Nigel Marsh focuses his attention on a unique Australian marine species, the southern sand octopus.
Australian waters are home to an incredible number of octopus species. Around Australia are 30 species of octopus, and while many of the tropical species are also found in the neighbouring countries of the Indo-Pacific region, the ones found in temperate waters are unique to the nation. One of these unique temperate octopus is the rather strange southern sand octopus.
Australia’s Hidden Cephalopod: The Southern Sand Octopus
The southern sand octopus (Octopus kaurna) is well named as this octopus likes to hide in the sand. Orange in colour, the southern sand octopus is unlike most octopus in that it lacks the ability to change colour, having no chromatophores in its skin. However, as it hides in the sand by day and emerges at night to feed on small crustaceans and fish, the ability to change colour would be wasted in the dark. A medium-sized octopus, the southern sand octopus can have an arm span of up to 50cm. They also have very thin arms and can stretch their head and body to appear very thin and elongated.
The sand burrowing behaviour of the southern sand octopus is quite unique. Most cephalopods that bury in the sand simply cover themselves with a layer of sand. The southern sand octopus uses its siphon to blast water into the sand, which loosens the sand particles like quicksand, allowing the octopus to quickly burrow with its arms. It leaves two arms extended to the surface to create a ventilation shaft and uses mucus to stabilize the sand around it, creating a cocoon burrow.
Where to See the Southern Sand Octopus in the Wild
Little is known about the life cycle of the southern sand octopus. Mating swarms have been observed, with a group of these octopus piled on top of each other. They probably only live for one year, dying after mating and egg laying. The females producing large eggs, which are most likely hidden in the sand. The southern sand octopus is found in shallow sandy bays off South Australia, Victoria, Tasmania and southern New South Wales.
They are only seen at night, with the many jetties and piers of South Australia and Victoria the best place to see one or several during a dive. They are easy to observe and photograph at night as they don’t appear to be too disturbed by torch light, unlike some other cephalopods. The southern sand octopus is one of the most unique cephalopods divers will encounter in the temperate waters of southern Australia.
Nigel Marsh
Nigel Marsh is an Australian underwater photographer, photojournalist and a budding marine naturalist. He has a great love of all marine life, no matter how big or how small. He is the author of several dive guides and natural history books, teaches underwater photography and leads special photography group tours. Visit his website for more information: www.nigelmarshphotography.com
Frequently Asked Questions
What makes the southern sand octopus unique?
This species can’t change colour like most octopuses. Instead, it burrows into sand using jet-propelled water from its siphon and creates a mucus-lined cocoon for protection.
Where can divers see the southern sand octopus?
They’re found in shallow sandy bays across South Australia, Victoria, Tasmania, and southern New South Wales—most often seen during night dives around jetties and piers.
How does the southern sand octopus hide from predators?
It blasts water into the sand to loosen it, burrows beneath the surface, and stabilises the sand with mucus, leaving two arms extended as a breathing shaft.
When is the best time to see a southern sand octopus?
At night. The species is nocturnal and emerges after dark to hunt small crustaceans and fish, making evening dives the best time for sightings.
