Saturday, July 4, 2009

Because you demanded it!: THE SEA PIG!! aka Scotoplanes globosa!!!

I was casually checking the numbers for the Echinoblog over a July 4th weekend in 2009 and on the day just before a 3 day weekend I found there was a HUGE spike of hits (>600 in one day!) simultaneously and inexplicably searching for something that I narrowed down to a massive international search for the term "sea pig".

Reasons were offered: A new Facebook quiz app. A video on Youtube. Who knows?

But if the PUBLIC wants to know what a SEA PIG is and I KNOW??? Then Frak it!! Its my duty to society to tell it WHAT a sea pig is!!! Who am I to deny the public's interest in sea pigs??

So, let's get to it!

What is a Sea Pig??
The "sea pig" is the common name (i.e. non-scientific name) for a species of sea cucumber (in the class Holothuroidea) that lives in the deepest abyssal depths of the world's oceans.
Specifically sea pigs belong to the genus Scotoplanes, a genus of deep-sea sea cucumber which currently includes four species. Sometimes other genera of deep-sea sea-cucumbers are called "sea pigs", but historically, THIS is the one most people mean. Its not entirely clear if those four species are all distinct, but THAT is a discussion for another day...
The name Scotoplanes has been around for a LONG time. The genus was discovered and described by H. Theel in 1882 as part of the famous HMS Challenger expedition reports. Sea pigs are ELASIOPODID sea cucumbers, an order of sea cucumbers whose members are prominent in the deep-sea.

They are often characterized by having these little legs that come off the bottom surface such as what you see here (legs on side, mouth pointing outwards)

One species, Scotoplanes globosa seems to be particularly widespread with a distribution that is WORLDWIDE. Yup. That's right you can find it in the Atlantic, the Pacific, in the Indian Ocean and of course..in the Southern Ocean (Antarctica).

Because waters in the Southern Ocean (Antarctica) are so cold, sea pigs can be found in shallower waters around the South Pole. Pictured here is one collected during the recent expedition operated by the New Zealanders and held by NIWA scientist (and friend of the Echinoblog) Sadie Mills:
(Photo credit: Richard O'Driscoll, NZ IPY-CAML)

How do Sea Pigs Live ???
Scotoplanes live in the ABYSS. That's not just a little deep..that's the DEEPEST part of the ocean on the flat oceanic plains. Its not unusual for sea pigs to be collected from over 6000 meters!!! How deep is that? That's about 3.7 miles DOWN (by contrast the Grand Canyon at its deepest point is only about 1.1 miles deep). Some can be found shallower..but they live across a wide bathymetric range.

Scotoplanes don't just occur individually either. Collections and observations of these animals show that they often number in the hundreds. Early trawling records have recorded some 300-600 specimens per trawl!!!
What do they do down there??
Very little is known about Scotoplanes general biology, but we do know a thing or two about their nutriton.

Like a lot of other deep-sea sea cucumbers, Sea pigs are what's called deposit or detrital feeders. That is, they feed on the fine nutritious scum and goo that falls to the bottom of the seafloor from the top of the ocean. They feed on them with the ring of tentacles that surrounds the mouth...
(This image from the Galathea 3 expedition site)

BUT contrary to some accounts that these are "slug like" or coarse dirt worms, deep-sea cukes like Scotoplanes have evolved this feeding mode into a finely honed adaptation!!

For instance, this study by Robert Miller et al. (2000) studied several deep-sea cuke species from the North Pacific, including Scotoplanes globosa using isotope tracers.

S. globosa (and other species in the region) ingests only VERY fresh (and presumably very rich) food-rich sediments. This species (and others like it) feed on a thin veneer of food that had settled out of the water column the last 100 days. So they actually eat FRESH food.

(from Gage & Tyler 1991)
Other facts of interest??

1. According to Dave Pawson, Smithsonian Curator of Echinoderms (and an expert in deep-sea sea cucumbers) you can also often see this species all oriented in a particular direction (such as above) facing into the current, where they are presumably rooting around, searching for better and fresher goo to eat

2. According to this study summarized by the Monterey Bay Aquarium Research Institue and performed by marine biologist Henry Ruhl, the food that these beasts eat (which as a reminder- live at THOUSANDS of METERS depth) ARE directly influenced by what comes down from the SURFACE of the ocean!! Yes, what happens at the SURFACE affects animals that live THREE MILES down!!!
There is apparently a direct correlation between some species and rich food that falls to the ocean fall following certain oceanographic phenomenon such as El Nino.
So, for example, the population numbers of S. globosa boomed after the rich nutritional particles descended folowing the 1997-1999 El Nino and La Nina periods. Ruhl also found other relationships between abundance and size (summarized here).

