Top Five Ocean Creatures You've ACTUALLY Never Heard Of

Okay internet, we've got to talk. Yes, the ocean is incredibly vast and minimally explored. There are many creatures out there that people have never heard of, and I'm really excited that you want to share the ones you just discovered with humanity. But friend, most other people have also watched Planet Earth. You can't go around publishing listicles of the animals from the deep sea episode and call it "Top 10 Ocean Creatures You've Never Heard of!" or some such thing. We've all heard of blobfish; flapjack octopuses inspired a character in Finding Nemo; and literally everyone knows about Mola mola. So for those of you who are tired of the same list getting republished on 30 different blogs with slightly different descriptions Depth and Taxa Presents our first ever listicle:

Top FiveOcean Creatures You've Actually Never Heard of!

Or: 

Top Five Ocean Creatures That Aren't Horrifying, Just Well Adapted to Their Environmental Conditions.

Seven-Arm Octopus (Haliphron atlanticus)

Courtesy: H.J.T Hoving and S.H.D. Haddock via Scientific Reports

Okay wait, wait, wait; seven-arm, octo-pus; that literally makes no sense. Why isn't it a septapus? To understand we need a refresher on our old friends, the Argonauts.

No....not....ugh...
Courtesy: Public Domain via Wikimedia Commons

If you've been following Depth and Taxa for a while you might remember our profile on the specialized octopuses called argonauts. You can check out that post (which is a personal favorite of the D&T team) here. Argonauts and their close relatives are different from more familiar octopuses because they live in open water, rather than on the bottom; and because males are waaay smaller than females. In the case of seven-arm octopuses, females are six times longer than males! The enormity of the open sea and the males' small size mean that the odds of two seven-arm octopuses running into one another are pretty low. So in order to ensure the continuation of the species males have to be sure they mate successfully on the first try. To that end, males actually tear off a specialized reproductive arm called a hectocotylus (pronounced: hek-toh-kot-uh-luss) and embed it into the body of the female. Since seven-arm males only get to use their hectocotylus once they keep it well protected inside a "thick, gelatinous" sack near their right eye. Because that arm is tucked out of sight, it looks like male seven-arm octopuses really only have seven arms.

Eulachon (Thaleichthys pacificus)

Courtesy: James Crippen via Wikimedia Commons

Yeah, it's a bait fish; but take a second to think about how many bait fish species you can name. Maybe herring, anchovy, sardine, and...... anything else? Also called forage fish; small fish like eulachon (pronounced: yoo-la-kon) are the only reason we have bigger, more charismatic animals in the ocean. Tuna, sharks, salmon, humpback whales, dolphins, seals, sea lions, pretty much anything larger than one foot wouldn't exist without forage fish like eulachon. Just because something is common, doesn't mean it's not important or interesting. In fact, forage fish are probably waaaaaay more important to the overall ecology of the ocean than many of the creatures we get really stoked about.

Eulachon in particular are really awesome. Like tiny salmon, eulachon are born in freshwater and migrate out to the ocean where they spend 2-3 years growing rich off the abundance of the open sea. And boy they get rich, eulachon have a higher body fat percentage than almost any other fish species. Eighteen to twenty percent of a eulachon's wet weight is oil! They're so greasy that if you dry a eulachon you can actually set it on fire; leading to their other common name: candlefish.

In case the plug-in doesn't work on your device:
https://www.youtube.com/watch?v=wEMQujyzHQA

The people processing the eulachon in the above video are members the Nisga'a first nation. Nisga'a territory is the watershed of the Nass river near the Alaska panhandle's southern border with British Columbia. Because eulachon come back to their home rivers to spawn in late winter when other food sources are scarce they can tide-over a family until the abundance of spring. Eulachon are so important that one of their names in Nisga'a means "savior fish". Not bad for a type of smelt.

Brachiopods (phylum Brachiopoda)

Courtesy: Peter Grobe via Flickr

"Alright wait a minute, that's literally just a clam. You can't pull one over on me. I've been to Ivar's." Well they look a lot like clams, but aside from both having two shells, brachiopods (pronounced: brak-ee-oh-pods) and clams are completely different.

Even the shells of clams and brachiopods aren't the same. The shells of a clam are oriented left and right of its body, while a brachiopod's shells are above and below. It can be a little hard to visualize without pictures so we'll use some anatomical standards to help us: Pokemon.

Shellder has shells oriented like a brachiopod. 
Cloyster has shells oriented like a clam.

Of course we all know it's what's on the inside that counts. Once inside a brachiopod the difference from clams is pretty apparent. Fully two-thirds of a brachipod's body is taken up by a feeding structure called a lophophore (pronounced: lo-fo-for). The lophophore has spiral or u-shaped coils that are unique to each species. These structures funnel free-floating plants and animals into the brachiopod's mouth using little cellular hairs that beat back and forth.

