feed f/t and live to....it doesn't matter to them if it's really alive or dead, the seem to hang onto their food for about the same amount of time. (these are my king, boa, and two royals)
My two dumerils and carpet were eating live before I got them. Most of their meals are f/t now (I've fed live a couple of times waiting for a new shipment of feeders to come in) and each of them will hold onto their food for a long time as if it were live. (these are also adult animals BTW).
My burms have always eaten f/t, with an occasional live one thrown in when waiting for a new shipment to come in (I can count on one hand how many times each have taken live and still have digits left over). My bigger burm will constrict her f/t for a couple of minutes, as if to make sure it's not alive and my smaller burm will pretty much start eating off the tongs without attempting to "kill" her food most times. The couple of times I have fed her live, she held onto it for a long time, I'm assuming her way of making sure it's dead. I also had switching issues with her when she was younger and was practically hand fed for about 6 months (she's a little over a year old now).
You can take my feeding experiences and observations with my animals and apply them to the subject accordingly.
Also, has any noticed a difference in what their animals eat (f/t vs p/k or live) according to that animal's feed mode? I've noticed that my carpet's feed mode isn't what it used to be when I first got her. I'm not sure if it's because I've been feeding her better meals on a more regular basis than her previous owners, as well as feeding f/t now, so she's not quite as hungry like she once probably was. I'm not sure how relevant it would be to this thread but thought I'd throw that out there as well.
Mutimbo
08-14-12, 04:43 AM
To find out if they release when they stop feeling movement, next feeding of F/T, when you see the snake starting to relax grab and wiggle the tail of the prey item. If they begin to squeeze tighter again its probably movement. Just throwing it out there. ;)
RandyRhodes; It makes my day to know that there are rednecks in Cali! LOL
Will0W783
08-14-12, 07:18 AM
My snakes all eat f/t prey, and they all constrict it for varying lengths of time. I have some snakes that will just suck it down without ever wrapping it up and others who coil it for sometimes half an hour before eating it.
I have tried to tug or wiggle the prey and they do seem to tighten around it more, but that could just be because they don't want it taken away.
I do think that snakes instinctually sense clues about the prey's state...a struggling, panicking prey will have a pounding heart, twitch and scrabble. Once it is dead, all the muscles will relax and it will go limp. I think it is the sudden relaxation of all the muscles that the snakes sense rather than a heartbeat or pulse, as this is a very noticeable, sudden change that could be felt in all the coils as sudden loss of resistance.
However, when we condition our snakes to eat f/t prey, they instinctually know they must coil and "kill" it, but there is no signal of death...the prey never suddenly relaxes as it's already dead and limp. Without that signal, the snake doesn't instinctually know when to let go and must judge.
Just my $0.02
alessia55
08-14-12, 07:42 AM
However, when we condition our snakes to eat f/t prey, they instinctually know they must coil and "kill" it, but there is no signal of death...the prey never suddenly relaxes as it's already dead and limp. Without that signal, the snake doesn't instinctually know when to let go and must judge.
This is a good point. When you feed f/t, the snake never really sense a struggle (unless you're pulling the mouse by the tail at that point), and may still coil around it for minutes. Others somehow pick up the notion that the rat is dead, and just start eating it without ever coiling it.
DragonsEye
08-14-12, 10:32 AM
Can't remember the actual source, alas, but I have read that it has indeed been determined that prey death, as Knox mentioned, is due to the heart stopping as a result of insanely high blood pressure not to asphyxiation.
Highly unlikely that a snake is detecting heartbeats. Rather when the prey stops moving/struggling its dead and time to eat. Why would a snake bother constricting f/t prey? Simply an instinctual response.
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