Scotoplanes have parasites!!!

a. Small snails (genus Stilapex) that work their way into the body wall and suck on their juices!! So, what's weirder then sea pigs??? SEA PIG SNAIL PARASITES!!!!
(from the New Zealand R/V Tangaroa weekly log, photo cred-Stefano Schiaparelli, NZ IPY-CAML)

b. Crustacean parasites!!
Good Grief!! It gets even worse then that!! Tiny tanaid crustaceans will also BORE little holes into the sea pig body wall and feed on the internal organs!!! Yikes!

(from the New Zealand R/V Tangaroa weekly log, photo credit-Stefano Schiaparelli, NZ IPY-CAML)

FINALLY..one of the neatest things I found out about sea pigs???

They have become SO iconic that A Japanese toy company (Agatsuma) makes small toys (about 1 inch long) of them!!!
Whew!! So, any OTHER questions about sea pigs????

68 comments:

hello there said...

Can people actually buy sea pigs? and where are the toys of them sold? also, can they survive in a tank as pets?

ChrisM said...

Nope. These animals live in thousands of meters of water. The temperature and pressure can't be duplicated at the surface without huge expense.

and even if you could, collecting them usually involves ships and/or submarines, which is why the only people who have ever seen them are usually marine biologists and oceanographers!

ChrisM said...

btw...the toys show up on ebay or are sold in Japan..

Hi! I'm Janola. said...

Wow. Wait, wait. I mean, "WWOOOWWWEEEEE!" That was so cool! I have known of them for a long time (probably as long as you have) but didn't know anything about their lifestyle.

Parasitic snails?? Hooray! Go, snails!

Jennifer Frazer said...

These guys remind me of naked mole rats or star-nosed moles. Convergent evolution strikes again!

Also, I don't know if food that clocks in at under 100 days old can be considered "FRESH". . . just my two cents. :)

Thanks for the intro -- absolutely fascinating!

Jennifer Frazer
theartfulamoeba.com

ChrisM said...

well...it IS marine detrital snow. 100 days is definitely fresh food when you consider how long it takes to sink 3.3 miles!

hello there said...

Ohh I see. Thank you. So they absolutely cannot survive on surface?

Anonymous said...

Somehow, I found your blog searching for information on cyclocystoids, and have stayed for the obvious reasons.

Humppe said...

Wow, thanks for the info.

And to answer your question at the beginning: I guess the huge interest in Sea Pigs was spawned by a Facebook app called "What terrifying creature are you?" in which Sea Pigs was one of the results.

Pete said...

What's the best way to cook them?

baltanray said...

i was gonna say... do seapigs taste like pork... or cucumber... or both?!

ChrisM said...

if you've ever had sea cucumber-that might be the best way to estimate flavor. But its unlikely that 99% of people will get a chance to ever try "sea pig" given that most times its scientists who will be collecting them.

cheetahmags said...

No, "hello there," any creatures living under such an immense pressure could not survive in our "world". It would be like humans trying to live in the deep sea without the protection of a machine or some sort of futuristic pressure protection suit. Any deep sea creatures brought to the surface die instantly.

cheetahmags said...

Also, I thought your info on the sea pig was great! :D

Anonymous said...

Do they have any predators or prey?

ChrisM said...

They probably do. Possibly fish or sea stars. But I don't think its ever been really been documented. Ecology in the Abyssal zone is difficult..

Jennifer said...

I found out about Sea Pigs because of the Wii game "Endless Ocean" and thought they were made up! Thanks for posting such great information about them - the photos are great!

ChrisM said...

Search the Echinoblog for Scotoplanes or "sea pig" and you should get a few other posts as well. There was a nice slow- mo video of a sea pig I posted awhile a month ago or so.

Wonderful Sam said...

I was introduced to sea pigs two days ago at during a visit to the Smithsonian Museum of Natural History, and they have been creeping me out ever since then. They are fascinating. And creepy. Thanks for all the great info. Fascinating stuff!

