![boa vs python squeeze boa vs python squeeze](https://www.snakesforpets.com/wp-content/uploads/2018/10/Difference-Between-a-Python-and-Boa-Constrictor-e1589267055571.jpg)
They use their flicking tongue to pick up the scent. They ambush their prey, which means that they will hide and wait for something yummy to go by and then do a surprise attack. So today the rule is: keep squeezing for N seconds after each heartbeat, for some fairly small value of N.Boa Constrictors are one of the largest snakes in the world, along with theīoas are non-poisonous but just as deadly. Eventually this struggle detection became sensitive enough to detect individual heartbeats. In fact one can concoct a just-so story that starts from a primordial behavior of squeezing for a fixed interval, which then became modified by selection to restart the interval timer each time the prey kicks or struggles. They squeeze until the heart stops, which presumably happens much sooner in warm-blooded prey. But it doesn’t follow that they’re wasting energy by over-squeezing warm-blooded prey. Their answer, as you say, is that not all prey is warm-blooded. Rather, the authors merely wonder why the snake detects heartbeat at all, given that warm-blooded prey could be reliably killed simply by squeezing for a short, fixed interval. That would imply that the prey’s heart keeps beating long after it’s dead. Biology Letters online, doi: 10.1098/rsbl.2011.1105Īs I read it, the paper doesn’t say that the snakes squeeze warm-blooded prey longer than they need to. Snake modulates construction in response to prey’s heartbeat. I have no idea what kinds of prey predominate in a modern boa’s diet.īoback, S. This explanation is interesting, but if boas’ current prey are mostly endothermic, there should have been selection to eliminate the heartbeat cue. Why the extra time and heartbeat monitoring? The authors theorize that the heartbeat monitoring originally evolved when the snakes preyed on cold-blooded (“ectothermic”) animals like lizards, which can live a lot longer than a few minutes without respiration and movement, and so cessation of heartbeat was a more reliable cue to death. The authors raise one caveat: warm-blooded (“endothermic”) prey like birds and mammals are killed much more quickly than 20 minutes, and snakes could use the cessation of movement as a cue, saving them lots of squeezing time. Regardless, this is the first demonstration that snakes can detect and monitor the heartbeat of prey that they’re squeezing. But snakes also apparently learn to squeeze less when the heart stops, too. Is this learned or innate? Experiments with naive boas, who had never squeezed a live prey, suggest there’s at least a strong innate component, i.e., an evolved, genetically-based ability to stop squeezing when you detect a stopped heart.
#Boa vs python squeeze full
Top: full 20-minute heartbeat Middle: no heartbeat from outset Bottom: heartbeat discontinued after 10 minutes. Snake pressure (vertical axis) versus time of squeezing prey (horizontal axis).
![boa vs python squeeze boa vs python squeeze](https://snake-facts.weebly.com/uploads/6/5/5/3/6553869/reticulated-python.jpg)
Well, the experiment is gruesome, and personally I wouldn’t kill rats to answer this question, but Boback et al. (access is free), is that the snake monitor’s the prey’s heartbeat, and stops squeezing when the heart stops beating.
![boa vs python squeeze boa vs python squeeze](https://d3i71xaburhd42.cloudfront.net/e47212714c8e45e4dcc6720407fb71e97be2645d/2-Figure1-1.png)
The answer, which might seem obvious but is still cool, is in a new paper in Biology Letters by Scott Boback et al. Many of you might have said, “When the breathing stops,” but that’s apparently not correct. It takes a lot of energy for a cold-blooded (ectothermic) reptile to squeeze that hard (its metabolism goes up sevenfold when squeezing), and during the act the snake itself could be subject to predation.You don’t want to squeeze longer than you have to, but how do you know your prey is dead? Squeezing prey in this way is costly for the snake.