how many pounds of pressure can a python exert?
Questions About Snakes

How Tight Can a Python Squeeze?

Pythons are constrictor snakes found in the wilds of Asia, Africa, and Australia. They kill their prey by squeezing it to death using their powerful coils. There are many species of pythons, including reticulated pythons, Burmese pythons, and ball pythons.

How tight a python can squeeze depends on how thick its body is. The larger the snake, the more muscle mass it has, and the tighter it can squeeze. Reticulated pythons can exert 7.8 pounds of pressure per square inch (PSI). Burmese pythons clock in at 6.23 PSI, and ball pythons can manage 4.0 PSI. But all pythons can vary the pressure they exert, depending on the size of their prey.

Constriction uses a lot of energy, and the snake will only expend as much as is necessary. Pythons can detect their prey’s heartbeat, and they stop squeezing when they know their victim is dead. Large species of pythons can easily squeeze hard enough to kill a fully-grown human.

Do All Snakes Constrict Their Prey?

Constriction is a common method that snakes use to subdue and kill their prey. The majority of snake species are non-venomous constrictors. Only around 600 of over 3,500 known snakes are venomous.

Unlike venomous snakes, constrictors can’t poison their prey. Instead, they catch their prey in their small hooked teeth, and curl their body tightly around it. The animal soon dies, and the snake then swallows it whole.

Even small species, like corn snakes, kill by constriction. However, they’re not very strong. Small constrictor snakes can only handle animals such as mice and songbirds.

Pythons, however, are some of the most powerful constrictors in the world. There are many species in the python family, including ball pythons, which make popular pets. Reticulated pythons and Burmese pythons are two of the biggest extant species of snake (alongside green anacondas). Adults of these species can easily kill huge animals such as pigs and deer.

Pythons and other constrictors will only squeeze an animal to death if they intend on eating it. Constriction takes up a lot of the snake’s energy, so they only do it when necessary. They won’t attack an animal that’s too big for them to swallow.

How Do Constrictor Snakes Kill?

The constriction method is used by both active hunters and ambush predators. Active hunters, like king snakes, chase down their prey. Ambush predators, such as ball pythons, lie in wait for prey to pass by. This is how constriction works:

  1. The snake strikes at the prey and grabs it in its hooked teeth.
  2. Immediately, the constrictor snake will wrap its victim several times in its coils. This holds the animal still, so it can’t escape.
  3. The snake holds its prey’s head in its jaws. This stops the animal from being able to fight back.
  4. The snake then starts to squeeze the animal more and more tightly. Within seconds, the animal falls unconscious.
  5. After several minutes, the prey’s heart stops, and it dies.
  6. Once the animal is dead, the snake then swallows it whole, starting with the head.

The constriction method is only effective when used on endothermic (warm-blooded) animals, like rodents and birds. It seems to have little effect on ectothermic (cold-blooded) animals, such as lizards and frogs.

According to National Geographic, researchers once observed a boa constrictor squeezing an iguana for an hour. The next day, the iguana was found alive and seemingly unharmed. This is why snakes such as hognose snakes, that primarily hunt reptiles and amphibians, don’t use constriction. Instead, they swallow their prey alive.

strongest snake squeeze

Do Pythons Suffocate Their Prey?

Pythons and other constrictor snakes were once thought to kill through asphyxiation. Scientists assumed that constriction worked by squeezing the air out of the animal’s lungs, essentially suffocating it. It was said that the snake would squeeze more tightly when the animal exhaled, preventing it from taking a breath.

We now know, however, that this theory isn’t true. A study in the Journal of Experimental Biology found that constriction has nothing to do with suffocation. Instead, the act of constriction triggers cardiac arrest, by affecting the prey animal’s blood circulation.

Within a few seconds of being constricted, the animal’s blood pressure begins to drop. This quickly results in bradycardia (a dangerously slow heart rate). Eventually, the circulatory system can’t function as normal. Tissue damage and neural damage swiftly ensues. The heart then stops completely.

To achieve this, a python has to compress the animal strongly enough to interfere with its blood pressure. But what’s more important is the duration of the constriction. The snake must continue squeezing until the animal is dead, for as long as that may take.