ChrisM said...

Well, the Smithsonian is near and dear to my heart! I'm always glad to hear that people are learning about sea pigs there! thanks!

Jhadur said...

Awesome! Any idea how far they can roam? And if they form social groups or herds of some kind?

ChrisM said...

I don't believe that anyone's ever determined how far they roam or if they form social groups. Often times, their numbers are interpreted as a constraint on where they settle as larvae and food availability..since good deep-sea food is often difficult to locate.

Raymond-Maurice, Freiherr van Pottelbergh said...

Very informative. But may I ask if Scotoplanes have genders. How do they reproduce? Also another blog mentioned that they enjoy the rich ooze surrounding decaying whale remains. Is it known which organisms are primarily responsible for breaking down whale tissue into nutrients that Scotoplanes can use?

ChrisM said...

Raymond-Maurice,
My understanding is that sea pigs have two sexes (most if not all sea cucumbers do-but I will check).

In general, sea cucumbers reproduce externally. That is the males and females secrete their gonads into the water. The sperm and the eggs then find one another-probably using some kind of chemoreception facilitated by behavior (i.e, the dense aggeregations), fertilize and then settle out. Probably based on some optimal environmental cue based on substrate, food or some other essential need.

As a generality, Scotoplanes would consume freshly deposited nutrients wherever they occurred. I don't know exactly which blog you are referring to.. but presumably such a site would be a good place for sea pigs to incidentally find food (i.e., because they are drawn to nutrients in the sediment or in the water)..but-to my knowledge-is not one of the primary or even a significant player in a "whale ecology" type system. It may feed on surrounding detritus and/or nutrients in the surrounding sediment..but my understanding is that sea pigs consume relatively fine material..and as far as I know-don't eat flesh or particles of meat off bone.

hope that helps!

Anonymous said...

This is really cool! I'm doing a science project on some of the weirdest creatures on Earth, and the sea pig is defidently one of them. I got here from the Animal Planet website.

ChrisM said...

dont' forget this post about pearlfish

http://echinoblog.blogspot.com/2010/05/when-fish-live-in-your-cloaca-how-anal.html

or this one about giant brittle stars that capture fish.
http://echinoblog.blogspot.com/2008/11/giant-green-brittle-stars-of-death-when.html

and don't forget Gorgonocephalus
http://echinoblog.blogspot.com/2010/01/gorgonocephalus-because-weird-is-what.html

JessBaby18 said...

OMG! I am doing a science report. This site has really hepled me. Thank you.

By the way, this creature is cool yet scary.

Ethan said...

Hey there, i am doing an assignment for school and decided to do some research on sea pigs. Would i be able to use your information for my work? This included both pictures and text. Please email me for confirmation at ethan.murray93@hotmail.com,
thanks.

ChrisM said...

you can use the blog (as long as its cited) but there are several scientific references linked within the blog that will likely be of more use.

you don't say which level of school-but so long as you don't plagarize my work using it as a resource is fine.

Laura said...

hey there

what about the sea pigs over grazing and forest management in the ocean and the limiting factor and carrying capacity of it as well. Do you know anything about that?

Anonymous said...

I LOVE SEA PIGS SO MUCH I HAVE BEEN OBSESSED WITH THEM FOR 2 YEARS!!!

Anonymous said...

I LOVE SEA PIGS!!!!!!!!!!!!!!!!!!!!

Anonymous said...

i was wondering what did sea pigs evolve from?
FANTASTIC website by the way!

ChrisM said...

What did sea pigs evolve from? hmm... good question..
Of course, they are sea cucumbers but I'm not sure where in the grand scheme of sea cucumber evolution they fit...

I'll have a look...

Anonymous said...

Do you know how big they are?

ChrisM said...

They don't really get very large. One of the photos shows one being held in the hand of a scientist. That's about typical (about 4 to 6 inches) (about 10 to 15 cm).

Unknown said...

I now love sea pigs so very much!etattod

Ohaithere said...

I think that you should also post about the pistol shrimp, they seem pretty amazing themselves...

Anonymous said...

Thanks for the info and the nice blog. I am nowhere near an ocean but I am just interested in sea pigs. I think they are cute. I wish I can have one as an aquarium pet

Erica / Northwest Edible Life said...

