OLogy Cards > blue ringed octopus

blue ringed octopus

Many animals and plants use color to warn predators to stay away, and the blue ringed octopus is no exception. When this small mollusk is disturbed, blue circular rings light up all over its body. This colorful display is the octopus's way of saying, "Stay back—I'm about to bite!" One of the deadliest animals in the sea, the blue ringed octopus has a venomous bite that can instantly paralyze and kill a human.

Stats

Scientific name: Hapalochlaena lunulata
Size: about 8 inches long
Diet: crabs and fish
Habitat: shallow coral reefs off the coasts of Papua New Guinea
Characteristics: yellowish-brown skin; glowing blue rings appear when provoked
Significance: helps keep populations of crabs, fish, and other marine organisms in balance

Stumper

The radula is found inside which part of an octopus's anatomy?

its skull

its arms

its mouth

Correct!

Octopuses use their powerful mouths to bite down on prey. The blue ringed octopus grabs its prey with its powerful arms, and bites down with its teeth or radula. It then releases powerful venom called tetrodotoxin that paralyzes the victim.

Stumper

The female blue ringed octopus lays her eggs in a place called:

a den

a pouch

an attic

Correct!

Octopuses hide under rocks and inside small crevices called dens. A female octopus often covers up the opening of the den with rocks to provide a safer and more secure place to care for her eggs.

Fact or Fiction

If the blue ringed octopus loses one of its eight arms, another one will grow back in its place.

Fact

Fiction

Fact

Unlike most animals, if an octopus loses one of its eight arms, it has the ability to grow another arm in its place. This process is called regeneration.

Fact or Fiction

The bite of a blue ringed octopus is extremely painful.

Fact

Fiction

Even though these amazing mollusks are usually not aggressive and would rather bite crabs than people, they can inflict painless bites to defend themselves against predators.

Image credits: main image, courtesy of Roy Caldwell.

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