How Do Pythons Know When to Stop Squeezing?

It would be dangerous for a python, or any other constrictor snake, to let go of their prey before it’s dead. This is for two main reasons:

  • Letting go of an animal while it’s still alive means that it may have a chance to escape
  • Swallowing a live bird or mammal could result in internal tissue damage. If the animal regains consciousness, it could attack the snake from the inside

However, this rarely happens because constrictor snakes, like pythons, can tell when their prey is dead. According to Biology Letters, constrictors can sense their prey’s pulse. They only stop squeezing once their victim’s heart is no longer beating.

This is an innate ability that constrictor snakes are born with. Even a captive-bred python, who has never eaten live prey, would know how to do this.

The only instance in which a python might let go prematurely is if the prey animal attacks it. This can happen if the snake misjudges the strike, and grabs the animal’s rear instead of its head.

Pet snake owners sometimes witness this when live-feeding. Occasionally, a mouse or rat will manage to bite the snake while wrapped up in its coils. This sometimes prompts the snake to let go.

How Tight Can a Python Squeeze?

How tight a python can squeeze depends on its size. In particular, it appears to be determined by the diameter (width) of the snake’s body. A thicker snake has more muscle mass than a thinner snake. It is therefore stronger, and can squeeze harder.

A study in the Journal of Experimental Zoology examined which factors could affect constriction performance in ball pythons. The researchers found that constriction strength isn’t affected by how much experience the snake has. In other words, pythons don’t ‘get better’ at constriction with practice.

The only thing that has an effect is the snake’s diameter. Male and female pythons of the same size are equally as strong. However, as female pythons grow larger than males, adult females are typically stronger than males.

Interestingly, it seems that constrictor snakes don’t always squeeze their prey as hard as they can. They can choose how much or little pressure to exert. This will vary depending on how large the prey animal is, and its heart rate.

To measure how tight a snake can squeeze, scientists use a metric called pound-force per square inch (PSI). This refers to the pounds of pressure that snakes can exert upon one inch of their prey’s body.

Although there are over 40 species of python, only four have ever been studied in this way. They are the reticulated python, the Burmese python, the ball python and the African rock python.

How Strong Is a Reticulated Python?

Reticulated pythons (retics) are one of the largest snake species in the world. Retics can reach over 26 feet long. The largest reported specimen was 33 feet, though this wasn’t proven.

A study in the Journal of Experimental Biology measured the constriction pressure of 48 reticulated pythons. The maximum pressure recorded by a reticulated python in the study was 7.8 PSI. This means it exerted almost 8 pounds of pressure onto every square inch of its prey’s body.

The researchers found a correlation between the snake’s size and its strength. The larger reticulated pythons squeezed significantly harder than the smaller specimens. Also, the more coils a snake wrapped around its prey, the higher the constriction pressure.

Wild reticulated pythons are strong enough to kill and eat deer, wild pigs, and large primates. They’re also the only snake that’s ever been proven to hunt fully grown humans.

How Strong Is a Burmese Python?

Burmese pythons almost match reticulated pythons in terms of size. They can reach over 23 feet long, and the minimum adult length is 7.7 feet. A fully grown Burmese python can weigh over 400lbs.

The researchers who studied reticulated pythons also tested the strength of 17 Burmese pythons. The maximum pressure exerted was 6.23 PSI, so slightly lower than the retics. Again, the researchers found that larger snakes squeezed more tightly than smaller snakes.

It’s likely that Burmese pythons had a lower average PSI than retics because of a size disparity. The biggest Burmese python in the study was 12 feet long, whereas the largest reticulated python was 18 feet.

Wild Burmese pythons can subdue prey as large as pigs and goats. In Florida, where they are an invasive species, they’ve been known to eat alligators.

How Strong Is a Burmese Python?

How Strong Is an African Rock Python?

African rock pythons (Python sebae) are native to sub-Saharan Africa. They are one of the largest pythons: some adults may exceed 20 feet in length. This means that they can rival Burmese pythons, but don’t grow quite as large as retics.

A study in Biology of the Boas and Pythons tested the strength of African rock pythons. The snake that they studied measured around 6 feet long – a particularly small specimen. It exerted a peak pressure of 25 PSI.

