Are Octopuses Dangerous? (What to Do if an Octopus Attacks)

Octopuses generally aren’t dangerous to humans and their venom is mostly harmless to us. They rarely attack humans as they don’t see us as prey. If an octopus becomes aggressive, pull away, try not to get bitten, and swim towards the surface.

Octopuses seem intimidating. These eight-legged monsters can look like horrifying killing machines, but in reality, the opposite is true: they are gentle, curious, and easily frightened creatures that rarely grow bigger than a child.

Still, caution while around octopuses is receommended, as they can harm to us. But how exactly? And when do they get aggressive?

This article discusses everything about the dangers of octopus encounters, including their strength, venom toxicity, and fighting tactics.

Are Octopuses Dangerous?

Octopuses are rarely dangerous. They flee when they are disturbed and only attack if they are being harassed for a long time. Their most dangerous attribute is their venom, but only blue-ringed octopuses are toxic enough to kill humans.

There are only two reasons for an octopus to attack: hunting or harassment.

Octopuses hunt for small marine animals. They exclusively attack animals smaller than them and do not see bigger creatures as prey. As most adults are bigger than octopuses, confrontations initiated by octopuses are unlikely.^[1]

There are some octopuses that can grow bigger than humans. Although they rarely weigh more than 110 pounds, they might overpower smaller people. 

Here are some of the biggest octopus species:

• Giant Pacific octopus (14 feet)
• Seven-arm octopus (11 feet)
• Maori octopus (9.8 feet)
• Southern giant octopus (six feet)

Octopuses behave like prey when they are disturbed. They flee when they sense danger, which is often the case when humans approach them. If they are not harassed further, they will not turn aggressive.

Do Octopuses Bite?

Octopuses bite their aggressors when they are cornered. Their bites can be painful and cause infections, but small species only leave painless marks. Venom is injected with each bite, but most octopuses’ venom is harmless.

Although octopuses prefer to flee rather than fight, their bites can leave nasty wounds. When they are cornered, they lunge at their aggressors, wrapping their arms around them and biting them. 

Minute octopuses, like the inch-big Octopus wolfi’s^[2] bites are painless, but even the smaller species can cause excessive bleeding.^[3]

Octopuses inject venom with their bites. They have paralyzing toxins transmitted via their saliva. Most octopuses have weak venom, but blue-ringed octopuses are toxic enough to kill about 26 humans.^[4]

If you see an octopus with the following description, stay clear:

• Eight to twenty inches long
• Bright yellow, orange, or pale skin
• Vivid blue rings on the body
• Blue lines on the body (blue-lined octopus)
• Is in the Pacific and Indian Oceans (from India to Japan, down to Australia and New Zealand)

Do Octopuses Attack Humans?

Octopuses rarely attack humans. They only become aggressive after prolonged harassment. Some octopus species can kill humans with their venom, but they rarely attack humans and there haven’t been any reported cases of them eating people. About eleven people have died due to octopuses’ venom.

On rare occasions, octopuses might attack humans unprovoked. This is likely to occur during senescence: a life stage after mating where octopuses are dying, characterized by erratic behavior and self-harm.

Can an Octopus Kill You?

Some octopuses can kill you. Large species have muscular, long arms that they try to wrap around you when they turn on the offensive.

Small, venomous octopuses are more dangerous. The blue-ringed octopus’ venom can kill adult men in 20–24 hours. Although many survives their bites, it is best to not approach them as there is no antidote.^[5]

There are four octopus species that can kill you with their venom:

1. Greater blue-ringed octopus
2. Southern blue-ringed octopus
3. Blue-lined octopus
4. Hapalochlaena nierstraszi

Do Octopuses Eat Humans?

As of 2022, there haven’t been any recorded cases of octopuses eating humans. Their beaks are small and specialized to break down shells and cut off bite-sized pieces. Octopuses do not see humans as prey.

How Often Do Octopuses Attack Humans?

Octopus attacks are extraordinarily rare. Humans have recorded octopus attacks since ancient times, but they are few and far between. Estimates state that the deadliest blue-ringed octopuses have taken about 11 lives.

Unprovoked octopus attacks rarely happen. If you get attacked by an octopus without harassing it, it perceived your presence as a threat, felt backed into a corner, or couldn’t think straight due to senescence.

Dangers of Octopuses

Octopuses rely on their strength, intelligence, speed, agility, venom, and camouflage when they attack. Larger octopuses are more likely to attack you head-on, while small octopuses opt for small bites and venom usage.

As intelligent creatures, octopuses avoid any unnecessary confrontation. When it comes to self-defense, they flee, squirt ink, and escape into a small crevice. 

Attacks from larger octopuses are more straightforward, as they wrap their arms around you and try to bite you.^[6] Smaller octopuses try to stay out of sight and rely on their venom rather than sheer strength.

Capability	Description
Strength	Largest giant Pacific octopuses weigh about 110 pounds and are 14 feet long. They have muscular arms that they wrap around their aggressor.
Intelligence	Octopuses are highly intelligent invertebrates with good awareness and logic. Some developed tool usage, like the male blanket octopuses with man o’ war tentacles.
Speed	Octopuses’ jet propulsion (filling their mantle cavities with water and releasing it with high velocity) helps them swim at 25 mph.
Agility	The arms can extend and contract. Each of the eight arms is controlled by a mini-brain, making them semi-autonomous in decision-making.
Venom	Most octopuses have weak paralyzing venom. Blue-ringed octopuses have potentially fatal venom. It is transmitted through saliva.
Camouflage	Octopuses have chromatophores (small organs with pigment sacs) under their skin. These change octopuses’ skin color and texture. Octopuses use these to ambush.

What to Do if an Octopus Attacks You?

Octopus attacks can be avoided by not approaching them. If they jump on you, pull away, struggle, don’t let them take hold of your arms, peel the suckers from yourself, and swim to the surface.

The easiest way to avoid octopus attacks is not to get near them at all. They will flee if they are disturbed, so if they aren’t followed, they are unlikely to attack you.

If an octopus attacks you, you should do the following:

1. Pull away before it can wrap its arms around you.
2. Struggle constantly. Octopuses tire quickly.
3. Keep your hands free from its grasp.
4. Peel away the suckers. It might be painful but it’s vital to break free.
5. Octopuses anchor themselves to a stable surface, so detach them.
6. After breaking free, swim to the surface. They are unlikely to follow you.

Are Octopuses Friendly?

Octopuses are more curious than friendly, but some are known to play and bond with humans. Wild octopuses may recognize and communicate with people.

Octopuses are intelligent and curious creatures. If they do not flee in your presence, they will likely approach you with interest. Some octopuses may communicate with you and ask for your help.^[7]

Can Octopuses Be Kept as Pets?

Octopuses can be kept as pets, but they need extra care and special conditions to survive in captivity:

• Sealed, spacious water tank
• Around 8.2 pH
• Copper-free living space
• 60-80 °F
• Feed 2–4% of its body weight
• Feed animal products (frozen shrimp, mollusks, anchovies)
• Water salinity between 1.022-1.023
• Rocks and thin sand layer

Conclusion

Octopuses are generally not dangerous. They rarely attack humans unprovoked and flee when they sense danger. They turn aggressive when further harassed or when they hunt. Their weapons include their strength, intelligence, and venom. 

Only blue-ringed octopuses have strong enough venom to kill humans. If an octopus attacks you, try to break free and struggle. It is likely to tire quickly and release you. Wild octopuses are often curious and approach you with this mindset. Captive octopuses need special conditions to survive.