Brachiopods have been around for a long time and at one point there were at least twelve-thousand different species! That number makes a little more sense when you remember that brachipod is a phylum, which is one of the least specific ways to group organisms. For example: humans are part of the "chordate" phylum which is everything on earth with a spinal chord. That's a bewildering number of animals. Even understanding that they're a big group, it's astonishing to realize that brachiopods were once so abundant that make up the majority of all fossils!

There are only about 450 modern species of brachiopods, but they're pretty common in cold seas around the world. Very few animals eat them, even though they have thin shells, probably because brachiopods don't pack a lot of nutritional punch once you get them open. So the next time you feel lame for being unassuming and quiet; remember that brachiopods literally took over the world for millions of years by being mundane.

Pink Ghost Shrimp (Neotrypaea californiensis)

The larger pincher is called the "master claw", which is also 
a kickass name for a metal band.
Courtesy: Ken-ichi Ueda via Flickr

Pink ghost shrimp are just one of many species of shrimps that burrow into sand and mud in the intertidal zone. Although you probably haven't seen the actual shrimp there's a decent chance you've seen one of their burrows. These shrimps' extensive burrow systems have multiple entrances that allow water to flow through when the tide is in. You can easily find the entrances because the of the mounds of darker colored sand around the hole. The material from underground is usually dark gray or black because the low oxygen conditions within the muck stain the sand. Areas with low oxygen may sound like a terrible place to live, but pink ghost shrimp can survive for six days in those conditions! And if the oxygen gets too low ghost shrimp can be seen standing at the entrance to their burrows flushing in new water using the swimmerettes on their tail.

Ghost shrimp aren't just cool because they can survive without the chemical that literally makes complex life possible; they're also a major consumer of extra nutrients that get into estuaries. So much so that ghost shrimp might actually be the key to minimizing the damage human organic waste (fertilizers and more) does on the ocean. 

Even if you're not into crustaceans there's a good reason to love ghost shrimp.

"Whale, hello there!"
Courtesy: Linda Tanner via Flickr 

Ghost shrimp are the main source of food for gray whales as they travel back and forth from Mexico to Alaska every year. The whales dive down, suck up giant chunks of mud, and filter out the shrimp with their sturdy baleen. At low tide in Puget Sound near the mouths of rivers you can actually go and stand in pits dug by gray whales foraging for ghost shrimp. Who would have thought you would have a goop dwelling shrimp to thank for your Facebook profile picture of you in San Ignacio with the baby gray whale.

Leather Limpet (Onchidella borealis)

Courtesy:  Minette Layne via Flickr

First off, leather limpets are one of those rare molluscks that are freaking adorable. Seriously they're so tiny and they have goofy little faces!

If people can think sloths are cute they can definitely love this derpy little fella
Courtesy alex_bairstow via iNaturalist

Confusingly, leather limpets are not limpets at all. True limpets have a tent or volcano like shell on their back that they can raise and lower to protect themselves. Leather limpets have no shell to speak of, just a tough coating of tissue on their back. These little dudes also don't have gills to breathe in the water, they have a lung!

 Leather limpets avoid drowning by trapping a bubble of air in an opening above their butt. The opening is kind of like your nostrils and windpipe, so they're basically holding their breath while underwater. Land slugs have a system like this too. If you've ever looked closely at a slug you'll see a hole on what you can think of as their right shoulder. Pictures here.

Instead of hiding when the tide is low and crawling about when it comes back in; leather limpets' lung allows them to do the opposite. By moving around when the tide is out, leather limpets guarantee their predators will be firmly ensconced between rocks or in the sand. In case predators like sea stars do come calling while a leather limpet is hiding at high tide they have an effective defense. The little bumps on the leather limpet's side side secrete a fluid that repels sea stars and probably crabs.

Bristling like a teeny, squishy hedgehog.
Courtesy: paul_norwood via iNaturalist

So there you have it. Five ocean creatures you've probably never heard of. To be honest this list could have been thousands of animals long. The ocean makes up 99% of the habitable space on earth! It's deep, vast, and at the same time contains millions of tiny microhabitats. But there's one thing I hope you take away from this post. Look back at all the animals listed. How many of them are super rare? How many are a deep sea species that's only been seen a few times? And how many live in the waters or shore just down the road? Only one of these creatures isn't found in the intertidal zone. So what I hope everyone understands is that our planet, and even our immediate neighborhood, is incredibly rich. That you don't have to have access to high technology and millions in funding to explore and discover incredible things.

So get out there! Walk the beach. Poke around in the sand and mud. Lift rocks; peer on their undersides. And share your discoveries with us in the comments!