Thanks for this excellent explanation.

Anonymous said...

I'm curious about the differences in the illustrations of the sea pigs. The pictures of them on the ocean floor show thinner sea pigs with longer legs. Those in the air are rounder with short legs.

Are these two varieties of sea pig, or is this what happens when the sea pressure is taken away?

ChrisM said...

The difference in appearance is probably attributable to a few things

1. The deep-sea vs. the Antarctic pix are of different species and so, yes, the legs and proportions do differ between them.

2. Most sea cucumbers will swell with water when stressed and to me that seems like the most likely explanation here. Its possible that gas is responsible for the swelling in the out-of-water pictures but I don't believe there is a place for the gas to build up other than the intestine-as there are no gas bladders to become swollen as there would be in fish.

Anonymous said...

Hi! Sorry, I don't have blogger account, so I'm anonymous. Do you think it's not plausible for them to get bigger than 4 inches? Like calamari get huge.
When it dies, does the body stay on the bottom of the ocean?
I've seen something gross that looked exactly like a sea pig, but dark coloured and big, on the tide line in Vancouver, Canada. It smelled really bad too. I thought it was probably elk/ cow carcass (or some other mammal) that was missing head and legs, but the skin looked smooth and shiny. It looked really gross! You couldn't tell what it was, but it looked like something!
Even if they do get big and can get to the surface, it seems unlikely for them to surface on Vancouver beach, as there is Vancouver island that separates open ocean from Vancouver.

ChrisM said...

Sea pigs and their relatives generally don't get very large for several reasons-most likely having to do with metabolism and a multitude of other factors. Some sea cucumbers in tropical habitats can get very big up to 1-2 feet long but most deep-sea sea cucumbers are in the 4 to 9 inch range depending on species and where they live. Where food is more abundant some species may thrive. Some Antarctic species for example can get to be almost 8 to 9 inches long.

That said, what goes on for sea cucumber is different than what goes on for cephalopods. Giant squids (Architeuthis dux) are a separate species and indeed a separate family than other squids and a different evolutionary history has likely been at play. This includes the fact that squids are predatory swimmers, live in a different habitat (the midwater versus the bottoms) and so on. "Giant" is also relative...but there are no known sea cucumbers that reach greater than about 2 feet long and those tend to occur in tropical reef type habitats.

When sea cucumbers die, they pretty much disintegrate immediately and are either devoured by scavengers or are buried. Its unlikely that anything from this depth (2000 m or so) would reach the surface. If you saw anything at the surface that was a dead sea cucumber it was probably a local species and not a deep-water sea pig.

hope that helps.

Anonymous said...

Thank you for the explanation!
I'm obsessed with these sea pigs now. :)) Round ones look so cute.

Anonymous said...

Do we know how old this species is? It looks pretty prehistoric and if a ceolocanth can survive to this day and age, I wouldn't be surprised about the geneology of this strangely facinating creature.

ChrisM said...

Well, one has to keep all of these things in context. The coelacanth is considered a "living fossil" because its outward appearance closely resembles that of fossil taxa but, actually a great MANY modern animal species are descendants of those which are very old. The lineages of nearly all echinoderms dates back to the Paleozoic.

Sea pigs are elasiopod sea cucumbers, a group which, I believe have a fossil record from the Mesozoic but I don't know if there are complete body fossils-only remains.

The specific evolutionary history of this specific *species* and its ancestor could be quite young but part of an older lineage. But even that is relative. Some species may be less than 20,000 years old but others may be more on the scale of 1 to 3 million which is still considered quite young compared to others.

I have been meaning to publish a little more on the evolutionary history of this or possibly other sea cucumbers so we shall see. There is not as much known about its history as we would like especially given its relationship to the deep-sea.

ChrisM said...

...and by publish I mean on the blog. Sadly, I don't work on sea cucumbers myself. :-)

Anonymous said...

Hi I really loved this and I think it's really great of you to make a blog about something that not most people talk about. I get soooo annoyed when people talk about the more common animals. Anyway, I'm doing a project on Sea Pigs at school and one of the questions is," What adjustments are needed to survive in the environment?" I've looked all over the internet and found nothing. Do you think you could help?? If you could, that would be soooooo nice of you!!

ChrisM said...

