Curious Cuttles – Dwarf Cuttlefish (and friends)

    There appears to be some unspoken rule that tiny versions of things are exponentially more adorable. Take for instance hummingbirds, pygmy marmosets, dwarf elephants, pygmy hippos, or Brookesia micra (the chameleon that fits comfortably on the head of a match). The dwarf cuttlefish (Sepia bandensis), with a mantle length of under three inches, is no exception. Dwarf cuttlefish are at home in the warm waters of the Indo-Pacific including, but not limited to, the Philippines, New Guinea, and Sulawesi. Living mostly in shallow coastal waters, these tiny cephalopods are most active at night, feeding on small crustaceans or fish found over sand and reef. Like almost all members of their group, dwarf cuttlefish are exclusively shallow water inhabitants. This is because of the vestigial cuttlebone that’s contained within the mantle. The cuttlebone is a remnant from the ancient history of cephalopods. Like the ancestral shell, it still retains tiny chambers filled with gas that assist with buoyancy. As a consequence, the cuttlebone will implode if the poor creature swims too deep. Being relatively restricted to shallow water does have its perks, though. Since there is so much light, cuttlefish get to fully utilize their incredible skin to create a wide variety of colors, patterns, and textures to communicate with each other and other animals.

     One of the most spectacular displays used by these tiny cuttles is known as the “passing cloud”. It consists of dark bands of color moving down the animal’s mantle via the pulsing of chromatophores in the skin. While this occurs, the cuttlefish keeps the rest of its body’s color and pattern static (unchanging).

Here you can see the passing cloud display in action on this dwarf cuttlefish that I filmed at the Seattle Aquarium. It does it at the beginning and the end of the video.

S. bandensis is not the only cuttlefish species to display these strange, psychedelic waves. Many other cuttlefish do this as well, and also some octopuses. Not surprisingly, the display differs in each species and there are many variations of it. These bands can occur on almost any part of the body and go in different directions depending on the species. The delightfully named Wunderpus photogenicus, an octopus, pulses dark bands over its eyestalks. Perhaps the most interesting thing about pulsing displays like the passing cloud is that no one knows for sure what the purpose is.

Did you notice the pulses on Wunderpus’s eyestalks?

     There is a myriad of possibilities of what the displays could be used for. Some cephalopods, such as the broadclub cuttlefish (Sepia latimanus), almost certainly use these displays for hunting. These cuttlefish can sometimes be seen rapidly pulsing the chromatophores on their arms before pouncing on prey. It’s possible that the chromatic pulses mesmerize prey, holding them in place while the cuttlefish positions itself for a deadly strike. The Australian giant cuttlefish (Sepia apama) has been observed using pulse displays in spawning aggression and while drifting in and out of seaweed. These are both notable examples of how pulse displays can be used. Male cuttlefish are well known for displaying aggression to rivals with one half of the body, while showing receptivity to females with the other half. Communication is extremely important among cephalopods and pulse displays seem to serve this purpose well. Camouflage is also a famous attribute of cuttlefish and octopuses alike. Creating rhythmic waves that mimic the rippling light coming from the surface while drifting with the weeds is an excellent way to hide. It definitely puts those chromatophores to good use by helping protect the animal from predators.

This broadclub cuttlefish is using its chromatic pulses to hypnotize a crab. It has its two outer arms positioned in what is called a “branched coral” pose.

     The functions of chromatic pulse displays like the passing cloud are not as obvious in other contexts. The extraordinarily cute and adorably named flamboyant cuttlefish (Metasepia pfefferi) will pass waves over its body in as simple a situation as sauntering over an open mudflat. There is a possibility that, along with its bright colors, this could serve as a warning to potential predators. Cephalopod expert Mark Norman has found that the flesh of this little cuttlefish is incredibly toxic. However, this is only anecdotally recorded in the NOVA special Kings of Camouflage and there has been no scientific study published yet that analyzes the toxins. Toxic or not, the flamboyant cuttlefish uses it’s chromatophores to send a message, supporting the potential communication function of pulse displays.

This tiny flamboyant cuttlefish is too cute as it walks around strutting its stuff. Could it be saying “Don’t eat me, I’m toxic!”?

     It’s pretty clear that passing clouds and other pulses have specific uses depending upon the environmental or behavioral context of the animal creating them. That is, it’s pretty clear for most of the cuttlefish I’ve mentioned. Alas, the star of this article – the diminutive dwarf cuttlefish – still hides its secrets. Although I am privileged to have seen and video recorded the passing cloud behavior at the Seattle Aquarium many times, I still can’t figure out what these little cuttles are using it for. One minute, an individual may be hovering in place with wave after wave passing over its mantle and the next it will be almost completely black and fighting with a tank mate. From my pathetically inferior human perspective, it seems random. There is the possibility that these captive bred cuttlefish are behaving a little differently than they would in the wild, or that they are influenced by the presence of people. With so many variables, it’s difficult to tell what the dwarf cuttlefish are using it for without a full blown scientific study. Even with the most skilled researchers giving it their all, we will probably never know just what goes on in the minds of these tiny cuttlefish (or any of the other species).


This is a photo I took at the Seattle Aquarium. You can see the tiny suckers on this dwarf cuttlefish’s adorable little arms as it watches me through the glass.

