How snakes know to stop constricting

[Iflln2fntsy]

The researchers didn't use corn snakes, but I am guessing they use similar cues to know when to stop constricting.

"Snake modulates constriction in response to prey’s heartbeat
Boback et al.
Abstract:
Many species of snakes use constriction—the act of
applying pressure via loops of their trunk—to
subdue and kill their prey. Constriction is costly
and snakes must therefore constrict their prey
just long enough to ensure death. However, it
remains unknown how snakes determine when
their prey is dead. Here, we demonstrate that
boas (Boa constrictor) have the remarkable ability
to detect a heartbeat in their prey and, based on
this signal, modify the pressure and duration of
constriction accordingly. We monitored pressure
generated by snakes as they struck and constricted
warm cadaveric rats instrumented with a simulated
heart. Snakes responded to the beating
heart by constricting longer and with greater
total pressure than when constricting rats with no
heartbeat. When the heart was stopped midway
through the constriction, snakes abandoned
constriction shortly after the heartbeat ceased.
Furthermore, snakes naive to live prey also
responded to the simulated heart, suggesting that
this behaviour is at least partly innate. These
results are an example of how snakes integrate
physiological cues from their prey to modulate a
complex and ancient behavioural pattern."
http://rsbl.royalsocietypublishing.org/content/early/2012/01/11/rsbl.2011.1105

 

[Karoni]

That is so totally amazing.

 

[HazAnga]

That's cool, I never even thought of that... I just figured it was triggered by when the pray stops moving...

 

[knox]

In recent years, it has also been discovered that prey doesn't die from suffocation, but rather extremely high blood pressure from the constriction.

True, it may be impossible for the prey to breathe, but it's Cardiac Failure from High Blood Pressure that does the most damage.

 

[Michael823]

Interesting... but sometimes I think science over-thinks experiments on animals. So many "experiments" just seem to determine routine behavior that most pet owners notice on their own (if they're observant).

A false heart in a cadaver of a prey item is an interesting test, but without a snake having any knowledge of what a heart-beat really is, it seems more likely that it's just the general movement (which comes as what the scientists have labeled a "heart") that they detect. A good experiment to test against their theory, would be to put a vibrating mechanism in the prey's head (or another obscure location other than the heart) to prove whether it's a distinct 'heart-beat' that they detect. I think the snake would show the same response to the prey, regardless of location, and regardless of whether the movement patterned a heart, a constant vibration, or a tug.

I know from my experience of feeding snakes, and having been bitten feeding them (god knows how many times), it seems mostly like movement in general causes them to constrict/not. Whether it was letting my hand go limp to let a snake release it's accidental grip, or tugging a little bit on a mouse that's been bitten, just to get the snake a little more eager to eat, I've just naturally come to the conclusion. And it really makes the most sense, in my opinion.

Interesting test, though! There are a lot of mysteries of animal behavior that people haven't even begun to scratch the surface of understanding, and very sadly it's disappearing even quicker than we're understanding. At least people are still out there trying to.

 

[lovehatepassion]

several of my snakes constrict for 5 to 10 minutes even though i feed them all frozen thawed. their prey certainly doesnt move or have a heartbeat. they still feel they need to 'kill' it