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A mystery shell

Cuddlycuttlefsh

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#1
So, very once in a while I get a chance to go to near the shore on the eastern coast. I got a chance to collect this particular shell at Myrtle Beach. I've seen this is what is left after an octopus has drilled into clams, scallops, etc when they can't pry it open. What do you think, what are your thoughts on this shell, I'm really excited to see whether this shell WAS really the remains of a victim of octopus shell drilling. About 1" long in length and the hole is located in the back part of the shell. The diameter of the hole is about a millimeter and a half.

 

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tonmo

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#2
Hi Cuddlycuttlefish -- even though this isn't a "ceph care" issue, I've moved your thread from the Cephalopod Fact Check forum to this ID Requests forum. I think it's the best place...

...and I have no idea about the shell above, but am looking forward to the responses! :smile:
 

CaptFish

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#3
Whelks; a group of marine snails use their radula to drill a hole through the side of other mollusks, then kill them so that they relax and the shell can then be opened and the contents eaten.

the octos I have had did not drill holes, they would pry the shells open instead. I have seen them make a hole in crabs, but it was from biting, not a drilling action.
 

Cuddlycuttlefsh

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#4
Drilling yes, is not a common action for an octopus to execute. There could be a very large chance that their are other variables that caused this to happen to the shell. I believe octopus do not have fairly long attention spans am I correct? If I'd have to look at about 10-15 minutes of drilling vs desperately trying to pry open a clam or a mussel etc with a very good grip I'd move on.
 

ieatfalalfel

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#5
Do you know which species live in the Myrtle Beach are, you said thats where you found this shell. I go there twice a year and it would be interesting to look for octopuses. Also, I have seen shells like that with the hole in myrtle beach. Especially in North Myrtle, it seems.
 

Cuddlycuttlefsh

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#6
Hmm...I should do some research. First I might need to know where this shell came from, maybe that'll pinpoint an area that some species of octopuses dwell in. I have a good feeling this shell was more likely to be passed through currents rather than Myrtle Beach. My knowledge on shells remains lacking so this should be fun. Then again, there are many variables such as what Capt Fish said about that special mollusk. I'll see if there's any differences of the biological diversity and the local biota that dwell between those two areas that you mentioned.

If any one has any other encounters that they know of that relates to octopus drilling, what size of the hole should you expect from larger species to smaller species?
 

CaptFish

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#7
I'm almost positive it is from a welk and not an octopus. the holes i have seen made by octos are not round and symmetrical but instead they leave triangular shape.
 

Cuddlycuttlefsh

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#8
Okay well, I'll conclude that this is drilled by whelks. Also now, after observing it more the shell also happens to have been smoothed out by water currents and flows which does tell me this has a better chance of coming from somewhere else rather than Myrtle Beach. No doubt this shell has been in the water for a while after it was eaten or killed. I'm going to still continue to find out the species of octos that dwell near the beach though.
 

cuttlegirl

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#9
Hi Cuddlycuttlefish,

You are looking at shell predation by a moon snail. It is a perfectly round hole with beveled edges, correct? Octopus do puncture shells, but it will not be perfectly round - I will search for some photos of octopus predation. Your shell is an ark shell.

Here's probably way more information than you need, but there are some SEMs of octopus predation in this article.
http://www.icm.csic.es/scimar/pdf/61/sm61s2067.pdf
 

Cuddlycuttlefsh

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#10
I have to keep moon snails and whelks into my consideration. They both seem to be able to drill the same approximate sizes shown on my ark shell. But Moon snails spot of choice when drilling does seem to be in the back area of the shell which does seem to be present on the mystery( sort of) shell.
 

CaptFish

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#11
the hole location is why i suggested welks, as that is exactly where they are know to drill.
 

Cuddlycuttlefsh

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#13
Nice articles, including the one on post nine.
Sorry capt fish I didn't bother to check whelks spot of drilling, keep those corrections coming. That's how I learn.
 

Cuddlycuttlefsh

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#14
Ah hah! May this thread resurrect from the dead!
Got lucky, skimmed through some other shells looking for any potentials and what do you know! Triangular drilling hole, seems their was some intentional chips on the side made by something. And not to mention, the drill site isn't located on or near the umbo of the shell (well at least not so close as the last shell). If theirs any other key factors that help one distinguish a shell that is drilled by an octopus let me know. I'm still wondering if there are some things I may have missed, it's fine if it's not the real deal. Dump anything that comes to your mind on me!

some pictures that I took, much better quality rather than my ancient 2nd gen.



This is just a photo near some tape measure, its in inches just to give you guys more of an idea. Fairly small, not sure though. Would an octopus go through a long session of drilling just to get a hold of this little guy?



Chipped sides as you can see, a common strategy for an octopus.



View of the shell from above, kept it up so white light would pop out of the hole.
 

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Cuddlycuttlefsh

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#15
Yeah, I have a better feeling on this one. Those chips on the side is a really good give away. Do octopuses drill multiple holes or mainly just one? Thats another thing thats really puzzling me as well...:hmm:
 

tonmo

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#17

CaptFish

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#18
hmmmm, i posted two comments in here and neither one have appeared?

again for the third time.....i wasnt ignoring you i had a crazy busy week of exams when you posted.

Its hard to say for sure if that was an octopus or not. the hole looks more like the ones i have seen from octos, so its a definite possibility. the edges being beat up the way they are i think seems more like damage from the shell rolling around, but i'm not positive on that.
 

tonmo

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#19
CaptFish;185248 said:
hmmmm, i posted two comments in here and neither one have appeared?
Weird :hmm: ...well it's working now!
 

ieatfalalfel

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#20
CaptFish;185248 said:
hmmmm, i posted two comments in here and neither one have appeared?

again for the third time.....i wasnt ignoring you i had a crazy busy week of exams when you posted.

Its hard to say for sure if that was an octopus or not. the hole looks more like the ones i have seen from octos, so its a definite possibility. the edges being beat up the way they are i think seems more like damage from the shell rolling around, but i'm not positive on that.
I posted on this thread too, but mine was a couple days ago I think. Thats odd, has TONMO had vanishing posts before?
 

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