Glad you liked it. I published this blog post shortly afterwards that is relevant.. http://echinoblog.blogspot.com/2009/08/why-sea-pigs-and-other-deep-sea-animals.html

onechordbassist said...

Usually echinoderms will not develop a centralised nervous system due to their pentaradial symmetry and their ability to move in any direction equally. However, these animals have not only developed a secondary bilateral symmetry, but also a direction of movement, so I'd like to know if there are any hints of nervous centralisation in Scotoplanes, especially considering they have legs.

ChrisM said...

@onechordbassist That is an excellent question. The nervous system of deep-sea sea-cucumbers such as a sea pig are poorly known but if they are typical for sea cucumbers (and there is no immediate reason to suspect that they are not dramatically different) the nervous system forms a ring around the oral opening which is connected to nerve fibers running down the length of the body.

Sea cucumbers have a secondary bilateral symmetry imposed over their pentameral symmetry that is associated with their movement through sediment. It is centralized around the front end in the aforementioned nerve ring but there are no known enlarged ganglia or nervous centralizations that I am aware of, but there's a lot of information about these animals which remains unknown or poorly understood.

Anonymous said...

do sea pigs go through life stages?

ChrisM said...

The life cycle of sea pigs is poorly understood but all sea cucumbers undergo some change from larvae to juvenile and then growth to adult. Every new or poorly understood species has the potential for some new life cycle or other undiscovered fact about their reproductive cycle so we shall see...

Anonymous said...

BTW -- Another great source for deep sea items, toys and plushes is ETSY.com. There are a couple cool artists that make deep sea sculptures, knitted critters, stained glass, stoneware, and christmas tree ornaments! Our favorite artist there has made plush deep sea anglerfish and monkfish for us. Next on the horizon: Lasiognathus, Prince Axel's Wonderfish (Thaumatichthys Axeli)...and SEA PIG. I can't think of any better bed time buddies for confirmed nerds. :)

Anonymous said...

What is a sea pigs support structure, respiration, circulation, excretion, response, and how does it reproduce

ChrisM said...

To answer your question:
support structure, respiration, circulation, excretion:-Water.

response to what?

they reproduce, presumably by external fertilization. Eggs and sperm in the water=larvae. the larvae settle. boom. there ya' go.

Anonymous said...

How do sea pigs breath?

ChrisM said...

Most sea cucumbers have respiratory organs that are connected to the intestine. However, deep-sea cucumbers such as sea pigs lack these organs and can exchange gases across the body surface. They absorb oxygen across the feet and other surfaces on their body.

Knox said...

I'm afraid my English is a bit rusty...
I just stumbled upon this article in search of echinoderms.
I read about sea pigs before, but this was by far the most extensive article about these animals. Because of this excitation of my curiosity I am going to make some additional inquiries about them. I just wanted to thank you for this motivating article.

Anonymous said...

how do sea pigs adapt to the depth of the ocean?

ChrisM said...

The question "How do sea pigs adapt to the depths of the ocean" might be better re-stated as "How have sea pigs changed relative to their (presumably) shallow-water ancestors?" In other words how have their body forms been modified by the environment over time.

Deep-sea sea cucumbers such as sea pigs have much larger tube feet which have become modified into the walking "legs" and there are several differences in the physiology of the animals relative to depth and probably to temperature. Many deep-sea species also do not eviscerate (eject their guts as a defense).

At the moment, I don't really have access to the research literature due to the govt. shutdown but I hope that gives you at least some idea..

Anonymous said...

thanks for ansewering my question, just another one how has their bodys adapt to the temperature of the deep ocean?

Anonymous said...

does sea pigs are safe to eat ?

ChrisM said...

I would avoid eating sea pigs

Skymouse said...

Hello thanks so much for the information about sea pigs. My little boy (4) was fascinated after seeing this episode of octonauts http://www.youtube.com/watch?v=WlFvg5N_XTY&sns=em. Maybe this was the reason for the sudden influx of sea pig queries?

The episode suggests they eat rotting food (kelp) as opposed to what your blog says about a preference for fresher food. Thanks again!

ChrisM said...

Skymouse,
*laugh* OH WOW! thank you! While you are correct that sea pigs enjoy fresh food, dead kelp does make up part of that as it falls to the sea floor. It all kind of relative.

Anonymous said...

what do they eat