P.S. If you like this style of short, digestible information we do a similar segment called: "Wow Cool! of the Week" on our Facebook page every Wednesday. Check us out, and if you like what you see give us a like and a follow @depthandtaxa.
https://www.facebook.com/depthandtaxa/?ref=br_rs

References:

Cowles, David, "Onchidella borealis", Invertebrates of the Salish Sea (Online), Walla Walla University, 2007
Accessed via:
https://inverts.wallawalla.edu/Mollusca/Gastropoda/Gymnomorpha/Order_Onchidiacea/Onchidella_borealis.html

Cowles, David, "Neotrypaea californiensis", Invertebrates of the Salish Sea (Online), Walla Walla University, 2007
Accessed via:
https://inverts.wallawalla.edu/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/Eucarida/Decapoda/Thalassinidea/Neotrypaea_californiensis.html

DeWitt, T H., "Response of Ghost Shrimp (Neotrypaea californiensis) Bioturbation to Organic Matter Enrichment of Estuarine Intertidal Sediments", Presented at 27th Annual Meeting of Pacific Estuarine Research Society, Port Townsend, WA, May 17-18, 2004
Accessed via: https://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryID=81528

MacKinnon, J.B. "'Salvation Fish' That Sustained Native People Now Needs Saving", National Geographic Online, July 7th 2015
Accessed via:
https://news.nationalgeographic.com/2015/07/150707-salvation-fish-canada-first-nations-animals-conservation-world/

Pruitt, Casey & Donaghue, Cindy, "Ghost Shrimp and Gray Whale Feeding: North Puget Sound, Washington", Washington State Department of Natural Resources Report, October 28th 2016
Accessed via: https://www.dnr.wa.gov/publications/aqr_aamt_shrimp_whale_study_2015.pdf

National Marine Fisheries Service, West Coast Region, "Endangered Species Act Recovery Plan for the Southern Distinct Population Segment of Eulachon (Thaleicthys pacificus)", 2017

Accessed via:

http://www.westcoast.fisheries.noaa.gov/publications/protected_species/other/eulachon/final_eulachon_recovery_plan_09-06-2017-accessible.pdf   

Wright, J. 2014. "Brachiopoda" (On-line), Animal Diversity Web, May 21, 2018
Accessed via: http://animaldiversity.org/accounts/Brachiopoda/

Young, Richard E., "Haliphron atlanticus", Tree of Life Web Project, 2016

Accessed via: http://tolweb.org/Haliphron_atlanticus/20200

Mom! They're Copying Me!

The old saying goes: "Don't pretend to be something you're not." It's great advice for humans trying to navigate the complexities of identity and our place in society.

I'm lookin' at you, High School Me!

However, if you're a small creature that's constantly at risk of being eaten, pretending to be something else might not be so bad. 

There's familiar examples of passive camouflage everywhere in the ocean. Sea Dragons look like loose, floating kelp; stonefish lie as unmoving as their namesakes on the bottom; grunt sculpins are nearly indistinguishable from a barnacle when they're still. There are even animals that actively camouflage to look like their environment. The many species of decorator crabs attach seaweed, sponges, hydroids, and any other flappy materials to their shell to blend in with their surroundings.

Microscopic hooks cover the crab's shell to facilitate camouflage

Courtesy: Ruth Hartnup via Flickr, and

Monique Salazar and W. Randy Brooks via Journal of Marine Science

But sometimes blending into the background isn't enough. Sometimes, you've got to do more than look the part. Sometimes you have to live your role to complete the illusion. Enter the cephalopods.

Octopus, squid, cuttlefish, and nautilus are all cephalopods (pronounced: sef-a-lo-pod). Cephs are probably the most intelligent and adaptable invertebrates in the world. A closer look at their anatomy can help us understand why. Cephalopods don't have claws or spines; they're not very fast; they have a sharp beak, but they have to get close to use it; and except for nautiluses cephs don't have a hard shell to protect their squishy, protein-rich bodies. So what do you do when you lack anatomical defenses? You get smart.

The most famous of this class to have the smarts to watch another animal and copy its behavior is the appropriately named mimic octopus (Thaumoctopus mimicus).

<in a nasally mocking voice> "watch another animal and copy its

behavior is the appropriately named mimic octopus"

Courtesy: Rickard Zerpe via Flickr

Dude, don't copy me that's ridiculous.

"Don't copy me that's ridiculous."

Courtesy: Avi Alpert via Flickr

<The following was typed very fast so the mimic octopus couldn't possibly copy it quick enough, and we can all actually learn something>

Mimic octopuses are found on sandy bottoms in the waters around Indonesia, the Philippines, and Papua New Guinea. These sandy and silty bottom habitats have few rocks, little animal growth, and minimal algae to hide among. While mimic octos can change their colors to match the background just as well as their cousins; movement tends to break the illusion. Other octopus species take advantage of rocky reefs or coral crevasses to slink along unnoticed while in motion, but mimics don't have that luxury. They also typically have to swim farther and more often than octopuses in other habitats because their prey isn't concentrated in a small area. A swimming octopus is very distinct, so mimics exactly copy the swimming behavior of flounder to conceal their true nature. They bend all their arms around and cluster them together so their eyes are sticking up in front of a big flat disk. As their arms trail, the ends flap just like the fins of a flatfish. The octopuses even stop and start moving with the same frequency as flounders all while hugging the contours of the rippled bottom.

We don't know why, but sometimes the mimic octopus will keep its distinct pattern while moving like a flounder and sometimes it will change to the fish's usual coloration.