This is a tighter squeeze than any other python that has been measured so far. However, it was not a large study, and only one specimen was examined. Much more research is necessary before we can draw any conclusions.

How Strong Is a Ball Python?

Ball pythons are relatively small snakes, compared to most others in the Python genus. The maximum length of a female ball python is 6 feet, whereas males only typically reach 2-3. This means that they have thinner bodies and less constricting power than reticulated, Burmese, or African rock pythons.

The same study that examined an African rock python also tested 3 ball pythons. The maximum squeeze strength observed was approximately 4 PSI. Wild ball pythons hunt small animals like shrews, mice, and rats. So, they don’t need to be as strong as the larger species.

It’s a small sample size, so we can’t generalise this to all ball pythons. But we do know that the larger a ball python is, the harder it will squeeze.

Which Snake Is the Strongest in the World?

The aforementioned Biology of the Boas and Pythons study measured the strength of 12 different constrictor snakes. This included boas, pythons, and colubrids (e.g. corn snakes and gopher snakes).

They measured each snake’s length, and the diameter of each snake’s trunk, in the region used for coiling. They then tested how tight each snake could squeeze its prey.

What they found was a significant correlation between the snake’s diameter, and the amount of pressure exerted. The thicker the snake, the harder it could squeeze. As the snake’s diameter doubled, the constriction pressure was 2.6 times stronger.

But the snake’s species also has an effect on its strength. Comparing snakes of the same size, pythons and boas generally squeezed harder than colubrids.

Based on this, the strongest snake in the world is probably the green anaconda (a type of boa). These huge snakes can reach upwards of 29 feet in length. A study of one gigantic specimen recorded a maximum PSI of 90.

However, it’s possible that a reticulated python of the same length could exert a similar amount of pressure. Thus far, only smaller specimens have been studied, so more research needs to be done.

The strongest colubrid is likely to be the kingsnake (Lampropeltis sp). These snakes hunt other snakes, and can kill snakes up to 20% larger than themselves. They average 4 to 5 feet in length, but can exert pressures of 3.5 PSI. This makes them on par with pythons of a similar size.

Can a Python Squeeze a Human to Death?

There is only one reason that a python would ever constrict a human: hunger. When hungry, snakes will hunt any animal they can find of an appropriate size. If a snake perceived a human as a viable meal choice, they may attack.

Fortunately, there are very few species of snake large enough to eat humans. Snakes can’t bite their prey into pieces, so they wouldn’t waste time killing an animal that’s too large. A snake would only attempt to kill a human if it was sure it could swallow it.

It’s theoretically possible for any large python to squeeze a human to death. However, the only species that has been proven to hunt and eat humans is the reticulated python.

This mostly happens in hunter-gatherer and farming communities. Most incidents have occurred in the Philippines and Indonesia. There have also been reports of green anacondas eating humans, though none have ever been confirmed.

Can Pet Pythons Kill You?

Pet pythons occasionally constrict their owner’s hands and arms. This can sometimes happen if the snake is hungry. The snake isn’t trying to kill its owner – it’s merely mistaken them for food.

Captive snakes can develop a “feeding response” when their enclosure is opened. This means they may strike at anything that comes in, including their owner’s hand. This is unlikely to cause any damage other than a small wound.

But larger species of python, once they reach adulthood, can be a danger to their owners. Although incidents are rare, they are not unheard of. According to BBC News, a 31-year-old man was killed by his African rock python in 2018.

There have also been reported incidents of pet pythons killing children. The Humane Society has several examples, including a 2-year-old girl who was killed by a Burmese python.

How Do You Stop a Snake from Constricting?

You may wonder what to do if you find yourself being squeezed by a python, or other constrictors. There are a few different methods you can use to stop a snake from constricting.

Start by unwrapping the snake from your body, beginning with its tail. Grasp the tail gently but firmly, and unwind the snake’s coils one by one. When you get to the head, hold it gently and unhook its teeth.

If the snake still refuses to let go, spray some alcohol into its mouth. For example, you can use pure vodka, hand sanitizer, or rubbing alcohol. It has a bitter taste that is unpleasant to snakes, so the snake is likely to let go. For more information, see how to get a snake to stop constricting.