Research Reveals How Boa Constrictors Breathe While Crushing Prey!

Written by Jude Speegle
Published: April 22, 2022
Image Credit Jan Hejda/Shutterstock.com
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Think You Know Snakes?

Boa constrictors are possibly a young child’s worst nightmare once they learn about them. A snake with the ability to wrap itself around something or someone and never let go, not until death… that’s scary! But how does a boa constrictor breathe while crushing prey?

Having a boa constrictor as a pet is not unheard of, but they need to be taken care of in unique ways. The wrong move could cause your boa constrictor to feel threatened and try to wrap around you. Some types can also grow up to ten feet, so they aren’t a pet for everyone.

In the wild, the boa constrictor seeks out its prey and then wraps its body around them, squeezing tighter and tighter with tremendous force until its prey can’t breathe or dies. Their diets consist of smaller animals like rodents and birds, though they can also eat pigs and deer.

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Think You Can?

The mystery here is apparent: how can this creature constrict tight enough to kill other animals without killing itself? Let’s find out!

How Constriction Works Within the Boa

Boa Constrictors Breathe While Crushing Prey
Boa constrictors kill by cutting off blood flow, not by suffocation.

Natalia Kuzmina/Shutterstock.com

First, let’s dig in with how exactly a boa constrictor managers to kill its prey, as most snakes kill them with venom injected when they bite into them.

Boa constrictors pursue their prey the same way as other snakes. They hide in the brush or trees and wait until some unsuspecting animal crosses their path, then strike. Instead of sinking their fangs into their flesh, boas constrict themselves around their prey with their long, slinking bodies.

It is commonly thought that boas suffocate their prey to death, but that isn’t the case. When this snake traps a rodent or bird, they tighten themselves around them and kill them by cutting off their blood circulation.

They can do this because their muscles are exceptionally strong. They can bite down on the animal they’ve caught and then quickly coil around it and hold it into place, tighter and tighter. 

Boa constrictors are so strong that they don’t even kill by suffocation, as their method of killing is more quick and efficient. Blood circulation stops, and they die as a result, not even feeling too much pain.

The blood in all living things has oxygen in it. This means that if they were dying of not being able to get air, they would live longer thanks to the little bit of oxygen in the blood. Keeping the blood from circulating affects the heart and ultimately kills the animal first.

How Do Boa Constrictors Breathe While Crushing Prey?

Boa Constrictors Breathe While Crushing Prey
Boa constrictors breathe by changing what parts of their ribs are flexing while they crush their prey.

Jan Hejda/Shutterstock.com

For the longest time, it was just a mystery as to how boa constrictors managed to breathe while crushing their prey. Their muscles would slowly constrict and crush, and we just understood that somehow it didn’t affect them.

A recent study in the Journal of Experimental Biology finally found the answer to this age-old question. Researchers used a simple old blood pressure cuff and some electrodes to discover how boa constrictors breathe while constricting.

Snakes aren’t like humans or mammals in general; they don’t have individual diaphragms. This means that the movement of their ribs is what helps them to breathe. When it comes to the boa constrictor, they are apparently able to change what individual rib sections they use to breathe.

Scientists theorize that the reason they can do this goes far back into their evolution, and it’s why they ended up evolving to constrict their prey. If they are using the muscles closest to their head to squeeze, their lungs push alone from the back end and up to the front of their lungs.

Muscles Like an Accordion- How Boas Breathe

Boa Constrictors Breathe While Crushing Prey
Boa constrictors use their muscles like an accordion, expanding and contracting their ribs to breathe.

reptiles4all/Shutterstock.com

Normally, boas breathe by compressing and expanding their muscles and ribs to draw breath in and out. It is similar to the movement of an accordion. Their heart is closer to their head, so they breathe mainly from that direction, but it’s possible to breathe with their back ends as well.

This was all figured out in such a simple manner. Scientists noticed that these snakes were contorting themselves in different manners when constricting prey and thought they were potentially breathing from other spots. This was apparent when compared to how they breathed at rest.

Snakes have extraordinarily long lungs that spread down throughout their body, so it was indeed a mystery how they retained the capacity to breathe. The experiment used blood pressure cuffs on different points of a snake’s length, tightening around them until they couldn’t breathe in that position. This was done to imitate what occurs when a boa is wrapped around its prey.

Causing the boa constrictor to use different areas for breathing, the scientists were able to observe. They recorded the extent of their ability to breathe regardless of whether their ribs were too compressed.

Studying the Breathing Boa While Constricting

Boa Constrictors Breathe While Crushing Prey
Once a boa constricts, it turns out that the muscles for the ribs at the front of the snake don’t work at all when it comes to breathing.

Sanne Romijn Fotografie/Shutterstock.com

Scientists also took x-rays of the snakes to see how their ribs did move while they were breathing. They placed electrodes along the snake’s muscles to record any nerve stimulation. Another tactic they used was to recreate a computer model of the boa constrictor’s ribs and vertebrae to test whether they could recreate what they saw in the x-rays. 

Once a boa constricts, it turns out that the muscles for the ribs at the front of the snake don’t work at all when it comes to breathing. The boa initiates the muscles at the back end of its body. They can swap back and forth between the parts of their body, which is fascinating. 

The muscles at the back end of the snake push the air up through the constricted part so the snake can breathe fully even when tightened completely around its prey. Fascinating, isn’t it, that the snake evolved the way it did just because of how it breathes?

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About the Author

Jude is a writer both by trade and by heart. They have been writing since a very young age and have eight years of professional writing experience. Passionate about animals, Jude has three birds and three cats.