Courtesy: Klaus Stiefel and Bernard Dupont via Flickr

The internet is full of reputed stories of mimic octos copying other species as well. While reports of mimic octopuses mimicking lionfish, sea snakes, and stingrays are out there we should remember that octopuses evolved entirely without our perceptions in mind. This means that what may clearly look like a lionfish to us, may look nothing like it to a grouper hungry for a bite of octopus arm. However, it may be that the mimics' strategy is just to look like "not an octopus", and whatever other creatures they see, they try and copy.

Amazingly mimic octopuses aren't the only species of octopuses to mimic other creatures. Living in the same waters as mimics the excitingly named "blandopus", which has which hasn't been formally described yet, also copies flounder. And if you Atlantic Ocean folks have been feeling left out, don't worry. The Caribbean has a copy-cat octo as well. Atlantic longarm octopuses (Macrotritopus defilippi) live in a very similar habitat to mimics and blandopus, and also engage in flat fish plagiarism.

Some species just have no regard for copyright law.

Courtesy: Wayne via Flickr 

Clearly impersonating another animal is an effective way to avoid becoming someone's lunch. But can cephalopods use mimicry to catch their own prey?

Just off the coast of southern Brazil; in the southern summers of 1999, 2000, and 2001 a pair of scientists used lights shined from a boat to attract zooplankton. Light attractants like this are an important tool in many fisheries, particularly those for squid. Rodrigo Silvestre Martins and Jose Angel Alvarez Perez wanted to study how a community of predators and prey develop under these lights. Who's eating whom, how are they going about catching one another, and what could that mean for fisheries conservation? The researchers found that a column of animals, gradually increasing in size, formed under the lights. The smallest zooplankton were near the surface, and as you descended  progressively larger predators lurked, waiting for a chance to strike at the prey above them.

Lurking in the shadows is pretty typical behavior for any predator, but one squid species' actions caught Martins and Perez by surprise. Atlantic brief squid (Lolliguncula brevis) are an estuary specialized squid that eat small schooling fish like anchovy and sardines. During Perez and Martins' study they watched brief squid regularly mimic the shape, color patterns, and swimming behavior of anchovies in order to get inside their schools without being noticed before striking.

Brief squid isn't a cool enough name for these masters of infiltration.
I propose we call them "subterfuge squid" from now on.
Courtesy: NOAA Photo Library via Flickr 

Now, squid aren't the only cephalopods to pantomime another animal in order to get close to prey. We've found one species of cuttlefish engages in a similar behavior to creep up on reef fish.

Pharaoh cuttlefish (Sepia pharaonis) are a widespread, small cuttlefish found throughout the warm waters of the Indian and Western Pacific Oceans. In 2011 a team of Japanese researchers noticed their cuttles doing something weird when they were placed in a large open tank for an experiment. The cuttlefish pushed together their upper pair of arms and colored them like eyes on the end of stalks. Then they set their other arms at odd, jointed angles and started twitching them, seemingly at random. Lastly they colored their mantle a shade lighter than all of their arms. The whole illusion came together to look exactly like a hermit crab.

In case the video widget doesn't work, click here to watch the pharaoh cuttles in action; it's astonishing. The research team thought maybe the cuttlefish were mimicking to protect themselves from potential predators when exposed in a large barren tank; kind of like mimic octopuses pretending to be other animals when they're moving in the open. But the scientists were curious if faking crabbiness (definitely the scientific term) could also help the cuttles catch prey like brief squid pretending to be anchovies.

So in 2013 they collected more pharaoh cuttlefish and put them in a tank with small tropical damselfish. The cuttles that pretended to be crabs got closer to the schools and caught twice as many fish as those that hunted while acting like cuttlefish! So yeah, I'd say that's an effective hunting strategy.

As we begin to look closer at cephalopods we're starting to understand just how diverse and seemingly intelligent their behavior is. Mimicries like these are just a sample of the ways octopus and their cousins use their adaptable camouflage. So maybe pretending to be something you're not isn't always bad. Maybe we shouldn't deal in absolutes all the time and recognize that there's advantages and disadvantages to lots of behaviors and life styles. There's a lot to be learned still about cephalopods, but there's also a lot to be learned from them.

References:

Hanlon, Roger T., Watson, Anya C., & Barbosa, Alexander, "A 'Mimic Octopus' in the Atlantic: Flatfish Mimicry and Camouflage by Macrotritopus defilippi", Biological Bulletin, 218: 15-24, Feb. 2010.
Accessed via: http://www.journals.uchicago.edu/doi/10.1086/BBLv218n1p15

Hanlon, Roger T., Conroy, Lou-Anne, & Forsythe, John W., "Mimicry and Foraging Behaviour(sic) of Two Tropical Sand-flat Octopuses of North Sulawesi, Indonesia", Biological Journal of the Linnean Society, Jan. 2008.
Accessed via: https://academic.oup.com/biolinnean/article/93/1/23/2701347

Martins, Rodrigo Silvestre & Perez, Jose Angel Alvarez, "Cephalopods and Fish Attracted by Night Lights in Coastal Shallow-waters, off Southern Brazil, with the Description of Squid and Fish Behavior", Revista de Etologia, Vol. 8 No. 1 Pg. 27-34, 2006.

