Octopus Suction Cups: Everything You Need to Know

Giant octopus with suction cups or suckers on arms

Octopuses have fascinated people for centuries with their eight flexible arms covered with hundreds of suction cups. But what exactly are octopus suction cups, and how do they work?

In this guide, we’ll uncover everything you need to know about the unique suckers of octopuses. Here, you’ll learn how many suction cups octopuses have, how strong these suckers are, and more. Let’s dive in.

What Are the Suction Cups on an Octopus Called?

Suction cups or suckers of octopus close up

What we often call ‘suction cups’ on octopuses are actually called suckers. Another term used to refer to octopus suckers is ‘sucking discs.’ Scientists may also use ‘acetabula’ or ‘acetabulum,’ especially when referring to octopus suckers in a scientific context.

People may also refer to octopus suckers as adhesive discs, describing their primary function. However, the word ‘sucker’ is the most widely accepted term, as it is simple and descriptive of what it is used for.

How Many Suction Cups Does an Octopus Have?

Octopus with suction cups on tentacles

Most octopus species have two rows of suckers running down each of their eight arms. However, the exact number of suckers on an octopus varies depending on its size and species.

Smaller octopuses likely have fewer suckers per arm compared to larger species, though more scientific evidence is needed to confirm this definitively.

Take the Giant Pacific Octopus, for instance. It has approximately 280 suckers per arm, adding up to a grand total of over 2,240 suckers on its entire body. 

These many suckers are distributed across its massive frame, which can reach approximately 16 feet when fully grown.

Meanwhile, a smaller species like the Wolfi octopus, measuring less than an inch across, is unlikely to have as many suckers.

Simply put, the number of suckers on an octopus depends mainly on its species and size. If you want to learn more about different kinds of octopuses, read our comprehensive guide.

Fun Fact: Did you know that each individual sucker is controlled independently by the octopus’s brain? This allows for incredible accuracy and dexterity.

How Do Octopus Suction Cups Work?

Close up view of a common octopus

While they look like simple cups, octopus suckers are incredibly clever gripping tools that work brilliantly. To learn all about how they work, let’s first take a look at the different parts of an octopus sucker. 

Each octopus sucker has two main parts:

  • Infundibulum: The infundibulum is the outer, fleshy rim of the sucker. It’s flexible and can change shape to conform to different surfaces. When the octopus presses the sucker down, the infundibulum forms a watertight seal.
  • Acetabulum: The acetabulum is the hollow, dome-shaped center of the sucker. It contains powerful muscles that act like a tiny plunger. When these muscles contract, they pull inwards, lowering the pressure inside the acetabulum and creating a sucking effect.

Now, let’s try to break down the basic process of how an octopus sucker works:

  • Contact: The octopus presses the sucker onto an object, and the flexible infundibulum molds to the surface, creating a tight seal.
  • Suction: The muscles within the acetabulum contract, pulling the center of the sucker inwards. This creates a low-pressure area, almost like a tiny vacuum, beneath the sucker.
  • The Hold: The higher water pressure outside the sucker pushes against it, creating a strong hold.

If you want to visualize the workings of an octopus sucker, take a look at this simplified illustration.

It’s worth noting that this explanation of how octopus suckers work is simplified. In reality, scientists are still uncovering the nitty gritty details and secrets of octopus suction cups.

One interesting read I came across recently was a 2015 study titled ‘Unveiling the morphology of the acetabulum in octopus suckers and its role in attachment.’

In the study, researchers are basically investigating what makes octopus suckers work so well, particularly the suckers on Octopus vulgaris. Turns out, it’s not just suction. 

Scientists studied the bump-like structure inside the sucker, called a “protuberance,” that seems key to their amazing grip. This protuberance likely helps the sucker form a super-tight seal without the octopus needing to constantly flex its muscles. 

This saves energy and lets them stay stuck for hours. They even found tiny hairs on the protuberance, which possibly helps with the grip. 

How Do Octopuses Use Their Suction Cups?

Octopus walking using its tentacles and suckers

Octopuses use their suckers for a surprising range of tasks, going far beyond simple grabbing. Using their suckers, octopuses move, hunt, and sense the world around them. 

Let’s take a closer look at the different functions of octopus suction cups:

  • Anchoring: Suckers function as strong adhesive points, allowing octopuses to secure themselves to the seabed, rocks, corals, or even prey.
  • Movement: By strategically attaching and releasing individual suckers, octopuses can crawl, climb, and even ‘walk’ across different surfaces.
  • Prey Capture: Suckers assist in firmly grasping and controlling slippery prey such as fish or crabs. They also use their suckers to break open hard shells and other food. Speaking of food, read our guide on octopus diet to learn more about what they eat. 
  • Manipulation: The combination of flexible arms and numerous suckers allows octopuses to manipulate objects with a surprising level of dexterity. They can open containers, construct shelters, and even interact with puzzle-like objects.
  • Sensing: Octopus suckers contain specialized receptors capable of taste, smell, and touch. This provides them with valuable information about their environment.

