Episode 293 – Blue-Ringed Octopus: Uh-Oh Spadeadly-Os

“…and today we’re talking about spicy calamari, but not really. More on that later.”

When you’re a teeny tiny cerulean cephalopod in a big bad cephalopod’s world, you need to have some tricks up all eight of your sleeves. The blue-ringed octopus’s diminutive form hides a deadly secret to deter predators that may want to snack on some calamari. But that’s what happens when you have a good head on all eight of your shoulders here in Life, Death, and Taxonomy.

Description of the Blue-Ringed Octopus

  • As the name suggests, it has large blue rings (7 to 8 millimeters in diameter) all over their bodies.
  • Their heads are cone-shaped with a loose sock-style nub at the top.
  • Depending on their environment, they come in varied colors, including white, tan, yellow, brown, blue, and purple.
  • They also have blue lines on their eyes.

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We don’t  have a new Measure Up intro.

Dave from Penguins of Madagascar


  • 3.9 inches (10 centimeters)
  • How many pelomyxa go into the blue-ringed octopus?
  • Hint: Pelomyxa is a genus of single-celled flagellar amoebae that are the largest amoebae in the microverse. They are large enough to see with the naked eye. You might find them in ponds. It’s difficult to tell how many species there are because identifying differentiators in amorphous blobs is difficult. 
  • 20 pelomyxa. Pelomyxa sometimes grow to 5 mm. 


  • 2.8 ounces (80 grams)
  • How many blue-ringed octopals go into the weight of a Fender Stratocaster? 
  • Hint: A standard stratocaster is made of what is called tonewood, which is special woods that are good for making woodwind and acoustic stringed instruments. They include ash, maple, cedar, rosewood, and walnut.
  • 45 blue-rings. A stratocaster is around 8 pounds.

Fast Facts about the Blue-Ringed Octopus

The blue-ringed octopus lives in tropical and subtropical waters found in the Indo-West Pacific region, such as Sri Lanka, the Philippines, Australia, Papua New Guinea, the Solomon Islands, and Vanuatu.

It prefers shallow benthic waters among rubble, reefs, and sandy areas. Like most of its octokin, it lives in a burrow and emerges to mate or feed.

Their favorite food is crustacean in nature, specifically crabs and shrimp. But they will also eat fish, though they are harder to catch.

Most cephalopods that change color with chromatophores, do so to blend into their surroundings or to completely disappear. But the blue-ring uses chromatophores and iridophores to flash their rings. Flashing serves as a warning to predators and rivals.

Major Fact: Uh-Oh Spadeadly-Os

  • Most octopuses rely on their speed and camouflage to avoid becoming a seafood snack
  • But as a little guy, BRO isn’t very fast, and having bright blue spots all over you doesn’t help too much with staying hidden
  • So a new defensive tactic is needed
  • If threatened BRO will try and swim away, but if that doesn’t work, it will turn and flash its danger discs at you. If you get too close after that, you’ll get a nasty nip.
  • The neurotoxin is present in creatures such as pufferfish, rough-skinned newts, and certain poison dart frogs. This toxin, known as tetrodotoxin, operates by blocking sodium channels. Its action leads to rapid onset of motor paralysis and respiratory failure shortly after exposure. 
    • BRO has developed sodium channels that are immune to the effects of tetrodotoxin. 
    • The source of this toxin is bacteria located in the octopus’s salivary glands.
  • When introduced into a victim’s system, this venom can trigger symptoms including nausea, respiratory arrest, heart failure, complete paralysis, loss of vision, and even death in a matter of minutes if left untreated. 
    • In most cases, death occurs due to the paralysis of the diaphragm, resulting in suffocation.
  • Tetrodotoxin can be found in nearly every organ and gland of BRO’s body and it doesn’t impact its normal functioning.
    • Mother BROs will inject the neurotoxin into her eggs to make them generate their own venom before hatching.
  • As many as 16 people have been killed by BRO

Ending: So flash your fruit loops, be a BRO to those around you, and place your enemies’ hearts under arrest like the blue ringed octopus