Accessed via http://pepsic.bvsalud.org/pdf/reto/v8n1/v8n1a03.pdf

Okamoto et Al., "Unique Arm-flapping Behavior of the Pharaoh Cuttlefish, Sepia pharaonis: putative Mimicry of a Hermit Crab", Japan Ethological Society and Springer Japan, May 2017.

Accessed via: https://link.springer.com/article/10.1007/s10164-017-0519-7

Naut Again

Oh wow, there's some wonderful news that's come out of the US East coast recently that hasn't gotten the coverage it deser....

"NAUT SO FAST PUNK!"

Courtesy: DarTar via Wikimedia Commmons

Oh, god no, not this again. How many weeks am I going to have to go without getting interrupted by a cephalopod? What do you want chambered nautilus (Nautilus pompilius), and did you seriously just use your own name as a pun?

"I'll use my name however I want after you and that wannabe 

Greek hero besmirched it. She should be proud to be 

associated with us nautiluses."

Courtesy: Michael Bentley via Flickr

Alright, alright, I didn't mean to offend anyone. I wrote about argonauts last week since they're a cool family in their own right. I guess I didn't think about how little people know about your family too. Tell you what, I'll make this post all about you, if you promise to tell the other cephs to stop interrupting me. I don't want a ram's horn squid butting in next week.

"Alright deal, but I'm gonna stand here and make sure you do us justice"
Courtesy: OCVA via Flickr

Okay well, if we're gonna give this family the credit it deserves we need to talk about world domination. Don't worry, you needn't imagine a future where shelled overlords subjugate earth's other species, because it already happened. Nautiluses are old, very old, in fact their family members are the OG cephalopods. The first nautiluses to appear had straight shells, but around 400 million years ago they developed the familiar spiral we see today. They were so successful that they, and their cousins the ammonites, would go on to dominate the seas for eons. Nautilus even survived the worst extinction of all time which killed 96% of all life in the sea. Not too shabby for an animal that's essentially a fancy snail.

Even though they ruled the oceans for so long, the nautiluses eventually gave up their family's dynasty to live a life of quiet retirement. Today only two genera of nautilus exist, down from the 75 or so at their peak. Modern nautiluses are found only in the Indian and Pacific oceans in the deep waters at the steep edges of coral reefs. Yet they are some of the most fascinating organisms to occupy those spaces.

Of course what stands out most about nautilus is their incredible shells. Nautilus are the only cephalopod left to still have an exterior shell, which means they don't need all the gaudy color and texture changing flashiness of their cousins. Instead of hiding, speeding away, or out-thinking their predators nautilus prefer the simple life scavenging food off the bottom; and cruising through deeper water at times when predators are at rest.

They're kind of like that friend from college who moves to
 Idaho and starts a goat farm because "It's just easier."
Courtesy: Hans Hillewaert via Wikimedia Commons



Now you might notice that the nautilus' shell is pretty burly. There are hardly any animals with shells that thick that even bother swimming. Other heavily shelled mollusks like clams and snails spend most of their time on or in the ground. So what does the nautilus do that makes it able to hover up in the water like that? Are they just incredibly strong? Not really. When you watch a nautilus puff along by forcing water through its siphon, it kind of makes you want to hand it an inhaler and tell it to go sit on the bleachers. So if it's not pure herculean strength that keeps the nautilus afloat what is it? Well my friends, the nautilus succeeds thanks to the magic of good engineering.

I think like a third of our readers just found their spirit animal
Courtesy: Jason Westley Upton via Flickr

Inside the shell are the structures that put the "chambered" in chambered nautilus. The largest chamber is where the nautilus' mantle is housed, but the others are empty of everything except air and a little bit of water. When a new chamber forms the nautilus walls its previous space off and amazingly, drains the water. See if the chambers stayed filled then the nautilus would get dragged to the bottom thanks to the weight of the water inside the shell. Emptying water from the chambers has the same effect as if the nautilus were to tie balloons to its shell. The air inside pushes up towards the surface while the weight of the shell pulls down, and the two forces balance one another out to make the nautilus neither sink nor float.

You might be wondering: If the nautilus seals the chambers how does it get the water out? Well running through the chambers is a really cool organ with a really cool name, a siphuncle (pronounced: sigh-fun-kull). The siphuncle is a tube that uses water's own physical properties to fill and empty the chambers. See water has a tendency to try and balance the concentrations of different minerals dissolved in itself. So if you put a screen that will only let water through between two solutions and you make one much saltier than the other; the water will cross the screen to the salty side until the two sides' ratios of salt to water are equal. This is exactly what the siphuncle does. When the nautilus wants to remove water from the chambers it adds salt ions to the outer layer of the siphuncle and the water just seeps on out of the chamber. When the nautilus wants to add water to the chambers it does the opposite. This system requires basically no energy on the animal's part, so it's a great strategy for staying properly buoyant.