Watch this video to learn more about the fascinating capabilities of octopus arms and their suckers:

Octopuses Can Smell, Feel, AND Think With Their Arms, Wait What?

Fun Fact: An octopus effectively has nine brains – one main brain and eight clusters of nerve cells, one on each arm, that act like mini-brains. In a way, each arm can ‘think on their own.’

This means when an octopus sucker senses something tasty, the arm starts grabbing before the main brain even gets involved. This lightning-fast reaction helps octopuses snag food in their complex environments.

How Strong Is an Octopus Sucker? 

There is no one-size-fits-all answer that perfectly quantifies how strong an octopus sucker is. Scientists use different metrics to measure the strength of octopus suckers.

Usually, they measure the negative pressure created by each sucker in relation to the surrounding environment.

Think of it this way: negative pressure describes how much of a ‘vacuum’ the octopus sucker creates. The more negative the pressure, the stronger the ‘sucking’ power.

Here are some findings from different studies that look into the strength of octopus suckers:

  • Smith (1991): A study published in the Journal of Experimental Biology recorded the strongest sucker pull at a pressure of -0.168 MPa or -24.37 psi. This means the pressure inside the sucker was way below the surrounding water pressure indicating a really strong pull.
  • Smith (1996): According to another study conducted by Andrew M. Smith about cephalopod suckers, smaller octopus suckers tend to be a bit stronger (reaching upwards of .25 MPa or 36.26 psi) than larger ones, which typically get around 0.1 MPa or 14.50 psi. Here’s a graph that shows this finding.
  • Kier and Smith (2002): This study emphasized that in shallow water, octopus suckers rarely get stronger than about 0.1 to 0.2 MPa (14.5 to 29 psi) of pressure difference (negative pressure). However, deeper in the ocean, where the ambient water pressure is higher, octopuses can produce a greater pressure difference, allowing for stronger suction.

These are the few scientific studies that directly look at the strength of octopus suckers. One key takeaway from all these is that octopus sucker strength seems to be limited by the cavitation threshold of water. 

In other words, when the pressure inside a sucker dropped low enough, the water would cavitate or form bubbles, breaking the suction. 

Simply put, measuring the strength of an octopus sucker is not that simple. It’s not as straightforward as putting a measuring instrument on an individual sucker and taking down the numbers. 

Fun Fact: According to a video from the YouTube channel Seeker, a large octopus sucker can potentially lift roughly 22 pounds of weight

Meanwhile, according to other sources, the largest suckers of a Giant Pacific Octopus can hold approximately 35 pounds each. 

What Do Octopus Suction Cups Feel Like?

If you were to touch an octopus, the main part of its suction cup or sucker would feel soft and squishy, somewhat like a mushroom. This softness is what allows the sucker to mold to surfaces and get a tight grip. 

Around the edge of the cup, you’d feel a strong ring of muscle. This muscle helps the octopus create a tight seal needed to stick to objects. You’ll feel this the most when an octopus attaches to your skin.

Inside the soft cup, there’s a slightly rough, raised area, which helps the octopus sense objects and even taste what it’s touching.

In short, imagine a combination of squishy, slightly slimy, and unexpectedly grippy material — that’s how an octopus sucker feels. 

Watch this video to get a sense of what it feels like to touch octopus suckers:

Getting Suckered By A Giant Octopus! | Big Blue Live | Earth Unplugged

Fun Fact: Did you know that octopuses are venomous? However, their venom is only administered through bites, and most kinds are not harmful to humans. In other words, touching an octopus on its suckers is safe!

Frequently Asked Questions

Octopus suction cups isolated on white background

Can You Eat Octopus Suction Cups?

Yes, octopus suction cups are edible. It’s pretty common in many cuisines to prepare octopus with the suckers intact. 

Suckers have a slightly firmer texture compared to most of the arm, but they also take on the flavor of the dish they’re cooked in.

Do Octopus Have Teeth in Their Suction Cups?

No, octopus suckers don’t have teeth. However, an octopus does have a hard, beak-like mouth for biting prey. This sharp beak is located beneath the octopus’s arms, in the very middle, where they all join together.

Do Octopus Suction Cups Hurt?

Whether or not a sucker hurts depends on the size of the octopus. Tiny octopuses have weak suckers that would feel no stronger than a little tug.

However, larger octopuses could generate enough suction to be uncomfortable or even leave a temporary mark.

So, have you learned anything about octopus suction cups or suckers? Share with us your thoughts and ideas about octopus suckers by leaving a comment below!

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