Which octopus is dangerous?

All octopus, cuttlefish and some squid are poisonous, according to a new study. The largest known octopus species, the Pacific giant octopus, can reach sizes larger than 16 feet (5 meters) in diameter. But the blue ring of 5 to 8 inches (12.7 to 20.3 centimeters) is still the only one dangerous to humans. The blue-ringed octopus is the most venomous of all octopus.

This type of octopus has venom that contains tetrodotoxin, a substance that acts as a neurotoxin for humans. Contrary to what was known, all octopuses are poisonous, according to a new study. Researchers knew that the blue-ringed octopus was full of poison. Now they say that all octopus and cuttlefish, and some squid are poisonous.

In fact, they all share an ancient and common venomous ancestor, the study indicates, and the work suggests new avenues for drug discovery. The world's deadliest octopus is called the Blue-ringed Octopus and can only be found among the warm, shallow waters of the Australian coast. Although octopus and squid are formidable fighters in nature, they are usually not dangerous to people. That doesn't mean they're always harmless.

Some species are especially well equipped to defend against larger creatures, and are strong enough to kill a human if they feel threatened. They may seem less important to their size, but a bite from the beak of a blue-ringed octopus can lead to a devastating end. This octopus, found on the reefs and grass beds of the western Atlantic Ocean and in places such as the Caribbean, the Bahamas and northern South America, has a blue-green color. The main neurotoxic component of blue-ringed octopus is a compound that was originally known as maculotoxin, but was later discovered to be identical to tetrodotoxin, a neurotoxin that is also found in blowfish, rough-skinned newts, and some venomous dart frogs.

Fortunately, the Pacific Giant Octopus is known to be quite shy and generally friendly to humans, rarely using its dangerous characteristics to inflict damage. If you're looking for a non-venomous octopus that you can take home with you, this soft orange octopus plush from Gage Beasley won't poison you. Found in the Pacific Ocean, the mimic octopus has poison in its saliva, which can cause paralysis and kill its prey. The ink clouds temporarily confuse the attacker and act as a decoy while allowing the octopus to swim away.

Although octopus venom is considered one of the world's deadliest substances, there have been people who have survived encounters with the tentacled creature. In the large blue-ringed octopus (Hapalochlaena lunulata), the rings contain multilayer light reflectors called iridophores. The common octopus is the most abundant species among all octopus and can be found all over the world. The reason this particular species is so deadly is because its venom contains a paralyzing neurotoxin called tetrodotoxin, which octopus can secrete from all areas of its body.

And to date, there have been only three deaths attributed to the Blue-ringed Octopus and its venom. Found on the Eastern Pacific ridge and near large colonies of giant tubularworms, this octopus is tiny, about 6 inches long. While most octopus species are not deadly to humans, it's important to remember that they are wild creatures.