Who says functional machines can't be pretty? Those little struts in the center 
of each chamber hold the siphuncle in place as it runs through the shell.
Courtesy: Jitze Couperus via Flickr

Of course everyone focuses on the shell of the nautilus, so much so that these animals are being impacted by fisher people catching them for their shells. Many scientists and citizens who care a lot about nautilus are doing everything they can to show the international community that nautilus, not only deserve, but need our protection. The easiest way to do your part is to never buy new nautilus shells. Instead look around antique stores, or purchase nautilus fossils, which have the benefit of being infused with beautiful minerals from fossilization.

Aside from their shells, nautilus are also impressive thanks to over 90 tentacles! These tentacles are much simpler than the complex arms of the nautilus' cousins. They have no suckers and instead use a series of grooves to grip surfaces. They're also incredibly sensitive to scent/taste. As a scavenger nautiluses need to be very aware of where food is sitting, and all of those tentacles act like an array of antennas picking up the fishy signal of food rotting on the bottom.

Okay nautilus, was that a satisfying amount of information for you? We can always come back another week and learn more.

"Well that was better than naut. It'll do for now, and naut to worry,
you've naut seen the last of me."
Courtesy: David Remsen via Flickr

Ugh, the puns man, the puns...

References:

Dunstan, A., Ward, P., & Marshall, N., "Vertical Distribution and Migration Patterns of Nautilus pompilius", PLoS ONE 6(2): 16311, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016311

Ward, Peter, "Cameral Liquid in Nautilus and Ammonites", Paleobiology, 5(1), 1979, pg. 40-49.
Accessed via: http://www.jstor.org.ezproxy.library.wwu.edu/stable/2400389?seq=1#page_scan_tab_contents

Crook, R., & Basil, J., "A Biphasic Memory Curve in the Chambered Nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea)", Journal of Experimental Biology, June 15th 2008.
Accessed via: http://jeb.biologists.org/content/211/12/1992.long

Dunstan et al., "Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia" PLoS ONE, 6(2): e16312, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016312

Precious Argo

How's the old saying go? "If it looks like a duck, swims like a duck, and quacks like a duck, then it's probably a duck."

"Quack?"

Courtesy: Derek Bruff via Flickr

By extension I can imagine this test applies to any animal. Let's pick a random one and try it, shall we? If it looks like a..... Nautilus, swims like a nautilus, and has a shell like a nautilus it must be a nautilus. 

"Oh my God! What did you just call me!?"

Courtesy: Michael Vecchione via TOLWeb.org

Oh yeah I'm sorry, paper nauti..... I mean greater argonaut (Argonauta argo). I totally forgot about you. How about I make the rest of this post about how awesome you, and the other three species in your family, are to make up for it?

"We can live with that. I'll just sit here and make sure you

 don't mess up again"

Courtesy: NOAA Photo Library via Flickr

Okay where to start? Well, how about at the very beginning like my nanny used to say. Disclaimer: My nanny may have just been Julie Andrews movies. Anyway, we've known about argonauts for an incredibly long time. Their delicate, paper-thin, shells have been found painted on artifacts from 4000 years ago! Of course, back then we barely knew anything about these animals because we were mostly finding their old shells washed up on the beach. 

However many of the ancient Greeks were talented naturalists, and they started looking closer at these coiled beauties. Aristotle noticed that the argonauts could climb out of their shells because they aren't attached to them like a true nautilus or any other shelled mollusk. So how did Aristotle think argonauts got their shell? Well he assumed they stole it. For the longest time scientists thought that argonauts couldn't be making their own shells, so they were taking them from an unknown animal and using them as boats. Now this seems a little crazy, but add in the fact that female argonauts have sail-like webs on two of their arms, and you have the perfect animal to send after the golden fleece. 

Hahaha...What is it even...? Hahaha...There's a boat to compare it to..Hahahaha!

Bless you for this: Gerard Van der Leun, via Flickr

Although the theory that argonauts combined Grand Theft Auto and that pirate Assassin's Creed (Hold on I have to go pitch an idea to Microsoft) persisted well into the 1800's, eventually science started to sober up. We later discovered that female argonauts make the shells using glands in their webs that secret calcite. They spread these webs out over the shell and lay down material bit-by-bit like nature's 3D printer. 

 On the left you can see the webs with chromatophores, extended over the shell.

On the right this female has pulled the webs back, exposing her construction.

Courtesy: Michael Vecchione via TOLWeb.org

 If you're an astute reader, you've probably noticed that I've only mentioned female argonauts so far. This follows the history of these animals because for the longest time we had no idea what the males looked like. Why? You might ask, well they're tiny, like really tiny, only 1% the size of a female, and the biggest species' female only gets to 30cm across. Plus the males don't build shells, oh and sometimes they only have seven arms.

