When is a giant octopus not a giant octopus?

A new story doing the rounds earlier this week reported on a ‘foolhardy’ dolphin that suffocated whilst trying to eat a giant octopus. You can read the story here at New Scientist. The story is based on a short note paper published in Marine Mammal Science and its one of those nice little papers that describes a rare behaviour to add to the anecdotal record of behaviour between cetaceans and cephalopods. The Marine Mammal Science paper goes into grim detail about how an octopuses arms and suckers can remain active up to an hour after the ‘head has died’ and in this instance the suckers were still firmly to the Indo-Pacific bottlenose dolphin’s larynx, oesophagus and tongue during the autopsy.  The story was circulated fairly widely in the ‘science tabloid’ outlets and news websites however all is not as it seems.

Headline from the New Scientist reporting

Many stories lead with the headline about a giant octopus and some sort of judgement of the dolphin involved- greedy, foolhardy- but the reporting of this story is a nice example of when engineering a clickable headline and story is actually a bit misleading. At its worst we called say this was fake news. But this is exactly the kind of example I like to use when teaching students about the difficulties of striving for readability and accuracy as well as the wonderful complication of language especially when it comes to science. So when is a giant octopus not a giant octopus? Read on to find out.

When it isn’t an Octopus at all!

This is perhaps the weakest of the arguments but a fun one to think through anyway. The poor cephalopod in this instance, which wasn’t identified to species on many sites, was a Maori octopus, Macroctopus maorum. Which is an octopus in the octopus family octopodidae but not one of the 100 plus species in the genus Octopus. I think it would be a stretch to say that a Macroctopus wasn’t an octopus on these grounds just because the widely accepted common name happens to also be the name of a genus. Examples like this where there is a conflation between common names and technical names creates nonsense like sea stars vs starfish and whether apes are monkeys or not.

When it isn’t a giant octopus!

More fun and games with language. There are groups and species which can be informally referred to as giant octopuses. Specifically, the species in genus Enteroctopus are sometimes called giant octopus because the largest species, Enteroctopus dofleini, A.K.A the North Pacific giant octopus, can reach wights of over 70 kilograms and a length of over 3 metres. Confusingly, the seven-arm octopus (which doubly confusingly doesn’t have seven arms, it has eight), Haliphron atlanticus is potentially bigger that Enteroctopus dofleini but isn’t supported by accurate measurements of complete individuals. So the seven-arm octopus is also a candidate for being a ‘giant octopus’. Our dead dolphin wasn’t trying to eat either of these species so on one level we can say it definitely wasn’t a giant octopus that did it in for the dolphin. Fake news!

When it isn’t a particularly big octopus for its species!

Once extracted from the mouth and throat of the dolphin the Maori octopus was measured and weighed by the biologists who published the observation and came in at 2.1 kg and had an arm span of 130cm. Larger members of this species have been weighed at 12kg with a length of 2m and arm span of over 3m. So this poor octopus (not Octopus) wasn’t even that big for it’s species. Using humans as a comparator I don’t think anyone would consider someone who is a sixth the weight or a third the height of the tallest recorded humans would be considered a ‘giant’.

So when might a not-actually-that-big-an-octopus be considered a giant octopus then?

When the media wants you to read the story!

When I’ve written for news outlets there is normally a whole department dedicated to the dark art of search engine optimisation to try to ensure that as many people as possible click through (whether or not they read the article is another thing) to articles and stories. I’m sure that a quirky story like ‘Dolphin chokes on octopus’ would garner some attention but adding the word giant and throwing in a judgement on the ‘foolhardy’ dolphin presumably helped the story go much further and sounds more like a rare spectacle than a less fantastical biological observation. Interestingly at no point in the Marine Mammal Science paper do the authors suggest that the octopus was ‘giant’. Other incorrect details were reported too which didn’t come from the study itself. The New Scientist article linked to above reports that “A post-mortem examination revealed one octopus tentacles extending down the dolphin’s oesophagus and the other seven stuck in the back of its throat”. Octopuses don’t possess tentacles, they have eight arms, tentacles are two extra appendages found in the ten ‘limbed’ cephalopods squids and cuttlefish so this is an embellishment from whoever wrote up the story.

When the readers likely don’t know much about the subject matter!

For me, this is the most frustrating aspect of lazy errors like the ones I’ve covered here. I can understand that news outlets are under pressure to gain as many clicks and shares as possible to generate their ad revenue and to earn a reputation for keeping on top of the latest news so synthesise the technical detail from scientific reporting into a quick read that can be digested in between mouthfuls of coffee. The New Scientist article condenses an eight page short paper into 386 words and commendably do actually link to the original paper (so many outlets, even ‘sciencey’ ones don’t).

In doing so they also introduce a number of errors or gloss over details in describing the octopus as a giant, in not naming the species of octopus and in talking about tentacles. I can imagine that the reason for this is because the detail (and attention to detail) is considered boring or not relevant to readers. They likely don’t know that there are different species of octopus, or anything about octopus anatomy so why muddy the readability by clarifying some of these details or at the very least ensuring accuracy? The problem with this is that its quite insulting to readers and subscribing to this mentality means that they likely won’t learn more about octopuses or climate science or sloths when these details are perpetually skirted over.

This instance is just one of hundreds that likely happened this week and you’d be forgiven for telling me to not worry about it and move on but the point I’d like to make is this is one small example of why I and many others try to instil a sense of critical thinking around each and every piece of news or research that comes out, or museum display or nature documentary or political commentary (because we all have the time) etc. and why even semi-respectable outlets get things wrong in their layer or interpretation. I’d only spotted this because I have a slightly more than passing interest in cephalopods so here I am pointing it out to others and of course, you shouldn’t just take my word for it either.


Klein, A. 2017. Giant octopus suffocates foolhardy dolphin that tried to eat it. New Scientist. https://www.newscientist.com/article/2132626-giant-octopus-suffocates-foolhardy-dolphin-that-tried-to-eat-it/

Stephens, N., Duignan, P., Symons, J., Holyoake, C., Bejder, L., and Warren, K. 2017. Death by octopus (Macroctopus maorum): Laryngeal luxation and asphyxiation in an Indo-Pacific bottlenose dolphin (Tursiops aduncus). Marine Mammal Science. http://onlinelibrary.wiley.com/doi/10.1111/mms.12420/abstract


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