mantis shrimp vs octopus


New member
I watched a show on TV recently that showed a mimic octopus, that pretended to be other

Anyone know whther mantis shrimps can do this also? I emailed the guy who runs the lurker site about it also...

Also, do mantis shrimps prey on octopus and squid and stuff? or just crabs, etc, and fish? Which one would be cooler to have, octopus or pet mantis?
Mantis is a LOT more realistic to keep then an octopus. I don't think that anyone would advise keeping an octopus unless you have a very large (over 300 gallon) tank and know a lot about them. Stick with the mantis, they can be in a 10 - 20 gallon tank and should be pretty easy to keep.
I think there is a type of mantis shrimp (Echinosquilla) whose telson (tail end) mimics a sea urchin (you can read about it in the saltaquarium article on mantis shrimps). The mantis uses this to block off the entrance to its home. In terms of behavioral mimicry I cannot think of any examples...

Squid octopus and other cephalopds are part of the diet of different stomatopods...spearers regularly catch squid and the occasional octopus... Dr Caldwell notes that even the very highly poisonous blue-ringed octopus are not spared...there are stomatopods that are seemingly immune to its toxin and kill and eat these octopi...
forgot to add:

mantis are definitely much easier to keep than octopus and octopus are relativly short lived critters...however octopus are a favorite of some people due to the fact that some consider it to be the most intelligent invertebrate... they're pretty cute too in a squishy sort of way...

they are both cool in their own way
Thanks! A mantis shrimp like a sea people seel one of those? definitely would be interesting to see one.
First off, it would take one big and mean mantis to kill even a small octopus, and It wouldn't be in a predatory situation. It would be self defense.

Secondly, cephalopods ARE the smartest invertebrates on Earth. Nothing else comes close.

Thirdly, you can keep an octopus in a tank as small as 20 gallons. To read about my experiences keeping one in a 29 gallon, see


Adam Woods
Gotta disagree with the post above on some things...

First off, equating intellectual prowess with being the ultimate fighting machine just doesn't hack it...octopi are soft relativly slow moving invertebrates and several researchers note that octopus constitute a regular part of the diet of not only stomatopods, but lots of fishes as well (many much dumber than cephalopods I'm sure).

Secondly, being enamored of octopus is great, but is not a good excuse for becoming blind to their limitations...octopus are very short lived animals who are not social and do not seem to show much interaction between individuals over prolonged time periods...some stomatopods are very long-lived animals with either social aspirations (mating for life) or with very intense interactions between individuals (for example competive interections between individuals for homes)--- this fosters adaptations (including very fast communication skills and sophisticated vision and manipulation of objects) to cope with a relatively competitive world...this doesn't mean mantis shrimp are smart (hell, I'm sure I could beat one in chess), but just because I am interested in them doesn't mean I'm going to wish this to be true...

Other than that I think octopus are incredibly fascinating reefer above notes some even seem to "mimic" other animals...
man, i guess i'm venting here...

"First off, it would take one big and mean mantis to kill even a small octopus,"

dude, many mantis shrimp ARE big mean mothers, and we're not talking about the small stuff that hide in live rock. Some spearers who regularly subdue large fish are nearly the length of a human forearm and move so fast they are a blur in slow motion cameras, and some are SO mean they can break safety glass and smash through the thickest conch shells...

remember, to many animals soft octopi are not the
"smartest invertebrates on Earth. Nothing else comes close."
they're just calamari on legs...


Well, you may think it is just my opinion, but I bet if you ask 100 marine biologists what the smartests invertebrates, 99 of them would say cephalopods and 1 would be wrong. If you choose to disagree with the opinion of science, be my guest.

And if you want to get into extremes of animals, 2 words, Giant Squid.

Yes, some fish do feed on cephalopods (squid for sure!), and certainly small octopuses (octopi would be mixing Greek and Latin, but it's acceptable) The Wolf Eel, for instance, but NO crustaceans are regular predators of cephalopods. That's like saying zebras hunt crocodiles. Certainly Zebras have killed Crocodiles, but it's not often.

What animal could kill the other one really isn't the issue, but if somehow you could tally every time an octopus and a stomatopod have fought in the ocean, I'd be nice saying 1% of those stomatopods killed that octopus.

As for your statement about slow moving animals, apparently you've never seen one move after prey. They are very fast, can change the color of their skin to match the surroundings, are venemous (especialy to crustaceans) and of course can ink.

Can show me where Roy Caldwell says that Mantis hunt octopuses?