See argonauts are octopuses, and they normally have eight arms like any of their relatives. However one of a male octopuses arms is very different from the others. The third arm on his right side is called a hectocotylus (pronounced: heck-toe-cot-oh-luss) and it's used for reproduction. The males of most bottom-dwelling octopuses insert their hectocotylus into the female's gill opening; and sit there for a bit while a packet of sperm passes from inside his body, down the arm, and into the female's oviduct. Argonauts don't have the luxury of that kind of time though. They differ from their cousins by living up in the water column, instead of down on the sand. Living in the open ocean is great way of avoiding competition with your cousins down below, but it also means you have to travel far and quick to find food, mates, and shelter. 

Because the ocean is so big, and argonauts so small, males may not have many chances to find a female. To make sure they mate effectively the male argonaut's hectocotylus actually breaks off inside the female's body cavity, and he swims away. By embedding his sperm delivery system in the female, the male has insured that it's his DNA that fertilizes the eggs. Plus it's a great way to screw with naturalists. This is not a joke, the scientist who first found a hectocotylus buried in a female argonaut thought it was a parasitic worm!

 Plus what the hell do we call this thing, a septopus?

The eighth arm is kept inside that pouch.

Courtesy: Edwald Rubsamen via Wikimedia Commons and Public Domain

Now here's where the functional beauty of the female's shell can accompany its aesthetic beauty. Since she lives up in the water there's very little to attach her eggs to, and good material could be floating hundreds of miles from the female argonaut, so she lays her eggs right inside the shell. Female argonauts handcraft baby strollers to push their kids around in until they hatch. Not only that, but the shape of the shell allows the female to trap air in its top which helps counter-act the weight of her body and the eggs; and keeps her from rising or sinking too fast. 

You can see the eggs hanging out of the lower part of this female's shell.

She's new to this whole arts and crafts thing.

Courtesy: Bernd Hoffman via Wikimedia Commons

So how'd I do argonaut? Did we cover everything that makes you so cool? Be fair, we don't know much about you since you're all so small and you live in oceans around the entire world.

Whoooo! Nice work! Go team Argo! High eights all around!

Courtesy A.E Verrill via Wikimedia Commons and Public Domain

References:

Finn, Julian K., "Taxonomy and Biology of the Argonauts (Cephalopoda: Argonautidae) with Particular Reference to Australian Material", Molluscan Research, 2013, Vol. 33, No. 3, 143-222.

Heeger, T., Piatowski U., & Moller, H., "Predation on Jellyfish by the Cephalopod Argonauta argo", Marine ecology Progress Series, Vol. 88, 293-296, 1992.

Orenstein, Marcie, "Marine Invertebrates of Bermuda: Paper Nautilus (Argonauta argo)", The Cephalopod Page, 

Accessed via: http://www.thecephalopodpage.org/MarineInvertebrateZoology/Argonautaargo.html 

Mangold, K., Vecchione, M., & Young, R., "Argonautidae", Tree of Life Project, 

Accessed via: http://tolweb.org/Argonauta

Maternal Instincts

Hi ho everyone! I know it's been forever since I last posted, and you're probably missing your weekly-ish fix of fascinating marine science and news. I've been enjoying an incredible field course through my university that has been eating up all my time. I might do a post about it at some point because we've spent some time doing ocean education. Anyway Depth and Taxa is back just in time for mother's day, so this week we'll be looking at some of the best moms the ocean has to offer.

All moms are willing to give up everything for their kids, but our first ocean mother takes this to a bit of a literal extreme. We've talked about how giant Pacific octopus (Enteroctopus dolfleini) are the largest in the world before, but there's a lot more to these incredible creatures than their size. After mating with one or more partners, female giant Pacific octopus lope off to find themselves a den. Sturdy shelters are an important part of octopuses' entire lives since they have no shell to protect them like other mollusks, but this will be a special space. The den the mother to be is looking for will be her nursery. Once she's found the perfect spot, she'll start braiding together 80-100 thousand eggs with her bare suckers. 

  "Oh you knitted those socks yourself? That's cute."

Couretsy: Ratha Grimes via Flickr

The mother octopus sticks these ropes of eggs to the ceiling where they'll spend the next five to seven months developing. In all that time mom never leaves the den. She sits in her nest, brushing her arms over the eggs to keep them clean, and pushing water from her siphon over them to keep them oxygenated. From the day she lays to the day the babies hatch she never eats a thing. All that devotion and starvation takes a severe toll on mother octopuses' and usually their last act is to push their adorable octolings out into the world with a blast water. 

It's certainly a beautiful story of motherly commitment, but why does it have to be so sad? Why can't mom stick around and raise her young. Well no one knows for sure, but it might have something to do with the fact that adult octopus compete to the point of occasionally eating one another.

 "One look at you and I can't disguise. I've got hungry eyes."

Courtesy: John Turnbull via Flickr

To find an ocean mom that keeps mothering long after her kids are capable of surviving on their own; we need to return to the more familiar world of mammals. 

