An introduction to cephalopods (octopus, cuttlefish and squid)
Dr. James B. Wood is a marine biologist and professional underwater photographer. All marine invertebrates fascinate him but cephalopods are his favorites. James has kept aquatic animals since he was four; he captured and kept his first octopus while in high school. He publishes scientific work but also makes time to write popular articles and web sites and give presentations to museums, aquariums and clubs. James is currently working on CephBase - http://www.cephbase.utmb.edu/ at the National Resource Center for Cephalopods - http://www.nrcc.utmb.edu/ at the University of Texas Medical Branch in Galveston, Texas.
If you wish to read more information on Dr. Wood, please see: http://is.dal.ca/~ceph/JWood/cv.html
For more information on cephalopods, see:
- The Cephalopod Page: http://is.dal.ca/~ceph/TCP/
- CephBase: http://www.cephbase.utmb.edu/
A Powerpoint Presentation of this talk can be viewed here.
Cephalopods are NOT aliens, but it makes some sense if you image that they are Like any good alien, all cephalopods are predators. They are strange - they have three hearts that pump light blue blood They have a life cycle that is different than a mammals - most die after reproducing once Like an alien, they have special powers - Cephalopods can change shape, texture and color! They can regenerate lost limbs. A good alien has advances senses - so do cephalopods.
Of course cephalopods are not aliens but it is often useful for hobbiests to think of them as if they were. Why? Well, most of the animals that you are familure with. . . cats, dogs, fish - all are vertebrates, and have some similiar patters - especially the mammals Cephalopods are often different and this is important to keep in mind as it affects their husbandry.
Cephalopods are Molluscs - relatives of clams, snails, slugs, etc Other molluscs include. . . Bivalves, Gastropods, Scaphopods and Polyplacophorans. . . animlas that generally don't have a lot of neurons. Some of these animals don't even have a head! The one claim to fame they do have (most anyway) - is heavy armor When most mollusks are faced with a predator the simply clam up.
Cephalopods are naked! They do not have this external armor (with the exception of a few living fossils - the Nautilus) What they do have is a lot of tricks. The tricks that they have are what make them so interesting to me. In order to keep them, I feel that it is important to understand them Much of this talk will be on their biology, I'll also mention broadly the types of cephalopods as well as some specific ones that I like to keep.
Cephs evolved from externally shelled (tank like) molluscan ancestors. There was a time when this class was very dominant in the worlds oceans. The ammonites and nautiluses - both externally shelled were quite common. We think that the appearance of fish was one of the main reasons for the decline in the class. Modern cephalopods tend to have internalized, reduced or in the case of octopuses, no shell at all The race for the best body armor was over - now it is all about being fast and not being noticed.
ok technically thse famous eight appendages are arms An octopus, squid and cuttlefish all have eight of them Squid and cuttlefish also have two tentacles - these they shoot out to capture prey. The tentacles are much longer than the arms and only have suckers on the ends The sac like part is the mantle It holds the animals organs The head is much smaller and is right between the eyes.
cephalopods are amazing at what they can do with color, shape and texture. All of this in neuarally controlled so it is VERY fast. The male is smooth and has zebra stripes while the female is brown and fuzzy as if she is covered with algae. Even the developing octopuses in their eggs and newly hatched octopues are well formed and have chroimatophores, The cells they use to change color
So, these animals hatch out very large and advanced That ***should*** make them idea animals for aquaculture. Actually, we have raised cuttlefish for over 14 generations in the log For what ever reason, home aquarists have not had good luck with ceph propogation - maybe that will change soon!
Most of it is has no suckers - the arms of the octopus below have suckers from their tips to theri base at the animals mouth Suckers can grip strongly and can taste. So these animals get a lot of information when they grab onto things. Each sucker has it's own CPU - Errrr ganglia of nerves.
Most molluscs have an innefficient open closed circulatory system. This works just fine for them - after all, how often do you see a Tridacna clam chasing down a crab that is bigger than it is? Cephs have a closed circ system - much like ours. It is a high pressure efficient system. And it delivers blue (copper based) blood to the animals tissues. The BEAK is at the base of the arms - avoid it. Cephs are well adapted to grow like weeds - that means they eat a lot The have a protein metabolism so they produce about 3 times the amount of nitrogen waste as a fish thier weight would - something to keep in mind when setting up your filtration. Like us, they have seperate sexes
So, you are already thinking about BREEDING them - good. . . Keep in mind that they can be cannibalistic (spelling?) - Some species much more than others. Sexing them is um. . . FUN he he he You look for the third right arm on males - which arm is the third right? In a living active octo - it is just best to pick any arm and work your way around looking at all of the arms. What you are looking for is a small organ at the end of the arm - this is used to transfer spermatophores to females. Shallow water octopuses won;t be anywhere near as well endowed. . . :-)
These animals have well developed senses and to process all the incoming info. . . they have well developed nervous systems. The word 'brain" is not usually used with invertebrates but in this case, it applies. These animals have distinct lobes in their brains. However, unlike us, most of their nerves are in their body! They have larger brain to body weight ratios than many fish and reptiles
How smart an octopus is can be a tricky question - we still don;t have an IQ test for humans that everyone agrees on But there are two analogys I like to use to talk about ceph intelligence I have a really big fat wallet, it is full of reciepts, cupons, lists, change, - in other words there isn;t a lot of value in there. So a large brain doesn;t by itself mean an animal is smart. On the other hand - biologists like to say "form fits function" A rabbit has good muscels in it's hind legs for a reason We do know that cephs are capable of some advanced behavior. . . We know that octopuses can learn very quickly But they do not retain what the learn as well as a mouse would (they make more mistakes) There are (somewaht contriversial) papers on tool use, observational learning and play in octopuses. The bottom line is, for an invert, they are quite advanced. And they WILL use their smarts to get out of and/or redecorate your tank!