[Edited by on 01-27-2001 at 10:01 PM]
man this is getting very interesting...thanks...

With regards to your contention that I should automatically believe what 100 marine biologists say, I'd have to argue: rather than take on faith what other people contend I'd like you to show me the EVIDENCE comparing octopuses to mantis shrimps...I am not arguing that octopus do not show some signs of intelligence (because they seem to, at least some rudimentary form), I'm just saying other invertebrates (including stomatopods) show the same thing (they're just not as cute and cuddly as cephalopods or have the same number of devoted "fans")

Here's a line from The Lurker's Guide:

"A few years ago at the meeting I gave a talk comparing the behavior of octopuses and stomatopods. I had a check sheet of about 25 characters where I compared them. Not surprisingly, the stomatopods came out way on top."

(from R. Caldwell who studies both octopuses and mantis shrimps)

With regards to octopuses as prey I don't have a library here with me..also the few literature available on stomatopods invariably simply says "mollusks" as prey, instead of becoming specific but still here are a few sources:

"The shallow water mantis shrimps live in burrows from which they hunt marine worms, snail, OCTOPUS, fish and other crustaceans."

FROM: The Unique Visual System of the Mantis Shrimp, American Scientist Vol 82:356

"Gut analysis showed that this animal (a spearer) is a typical carnivore and mainly ate .... SQUID Loligo edulis and fish"

FROM: Population structure and feeding behavior of the stomatopod crustacean Kempina mikado (Kemp and Chopra, 1921) in the East China Sea. Fisheries Science (Tokyo) 62(3): 397-399)

"I'm not sure I mentioned this before, but one
of the things that we have been working on is stomatopods killing and eating blue-rings (octopuses). The TTX (editor's note: a potent neurotoxin called tetradotoxin used by blue rings to capture and subdue prey),doesn't seem to faze them."

FROM: Lurker's Guide to Stomatopods (Roy Caldwell)

With regards to your mano a mano comments on mantis shrimps vs octopus, as far as I know stomatopods don't have black and white stripes running down their bodies...all stomatopods are carnivores, not herbivores. Here's a link to a comparison:

One comment:
"As for fights between octopus and stomatopods, it is hard to predict....In general, squillids don't have much of a chance against cephalopods and are usually dead meat. However, against a large smasher - in the open - bet on the stomatopod."

Stomatopods can be prey of octopuses (as they are prey of large fishes etc --- life sucks sometimes no matter how well-armed you are) but I would wager that many octopuses and other cephalopods go down as dinner as well in the opposite direction...they're just way too soft and squishy to resist (grin)...
Yes this is interesting, and that is why I came back here to check this thread, this late at night.

I think soft and squishy might be an advantage, when it comes to a striking blow. Certainly, a stomatopod would have to land a direct hit, between the eyes, almost literally, to kill an octopus, before the octopuses beak punctured it's shell. I believe a stomatopod would eat a cephalopod, but not a very advanced one. Not an adult octopus, or cuttlefish.

Certainly molusks, and specificly cephalopods, are a major food source for sea predators, but we are mostly talking about small squid and bivlaves. Humbolt squid and Giant Pacific octopuses have been documented, on film, attacking divers. I'd much rather have my thumb smashed open than my mask ripped off at 100 feet. While a live giant squid has not been filmed alive, some believe they may actualy be the only predators of whales, besides mankind.


Oh, and evidence....

Why don't you ask Dr. Caldwell, or perhaps James B. Wood, about tests cephs have been put through. I'm sure you know the "unscrew the lid to get the food" trick.

This may be urban legend, but there is a story that goes something like this:

A guy had a pet octopus, and kept a feeder tank with crustaceans. He kept coming home to find less feeders, and blamed his roomate for feeding the octopus too much. This went on for months, and the roomate continued to deny feeding the octopus.

One morning, they found a wet smear on the wall between the octopus tank and the feeder tank. It had been feeding itself.

Another variation of this story is with biologists, where one of them witnesses the octopus returning to it's main tank, and CLOSING THE LID, so nobody would be the wiser.

Could be true, but I haven't seen anyone claim to be the real people.

yep, peace, it's sorta silly to be arguing too strongly about the who eats what theme...

Here's some thoughts on your comments above:

1. smashers don't just smash things...when they note that the prey item/ predator is soft (e.g. squid or octopus or a human hand), they STAB (the tip of their raptorial appendage is wickedly sharp) so it's like being confronted with a knife-wielding opponent who has a hammer at the same time...I once was stabbed by a small smasher and I can tell you the thing hurts (although it may have been part surprise)! A diver once tried to pick up a large smasher, got stabbed in the hand, and had to get it amputated later...Spearers also have sharp claws and have been known to slice a prey in half with one blow...

