Week Six: Blue-Ringed Octopus

Common Name: Blue-Ringed Octopus

Scientific Name: Hapalochlaena lunulata

Not-So-Fun Fact: The blue-ringed octopus carries an extremely venomous bite caused by colonies of bacteria in its saliva which produce a neurotoxin called tetrodotoxin. Tetrodotoxin prevents sodium from being transported across membranes in the brain and can kill those exposed in less than an hour.

Domain: Eukaryota

Kingdom: Animalia

Phylum: Mollusca

Class: Cephalopoda

Order: Octopoda

Family: Octopodidae

Genus: Hapalochlaena

Species: H. lunulata

Description: The blue-ringed octopus is a small octopus with bright yellow skin covered in blue circular markings. Its vivid coloration warns potential attackers of its extremely venomous bite. The greater blue-ring’s mantle can grow up to 55 millimeters, but a more average length for adult individuals is 25 to 40 millimeters. The skin is covered in pebbly papillae. When agitated, the yellow hue of the octopus’s skin deepens to golden brown; the blue rings thicken, brighten, and may pulsate; and the papillae become smooth.

Environment: The greater blue-ringed octopus is native to the Indian and Pacific oceans, and inhabits a range stretching from Sri Lanka to northern Australia, Papua New Guinea, the Solomon Islands, the Philippines, and Indonesia. Visitors to Australian beaches are put at risk by the presence, and a few fatalities are reported each year as a result of bites or extended contact with the octopi.

Reproduction & Development: This organism reproduces sexually, and the mating process is a very long and close process. The females lay eggs whose gestations last about two months, the total time depending on temperature. Their offspring become sexually mature after about four months and usually live for about eighteen months. During gestation, the eggs are held by the female’s long tentacles and kept close to her body.

Nutrition: The blue-ringed octopus is a very small predator, and normally feeds on small crabs, hermit crabs, and shrimp dwelling near the shore. They eat such crustaceans by attacking them, wrapping their bodies around them, and puncturing their carapaces with their sharp, venomous beaks.