Arms and Brains

[Scouse]

Ok I have a couple questions to ask, they may seem a little silly but......

I wonder, are octopus, squid and other celaphods etc ever left or right armed (handed)?

and also, i believe an octopuses brain is doughnut shaped with the stomach travelling through the 'O', for want of a better explanation.

So in theory does this mean that an octopus, if over fed could, could sit back an say "WOW THERE!!! too much food...I cant think!!!"??

 

[tonmo]

So in theory does this mean that an octopus, if over fed could, could sit back an say "WOW THERE!!! too much food...I cant think!!!"??

ha!

Well, here's my train of thought, but I'm no expert...

Regarding an octopus being right or left "handed", I don't think it would apply... My theory (brace yourself) is that the way humans favor their right hand or left is closely related to balance. We stand upright, and have cumbersome bones attached to our muscles, and (of course) our muscles are moved to manipulate our bodies for movement. Because we're much more impacted by gravity than a free-floating, boneless octopus moving across the ocean floor (or floating in a water column), it would seem that we, as a species, are much more impacted by things like coordination than an octopus.

Have you ever seen an octopus move across an ocean floor? It's pretty graceful... doesn't look like one set of arms is more dominant than the other. Thay may or may not be related to the explanation I cobbled above, but in any event I would doubt they're lefties or righties.

With regard to eating, as I understand it, octopuses completely pulvarize and, in fact, liquify they're food before ingesting. Someone correct me if I'm wrong here, but I believe that while they gnash their food with their beaks, they're injecting some venemous substance(s) that further break the food down. As such, I don't believe they have a big ball of food sitting in their "stomach" as one might think. Completely different digestive process than we humans.

Perhaps?

 

[Jean]

weeeeellll about handedness, while I'm sure octis don't have handedness in the same sense as we humans , I have noticed that the octi's we hold in the aquarium will often have a marked preference for using the arms on one side or the other for exploring.

AS for pulverising/liquifying their food I'm not sure about Octis but squid who have the same brain/oesophagus arrangement certainly chew their food throughly. It makes it such fun to sort through!!!
J

 

[Scouse]

Well it seems this matter is still open for debate.

Personally I think it brings a whole new meaning to the term "ice cream headache!!"

But I agree it is quite graceful to see an octopus move across the ocean floor and it does seem they dont prefer to favour either side, although I suppose that would require the studying of a number of specimens over a period of time.

I think it makes sense that some may prefer to use certain arms for exploring once they have had more success with some arms, they will I suppose stick with them.

Actually, heres a thought........ Nancy if you read this, can you tell us which arms Ollie waves with and does he do a mirror impression of you or does he favour the other side?

Come on folks, more thoughts on the...."my bellies too full, I cant think errr was I left handed or right before I started eatin??" theory.

I would be intrested to know if octo's do actually inject something to liquidise the food theory, thats a goodun, sounds a bit like a fly or a spider........

 

[Steve O'Shea]

..... I've deliberately stayed away from this question (right- or left-handed), waiting for others to respond. It is a tough one.

The male 'Octopus' (sensu lato, as in loosest sense - that basically means any-old octopus with 8 arms, no fins, 2 rows of suckers ....., excluding all of those pelagic and finned octopus families) USUALLY has the third right arm hectocotylised (for spermatophore transfer), although a very few species have the third left arm hectocotylised. So, there probably is some favoring of one side of the body to another when it comes to performing certain functions. Whether this is right- or left-handed I wouldn't want to say. The arms also perform many other tasks, so even the hectocotylised one is beset with myriad suckers and looks pretty much like a normal arm (although is often shorter and possesses fewer suckers, in addition to having a pronounced [at times] web extending out to the arm tip [the spermatophoral groove]).

The paper nautilus, Argonauta nodosa, usually has the third left arm hectocotylised, although I have a few male's here on which the third right arm has been modified into a hectocotylus (enclosed within a pouch). Whether these are mutations or not, again I wouldn't want to hazard a guess. Perhaps it doesn't matter which arm 'does the business'.

On quite a number of specimens of one Benthoctopus species in New Zealand, one of the arm tips (one in particular) branches at the tip. Now this is a rather rare thing (arm branching), and certainly to find this same bizarre condition in a number of specimens of one particularly rare deep-sea species is VERY odd! Whether the branch was driven by recurring mutation or damage I simply don't know, but if it is damage-induced then there certainly has to be some right/left handedness of the animal (as a species rather than individual), with certain arms performing certain functions.

Another thing to consider is whether it is as much 'right & left handed' as 'front and back armed'. There is often a marked difference in sucker size, presence/absence of especially enlarged suckers on some arms, and relative arm length to indicate that certain arms perform certain 'functions'; on a right/left axis there might be symmetrical performance.

It is the kind-of question that you could answer and say 'no, absolutely no right/left handed' business, but that's the kind-of answer that could land you in hot water when speaking to someone who has done extensive behavioural or neurological work on these brutes. I have done neither so will reserve judgement .... it would make for a very interesting research project.

... and yup, the brain is like an 'O', with the oesophagus passing straight through it (a donut we call it).

