Common octopus closeup of head and eyes with texture and yellow red skin colour

Outstanding facts about octopuses (not octopi)

2 minute read

Octopuses are amazing. Here are some fascinating facts you may not know about these remarkable octopedal creatures.

Before you continue!

All marine wildlife is facing increasingly difficult challenges caused by pollution, overfishing, and climate change. Octopuses are no exception.

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A curled octopus  |  Image credit: Billy Arthur

It’s not octopi

Did you notice the word octopuses in the title and cringe at our error? Actually, octopi is not the plural of octopus as is generally thought.

The error comes from the assumption that 'octopus' is a Latin word when it is in fact Greek. The true plural would be 'octopodes' but it has been accepted that 'octopuses' is the correct plural in the English language.

They can be bigger than a bus

The biggest giant Pacific octopus ever recorded reached a weight of 600 pounds. That’s nearly four times the weight of the average person. This huge octopus was also 30ft across – longer than a London bus.

The smallest type of octopus discovered is called an octopus wolfi, weighing only a gram and can also be found in the Pacific but in shallower waters.

Common octopus underwater partially hidden amongst kelp. In this case its skin is a mottled grey/cream.

A common octopus  |  Image credit: Jon Bunker

They can walk on land

Octopuses can use their tentacles to walk along the beach if they are trapped in a low tide or hunting for prey among the rock pools. After eating all the prey in one pool, they can pull themselves out of the water to go and find the next place to hunt.

If you see an octopus walking on land, make sure you give it plenty of space so you don’t frighten it. If you think something may be wrong, contact the British Divers Marine Life Rescue. Never attempt to put any marine animal back in the ocean without help or advice from the experts, as it may be sick or injured.

They are colour blind

Watching octopuses effortlessly change colour to match their surroundings is truly mesmerising. Their ability to do this is all the more remarkable when you realise that, unlike humans, octopuses are unable to distinguish colour using their eyesight. This suggests that they are likely to be colour blind. Yet they are also some of the fastest colour-changers in the animal kingdom and can alter their appearance faster than we blink. So, how do they do it?

A close up of an octopus eye

A close up of an octopus eye  |  Image credit: Oleksandr Sushko

The secret lies in specialised cells found in their skin called ‘chromatophores’. Altering the shape and size of these colour-changing cells allows octopuses to be camouflaged from potential prey and predators. It remains a mystery how they know which colour to become so as to blend in with their environment. Some theories suggest that octopuses can see patterns of light waves, while others suggest they detect changes in brightness and contrast. Whatever the reason, this remarkable adaptation highlights their unique ability to survive and thrive in diverse marine environments.

A close up of a painted goby. Its mouth is open making it looked surprised.

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They are seriously smart

Octopuses are clever. They can open jars (both from the inside and the outside). They can build a fortress of stones around them as they sleep to protect them from predators. And they are masters of camouflage – the mimic octopus impersonates a deadly sea snake to scare off predators and other species hide and protect themselves by carrying around a shell or coconut.

A brighly coloured yellow octopus with blue rings on pink coral.

A blue ringed octopus found in Raja Ampat, Indonesia

Image credit: Dani Escayola/Ocean Image Bank

Octopuses are in trouble

They are more than 300 different species of octopus (that we know of). Like all marine life, they are seriously threatened by pollution, loss of habitat and over-fishing. The decline of octopuses also threatens the sharks, birds, whales, dolphins and fish that eat them. The marine food web is deeply interconnected, so protecting every species counts.

If you’d like to help protect octopuses, here are some ideas:

  • Use non-toxic cleaning products in your home and at work.
  • Reduce your consumption of fish and only buy fish recommended in our Good Fish Guide.
  • Introduce more organic food into your diet, which is not sprayed with pesticides or chemicals that run off into rivers and the sea.
  • Reduce how much single-use plastic you use.
  • Wash synthetic clothes in a protective washing bag to prevent microfibres ending up in the sea.
  • Purchase goods in local shops to reduce the disturbing noise and carbon emissions associated with international shipping.
  • Support us by donating or volunteering at a beach clean.
A brown octopus on the sea floor. Behind it is an azure sea

A common reef octopus  |  Image credit: Vlad Tchompalov

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Marine Conservation Society

20 Apr 2021