One of the most amazing things in the biological world is not the human eye or the cephalopod eye But the fact that the two are designed almost totally the same They don;t see in color but can detect differences in polarized light and their eyes work well in low light Handy as the light bouncing off a silvery fish becomes polarized And these animals are mostly nocturnal They have a lateral line system like fish Balance, smell, etc I think their sense of touch and taste is better than we generally think but vision studies have had more attention
OK folks - this is very important if you want to keep them. . . They do NOT live long! If you purchase a medium sized octopus it might already be mature and might die 2 months later. Or, if female, might lay fertile eggs two months later! From egg to death is usually a year for cephalopods Even the giant pacific octopus lives for about 3 years. Small warm water species have even shorter life spans than a year. If you doubled your weight every two weeks Just think how BIG you would be! And how much you would have to eat! Acquiring enough quality food is often the pitfall of home aquarists who try to rear cephs. The hatchlings need live food - amphipods, mysid shrimp, crab zoea, etc Artemia do not work well
Semelparity = Reproduce once and die The life history pattern for many cephalopods Sounds odd doens't it? But samon, cicadas, century plants all do this too. Cephalopods share a motto with the Hell's Angels - Live fast and die young. Most molluscs, and many marine animals, have millions of offspring. And often these tiny offspring look nothing like their parents The offspring of molluscs - trocophores and veliger stages - look like space ships - not at all like baby clams Cephs all have larger and better developed offspring. This makes them easier to rear than most animals
The different types of cephs are: Nautilus, squid, cuttlefish, Sepiolids (small cuttelfish like animals) My favorite, octopuses. Also there are Vampire Squid and Spirulida but no one is going th have THOSE in a home aquarium These guys are the exception They are living fossils - externally shelled, slow growing There status in the wild is uncertain and only 2 or 3 places in the world havve hatched them form eggs laid in captivity. No one has raised them from a hatchling to maturity yet. They might be overfished. . . And while their shells are very nice, they really don;t do much They are pretty much a swimming snail Squid (like James W) are hyper Unlike James, they tend to spaz when immersed in water and any littlke thing happens The lights turn on - AHHHHHH! Jump out of the tank, smash into the walls, etc This is for BIG research tanks so they would be even worse at home Cuttlefish and Sepiolids are much better choices And some of them aren't so hard to raise form eggs Finding a source of live cuttlefish can be a challenge . . .
Octopus - my favorite No shell Can get out of anything - actully this depoends on the individual and species - some ar emore escape prone than others. CephBase is what I'm working on now at the National Resource Center for Cephalopods There is a lot of info in the database. Some data that you might be interested in are: Distribution of various species And what they eat in the wild The ceph page is. . . chaos It has been helping aquarists since 1995 and has grown out of control! There a many artilces on this page - including several on keeping octopuses and cuttlefish. Feel free to check it out
if you wanted to keep Octopus briareus what would you feed it? And could you ever hope to keep snails with it?
LOL Mine never ate snail until I told Roy Caldwell that they didn;t eat snails - then they of course started eating them! Like me, octopuses like crustaceans. Shrimp, crabs, etc The BEST food is live marine crustaceans and I would advise that you feed a new octopus these FW crayfish are a close second And once your octo knows you, frozen food (fish, crustaceans, etc) is easiest.
What would you feed a 2-3" joubinis octopus? It seems hes eating snails and maybe small hermits? what can I feed that is a cheaper/quality substitute?and what is an acceptable way to offer the food, just put in a live crab and let him find it, or some how get it in front of him?
Hmmm These octopuses often hide A LOT Which makes it hard to try the frozen
food on a skewer trick You could try to touch it to him and see if he grabs
it - sometimes they just get scarred though
what are the physical characteristics of the vampire squid?
They are deep-sea and there is only one species in the order, The tree of life is quite good for taxonomic descriptions The link says it better than I could here. :-)
what is the lifespan of a nautilus in a home aquarium?
Hmmm I don't really have the statistics on that They seem to live for a while - at least in the cases I know about We never had to many problems with them. However, they are collected for their shells and they are slow growing And don't produce that many offspring (12 or so a year) Also, they don;t DO much so I don;t reccomend them
if cephs can't see in color, how is it that they are able to match things so perfectly?
That is a very good question! For one thing, there are not patches of hot pink so some colors we can rule out Also, they can reflect som of the surrounding color and this helps them match the color even though they are not seeing it Most of the combinations of yellow, red, brown and blacks that they can do match most thing sin the environmnet But if you put one on hot pink and yellow rocks - especially if both colors are the same grey scale - they will stand out! That is about as good of an anser as I can give to that one!
how possible is it to establish and maintain a successful cuttle fish home aquarium and what is the availabitly of these creatures and there specific life span?
Lifesapn depends on species S. officinalis lives 18 months S. pharaonis live 9 months or so Both are about the same size but S. pharaonis lives in much warmer water Availibility IS a problem! For cephs in general and esp for cuttles Every source I know about that ships is listed at: CEPHS To raise them you would want some large tanks - ours are fiberglass and you can swim in them - yours don;t have to be THAT big.
what water temps do the nautilus prefer?
16 C would be good - they live fairly deep
I see that you are in the Medical Division of the University of Texas. What, if any, is the application of cephalopods to medical research?
Squid are fast, and have a very large nerve - which makes it easy to study how it works Also, the ink is the purest form of melanin (the stuff in your skin) in the animal kingdom And this is used for anti cancer studies Their retinas are used. . . They are used as models of non vertebrate intelligence