Cheers
O

 

[Nancy]

In response to Scouse's query about which arms Ollie waves with:

He is usually in his den when he waves, and he is a tangle of arms - about every half an hour he rearranges his arms. So he tends to wave with whichever arm is closest to the front. When he gives a two-armed wave, the arms are side by side.

I'll observe this some more and report back anything of note. Unfortunately, right now Ollie is peeved with me, acting generally huffy, and is refusing to wave! I don't think this will last too long.

Nancy

 

[Scouse]

Well thanks to Steve and Nancy for the responses.

STEVE!! Wow, I had to go away and read that one a few times, very intresting, and yes it would be a good research project. I'd be surprised if somebody hasnt undertaken it, at least to some extent already.

There you go people at the NRCC, theres another crackin reason spend time with the little monkies an get paid for it!!

I think it does lead to beg the belief certain species have evolved to use some arms for particular functions, to gain suitability for their environment. Hence leading to favoured side in some cases.

Ive learnt something new here on how octopuses pro-create! To be honest with you I had never even though of how they "got it on!!!"


I take it the oesophagus is what we would call the stomach in latmans terms. How do you pronounce that? Only so I can sound like a smart arse at times!!!!

It will be cool to see if Ollie is a lefty or a righty!!!

Speakin of evolution above....I have a mate who has a theory on evolution... ...bit dodgy but here goes.... He reckons that one day men will evolve to create a hand to grow out of their elbows for all those times the girls walk past and brush their boobs against them in bars!!! LOL

I suppose he has a point to some extent! There we have it ladies an gentlemen, another loose looney on the streets!!!

 

[um...]

Here is an article from BBC News (from 2 years ago) that is sort of related to this discussion:

http://news.bbc.co.uk/1/hi/sci/tech/1529397.stm

It seems that a significant portion of the motor control of an octo's arms is actually carried out by neurons located in the arms and not in its "brain". I've also read that, at least in one experiment, a severed octopus arm placed in the vicinity of food was able to grasp the food and move it to a location near where the animal's mouth would normally be. I'm hoping that someone here might have more current/complete info regarding these results.

I wonder if there might actually be some "computational" neural circuitry in the arms, allowing a form of reflexive learning to take place. In that case, Scouse's hypothesis:

...some may prefer to use certain arms for exploring once they have had more success with some arms, they will I suppose stick with them.

would make a lot of sense.

This is a fascinating topic, and I'm surprised Scouse would dream to call the question "a little silly".

 

[Scouse]

Nice one um...

That was a good article on the bbc, this is definetley somthing that should be studied....the more we know, the more we understand.

woo better slow down there, think im goin into chinese proverb mode!

'he who has eight arms, must wonder what happened to his legs.' LOL

Well it turns out there lots more to go on this......


Just a thought actually.....where is the great white north? I always was poo at geography!!! LOL

We dont have a North and South were i come from you see.

My guess is canada, but your lookin at the BBC website, so I avnt the foggiest!!!

 

[um...]

That was a good article on the bbc, this is definetley somthing that should be studied....the more we know, the more we understand.

woo better slow down there, think im goin into chinese proverb mode!

'he who has eight arms, must wonder what happened to his legs.' LOL

Heh, heh. So true, though.

You guessed right. I'm posting from Canada, near Toronto, Ontario (which is not all that great, not white just yet, and not really very far north). You from London, England (home of the world's best beers)?

Here's another link that you (and others) might find interesting if you haven't stumbled across it yet:

The Octopus Research Group

I wish I'd gone into ceph research, instead of wasting the last 7 years of my life...

 

[Jean]

Intresting site um, that octi on the home page with swirling mantle looks how my brain feels this morning I guess I haven't had enough yet! I've just got to keep repeating my mantra (for maintaining sanity, when nothing is going well!)

"statistics are my friends, the computer is my friend, the photocopier is my friend" repeat as required

J

 

[um...]

"statistics are my friends, the computer is my friend, the photocopier is my friend" repeat as required

Statistics are evil (eveeeeeeeel). Computers are trying to kill me (and probably everyone else). Don't even get me started on photocopiers... (broke one at the office last month)

, on the other hand, is very very good.
(at least mine is)

 

[Melissa]

I wish I'd gone into ceph research, instead of wasting the last 7 years of my life...

Heh he, me too. What's your degree in? I'd never have hacked my way through the biology. This way, it's far more fun.

Melissa

 

[um...]

Heh he, me too. What's your degree in? I'd never have hacked my way through the biology. This way, it's far more fun.

Melissa

My first is in applied math (whatever the !*%# that is). I'm doing a very half-arsed job of getting another in comp-sci, since I was 1/3 of the way there already. For some stupid reason, I never took any biology. Guess I figured life didn't really need to be interesting. I'm now forced to learn my biology on the side, which would be great if I had the time. Maybe I should try to get fired...

What's your unbiology background?

 

[Melissa]

Gah, some of my work is international and US policy analysis. I prefer shorter-term research projects, so I've got a long-term editing project now. Oops!

But more on topic - how did you get interested in cephs? Friends in bio and natural resources drew me in with anecdotal information, and I was more drawn to marine invertebrates like jellies and octopuses and anemones, probably because tentacles are pretty. Is there an emoticon for "vapid"?

Melissa