Orcas, also called killer whales (Orcinus orca), are found across more of the world than most other mammals. In order to become so successful they've had to come up with some incredible strategies for survival. One of those strategies is recognizing that "mother knows best". Orca groups, called pods, are led by matriarchs who care for their children their entire lives. These mother-leaders remember where the best hunting grounds are, what areas to avoid, and where to go when food is scarce. Keep in mind that orcas can live as long as humans. A whale named Granny from the Salish Sea in the Northeast Pacific, is estimated to be 103 years old, far, far beyond reproductive age. A theory called the "grandmother hypothesis" suggests that the life experience of these mature females is so important that, evolutionarily, they contribute to the reproductive success of their pod even after they go stop reproducing. Of all the animals in the world only humans, pilot whales, and orcas are known to go through menopause, and their wonderful mothering may be why.

Courtesy: Mike Charest via Flickr

So who else is left? What other mother can compete with these two incredible species? Well the answer is simple, mine. My mom has been a big part of my life for as long as I've had it, and I want to dedicate this post to her this mother's day. Mom has always respected my goals and encouraged me to pursue the sea since I first responded "oceanographer!" when I was asked what I wanted to be when I grew up. 

The only thing that's changed in 21 years is that my brother 

doesn't fit in a dolphin anymore.

Mom and I always have wonderfully deep conversations about education and science, and she's been the number one supporter for the blog. I know that, like a giant Pacific octopus, my mom would give up everything to give her family a head start on life. But she'll also be around for years to come, to give me and my brother guidance, just like an orca matriarch. So since I know she's reading this, I just want to say thank you, thank you for everything, and Happy Mother's Day.

References:

No author, "Orcas of the Salish Sea, Part 1 & 2", The Orca Network. 

Accessed via: http://www.orcanetwork.org/Main/index.php categories_file=Natural%20History%20of%20Orcas%20-%20Part%201

Weiler, Nicholas, "Menopausal Killer Whales are Family Leaders", Science News, March 5th 2015. 

Accessed via: http://news.sciencemag.org/biology/2015/03/menopausal-killer-whales-are-family-leaders

Anderson, Roland C., Mather, Jennifer A., & Wood, James B., "Octopus: The Ocean's Intelligent Invertebrate",  Timber Press, May 21st 2010.

Stubby, Bobtail, Dumplings

Mollusks. Generally they're not a particularly cuddly bunch. For example, most people wouldn't call the inside of an oyster cute.

"D'aaaww who's a good boy?"

Courtesy: Larry Hoffman via Flickr

But there is one group among the mollusks that stands apart. The sepiolidae (pronounced seep-ee-oli-day) are an order of mollusks related to squid, octopus, and cuttlefish. More commonly these animals are called stubby, bobtail, or dumpling squid. None of the stubby squids get much bigger than around ten centimeters (about half the length of an unsharpened pencil), so they're round and small, which makes all of their common names very appropriate. The squid part of the name is a little misleading however because these animals show characteristics consistent with all of their cousins. They spend most of their lives on the bottom, like octopus; they have eight arms and two tentacles, like squid; and they have short rounded mantles, like cuttlefish. 

Who do you think you are? No, seriously I can't figure it out.

A Hummingbird bobtail (Euprymna berryi)

Courtesy: rtonyr via Flickr

Sepiolids are most closely related to cuttlefish which many people guess by the brilliant colors they can produce. Don't let the flashy get up fool you though; stubby squid are some of the best hiders out there. Not only can they change those colors to better match their surroundings, they're also master excavators.

Sepiolids are so cute that they even snuggle up in a blanket to sleep. They dig down by using their siphon (a tube coming from their body that they use to swim and breathe out.) to force water into the bottom and create a little depression. Then they settle down into it and use their arms to wrap themselves in a nice blanket of mud, leaving only their head sticking out.

Makes sense, you've got to wrap a dumpling 

to steam it properly

Courtesy: Nick Hobgood via Flikr

They spend most of the daylight hours tucked in deep water in their sandy beds and come out at night to hunt. Once they're on the prowl they'll often move to shallower water where they're sometimes encountered by lucky divers. 

So if they're this adorable as adults what do their babies look like? Well pretty much exactly like their parents. Dumpling squid have smaller egg clutches than many of their relatives. They lay up to about 50 eggs, which compared to a giant Pacific octopus' max of 100,000 is practically nothing. And unlike many of their relatives' babies, stubby squid don't spend time as a part of the plankton. The young sepiolids break out of their egg cases ready to roll, and walk away to find some food.

The eggs of the Pacific stubby squid (Rossia Pacifica) 

Courtesy: Chris Wilson via Flickr

You'd think that because these animals are so cute and charismatic that we'd know a lot about them. But because they live at the low end of recreational dive limits, are nocturnal, bury themselves, and tend to live on sandy bottoms which divers often ignore, we actually know very little about the lives of these cool little animals.

References:

Rodrigues et al., "Burying Behavior in the Bobtail Squid Sepiola atlantica (Cephalopda: Sepiolidae)", Italian Journal of Zoology, Apr 06, 2010

Anderson, Roland C.,  "Rossia Pacifica, Stubby Squid", The Cephalopod Page,

www.thecephalopodpage.org/Rpacifica.php