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DISPLAYING POSTS TAGGED: cephalopods (2)

Octopus on dry land

Author
by Kate C
Publish date
24 November 2011
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A YouTube video, Octopus Walks on Land at Fitzgerald Marine Reserve is doing the rounds at the moment and generating a bit of online discussion about this fascinating behaviour.

Dr Julian Finn filmed a similar event in Broome a few years back where a small, unnamed octopus (Abdopus sp.) crawled between rock pools at low tide. He says that it's not uncommon for intertidal octopuses to roam between pools in hunt of prey such as crabs or fish. They may also flee their tide pool to escape the attention of bigger, hungrier octopuses! In this video, he explains more about these terrestrial adventures.

 

Watch this video with a transcript

Like all cephalopods, octopuses breathe through gills and won't survive for long out of water. Julian has only seen octopuses crawl over dry land where the chance of them being trapped out of water is minimal. In captivity, it's not unknown for octopuses to turn up in strange places after breaking out of their tanks – including one that was found in a staircase!

Links:

MV Blog: Blue-ringed octopus project

MV News: Argonaut buoyancy

MV News: Tool use in Veined Octopus

Death by octopus

Author
by Ursula
Publish date
4 November 2011
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Ursula Smith works in the natural sciences collections at Museum Victoria. Though a palaeontologist by training she finds all the collections fascinating and swings between excitement at all the cool stuff in them and despair at the lack of time to look at it all.

Given that they're the subject of some major research at the museum there's been a lot of talk about blue-ringed octopuses around the Sciences Department at the museum recently. As I grew up in the UK, I've never seen one so when I heard that there was one on display in Melbourne Museum I headed down to find it so I could see what these fearsome beasts I'd heard so much about look like in the flesh. But to my surprise it didn't look as exciting as I had expected - there was not a blue ring to be seen.

So now I know what any Victorian schoolchild should be able to tell you: a blue-ringed octopus only displays those eponymous blue rings when it feels threatened or disturbed and most of the time it's just a plain brown or greyish colour.

Blue-ringed octopus in jar Blue-ringed octopus (Hapalochlaena maculosa) specimen in a jar on display.
Image: Genevieve Ooms
Source: Museum Victoria
 

Despite this specimen's disappointing colouration though, it does have a fascinating story attached to it. Look closely at the label in the picture and you can just see that it bears the slightly ominous "...bit and caused paralysis" which is a transcription of the note made in the museum registration book when this specimen was donated: "This specimen bit and caused paralysis in its captor". As it happens, this is the actual individual, collected on Christmas Day, 1962, that lead to much of the public awareness about the dangers of the blue-ringed octopus.

It perhaps seems a little strange that it wasn't known that this species is so dangerous until so recently - despite the southern species being described in 1883, it wasn't until 1954 that the bite of any blue-ringed octopus was discovered to be deadly. The first recorded fatality – one of only two in Australia to date – was in spring 1954 near East Point, Darwin, but the culprit was originally misidentified because it got away and was then identified based on another octopus the victim's friend pointed out as looking the same. The victim, a 21 year old seaman, Kirk Dyson-Holland, died within two hours of being bitten after picking up an octopus while spearfishing.

For a while, it was largely assumed that the danger of death-by-octopus was restricted to the north or perhaps to people with specific allergies, but then nearly a decade later, on Christmas Day 1962, Arthur Thompson, then 33, was bitten on the hand by a southern blue-ringed octopus at Ricketts Point, Beaumaris in Port Phillip Bay just round the coastline from Melbourne (where they are still found – there was a report in a local paper of one being picked up by a 4 year old just this May). The Registrar of the Alfred Hospital Clinical Research Unit where Mr. Thompson was taken reported:

The patient held it on the back of the hand for a minute of two, and after putting it down noticed a speck of blood on his hand, there had been no sensation of sting or bite. A few minutes later he felt a prickling sensation around his mouth which rapidly became generalized and within fifteen minutes was almost completely paralysed.....Just after admission spontaneous respiration ceased and he was respired for about an hour. Thereafter he made a steady and uneventful recovery of his muscle power. He was well the next day, chest X-ray was clear and he was discharged.

Happily, Mr. Thompson recovered after an hour of artificial ventilation while the poison wore off and nobody has actually been killed by one in Victoria, but the story of this octopus, reported widely in the news, lead to a much greater awareness of the danger of disturbing the blue-ringed octopus. There has only been one reported fatality in Australia since, near Sydney in 1967, partly due to better understanding of the dangers and partly because the blue-ringed octopus is, fortunately, really quite laid back and won't bite unless provoked.

Mr. Thompson's brush with death obviously wasn't the first time someone was bitten by one of these octopuses and it is likely that there have been other deaths before and after, many of which would have been reported as unexplained. In fact, there was an incident a year earlier in December 1961 at Cowes, Phillip Island, with almost identical results: the victim was bitten, felt gradual paralysis until he stopped breathing, was given artificial respiration for a couple of hours and then recovered to be discharged from the hospital on Christmas day exactly a year before Mr. Thompson was admitted. That octopus wasn't kept so we don't know for sure what species it was, but it seems likely that it was also our friend the blue-ringed octopus.

So next time you visit the museum, keep an eye out for this specimen in the Port Phillip Bay cabinet on the ground floor – just turn left as you come past the ticket desk. It won't bite!

Blue-ringed octopus swimming Blue-ringed octopus, Hapalochlaena maculosa.
Image: Julian Finn
Source: Museum Victoria
 

 

References:

Report of the first fatality in Australia: Flecker H, Cotton BC (1955). Fatal bite from an octopus. Med J Aust 2:329-331.

Injuries to man from marine invertebrates in the Australian Region. Cleland, J. B. and Southcott, R. V. 1965. National Health and Medical Research Council, Canberra, pp282.

 

Links:

Australian Women's Weekly article from 1967

Report from the Moorabbin Leader from May 2011

MV Blog post about Julian's research

Marine Life exhibition

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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