2. I do not believe the "unscrew the lid" proves much since it does not seem to be easy to replicate that action consistently and again other invertebrates seem to show similar patterns (although, since they don't have suction arms like octopus, opening a jar lid might be a bit difficult)...mantis shrimps, when presented with new shell types, at first fumble trying on how to "open" it (ie smash it open), but quickly (seem to) learn how to open it efficiently (eg by holding it a certain way and hitting it at a certain point). When later presented with similar shell types, they open these very fast using the new technique...might not this be similar to an octopus fumbling with a closed jar then later being able to open it much faster due to some learning?

3. Even if true, I am not sure whether the closing the lid trick allegedly played by octopus shows anything. An octopus tends to block the entrance hole of what it considers its home and this may simply be a manifestation of that tendency applied to the whole tank...again, we may have to be careful about assuming human motivations on actions by other animals...

4. I am also not sure what your point is about the humboldt squid...if there were smashers as big as these (6 ft?) I think they would be sinking boats (believing them to be large armored crustaceans), not piddling around with divers and their gear (grin)...
Mantis vs Octopus

Mantis vs Octopus

Just an anecdote on this heated subject. A local LFS owner, who I have trained to keep a few mantis in stock, told me this story. A small octopus( I saw him, he was pretty tiny) escaped over the barrier while he was working in the area and got in with a 4 inch mantis. He said he actually noticed it happening but before he could do anything, the mantis attacked and was promptly TORN IN HALF by the octopus. TWO PIECES. It was hard to believe when he showed me the small cephalopod, but he's a good guy with no reason to lie...
Whew! Thanks for all the posts! And I though my original post was such an innocent question.

Torn in half? wow! sounds like a hollywood movie. he was probably jerking you around. i found this page on octopuses (after seeing all the posts by fishroom) and octopuses wrap crabs and stuff in their tentacles, not tear them. Check it out.Its called the Cephalkopd pAGE...I forgot the link but will post it later.
Hi Reefer:

You are probably right about the way cephalopods attack...i have seen serveral pics of them (one killing a stomatopod) and in all cases they attack from above and wrap their arms around the prey...I am not sure whether their muscles are strong enough to easily tear in two a prey item as large as themselves or larger...maybe an octopus expert might be able to help clear this up...
For the record, there recently was a 4" Peacock Mantis killed by a hand sized Octopus at my LFS. They had each one in separate 5-6" cubes, with one cube separating them, you know the section that shrimp and individual critters are held in at an LFS. They came in one morning to find the Octopus had put it's tentacles thru the little holes used for cross flow, across the empty cube, threw the next set of holes into the Mantis's cube, and hand the Mantis all wrapped up and was slamming/yanking him against the wall. He was still alive when they got him, but died a short while later :( The previous day I had bought the smaller Peacock. needless to say, I was surprised.
no surprise

no surprise


that's nice.

no need to be any enclosed, tight situation, you can bet on the octopus coming out on top. it sometimes helps to be soft and squishy.

btw, this thread is OLD, and to be honest about it, who cares which critter can outfight the other..i thought we left the roman gladiatorial arenas awhile back. it all depends on the circumstances, anyways, and each critter has its own advantages and disadvantages. stomatopods (esp spearers) capture and eat cephalopods all the time), while other cephalopods engulf and eat stomatopods as well. that's just how it goes when you have two predators who happen to be hungry at the time.

each has its own detractors and supporters...

the mortality of shipping octopuses and keeping them is much higher than mantis shrimps, so in my opinion there's a moral high ground in staying away from keeping these cephalopods anyways. but to each his own. end of rant <g>
I'm not going to get into this except to say that all things are relative. Big octopus eat little stomatopods. Big stomatopods eat little octopus. When they are roughly the same size, it can be exciting. In fact, that is a line of research that I'm currently studying - interspecific competition for cavities. Throw in a few snapping shrimp and a goby or two and it gets really interesting.

Howard Hall shot a great piece of film a few years ago of an adult Hemisquilla ensigera taking on a large octopus. They were about the same size. I've seen octopus catch Hemisquilla in their burrows at night and kill them, but this octopus encountered the stomatopod during the day. The stomatopod didn't wait in its burrow, but launched a preemptive attack from a few feet away. It landed a couple of solid blows and the octopus beat a hasty retreat. Great sequence!