     Cephalopod nervous systems are so different from our own that we can only make feeble guesses at how they think and feel about the world. Can you imagine having your brain directly connected to your skin so you could change color and texture in fractions of a second just by thinking? Me neither, but wouldn’t it be cool? That’s an everyday reality for almost all modern cephalopods and something we can’t even begin to relate to. As our understanding of these fascinating creatures improves and science gives us new ways of studying them, we may come closer to discovering what it all means. Until then, let’s just admire their beautiful and complex alien language for what it is – one of the many wonderful mysteries of the natural world.

1. Mustain, Andrea. “World’s Tiniest Chameleon Discovered.” LiveScience. Purch, 14 Feb. 2012. Web. 12 July 2017

2.“Stumpy-spined Cuttlefishes, Sepia bandensis.” MarineBio Conservation Society, n.d. Web. 2 March 2017.

3. How, Martin J., et al. “Dynamic Skin Patterns in Cephalopods.” Frontiers in Physiology, vol. 8, 2017, Accessed 31 July 2017.

4. Cuthill, Innes C. “Animal Behaviour: Strategic Signalling by Cephalopods.” Current Biology, vol. 17, no. 24, 2007, pp. 1059–1060. ScienceDirect, Accessed 31 July 2017.

5. Hanlon, Roger. “Cephalopod Dynamic Camouflage.” Current Biology, vol. 17, no. 11, 2007, pp. 400–404. ScienceDirect, Accessed 31 July 2017.

6. Osorio, Daniel. “Cephalopod Behavior: Skin Flicks.” Current Biology, vol. 24, no. 15, 2014, pp. 684–685. ScienceDirect, Accessed 31 July 2017.

7. Laan, Andres, et al. “Behavioral Analysis of Cuttlefish Traveling Waves and Its Implications for Neural Control.” Current Biology, vol. 24, no. 15, 2014, pp. 1737–1742. ScienceDirect, Accessed 31 July 2017.

8. Kaufmann, Gisela, director. Kings of Camouflage. NOVA, 2011.

9. Staaf, Danna. “Sheathing the Shell.” Squid Empire: the Rise and Fall of the Cephalopods, ForeEdge, an Imprint of University Press of New England, 2017, p. 112.

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Unfishy Fish

     What do you think of when someone says “fish”? The image of a salmon or goldfish probably pops into your mind. Or perhaps a colorful tropical reef fish. Odds are, you’re not thinking of a lipstick wearing, pancake shaped animal with frog feet and a long, pointy nose. You’re most likely not thinking of a Toblerone shaped shark with swirly nostrils either. The fact is, evolution doesn’t care what your idea of a fish is. It’s going to go with what’s successful and if it looks like a nightmare clown, so be it. Evolution doesn’t have a goal or a grand plan. What happens will happen and if something works, it persists.


A generalized fish body plan.

     So here we are with and ocean of oddities to explore. To start with, let me introduce you to something that looks more or less like a ‘proper’ fish, but didn’t get the memo about how to swim like one. Enter, the razorfish (Aeoliscus strigatus). This fish is elongated and laterally compressed, giving it a razor thin appearance, hence the name. It feeds on tiny zooplankton such as brine shrimp as it hides among corals and seagrasses. Razorfish swim vertically in small schools with their snouts pointed down at all times. It is not known exactly why they do this, but it’s certainly entertaining to watch. With razorfish, it’s always a synchronized swim show. For the razorfish, the warm waters of the western Indo-Pacific are the perfect place to engage in these underwater ballets.


A school of razorfish.

     Another weird, warm water inhabitant to be featured here is at home in the lower estuary of Derwent River in Tasmania and several other locations along the southeastern coast of Australia. Unfortunately, it is now critically endangered because of a multitude of factors including a low reproduction rate, habitat destruction, and suspected predation by an introduced sea star. The spotted handfish (Brachyonichthys hirsutus) has a sail like dorsal fin and large, webbed ‘hands’ which it uses to walk along the silty bottom. It belongs to of the order Lophiiformes, along with other strange members like deep sea anglerfishes and frogfish.


Spotted handfish.

Unlike many other fish, which hatch out as larvae that further develops outside the egg, spotted handfish emerge as tiny, fully formed versions of their parents. Rather than floating among the plankton of the open water, these babies stick to the sandy floor and live out the rest of their lives there. The peculiar reproduction habits of this fish are exactly what make it vulnerable to the northern Pacific sea star (Asterias amurensis). Before they become fish, the eggs are attached to stalked sea squirts and other vertical organisms that are extremely appetizing to the star. As a consequence, the eggs are devoured along with the sea star’s target prey. Conservation efforts have since been set in motion to save this unique Australian animal. Along with a captive breeding program and hope of reintroduction, there has been some success with providing manmade alternatives for the handfish to lay their eggs on. Handfish have been using these sticks and as a result fewer eggs are lost to the ravenous sea star. The spotted handfish is a protected species and one of the benefits that comes with that status is efforts to reduce silt and pollution within the Derwent River estuary and restore quality to the fish’s habitat. Even though the spotted handfish is still very much at risk, there is hope for it and therefore hope for other endangered animals.

     Our next fish is not nearly as well known as some of the others on this list. It doesn’t live in warm water either and instead spends its life thousands of feet down on continental slopes where the majority of the sun’s light fails to reach. Chaunax pictus, the pink frogmouth, is another member of the anglerfish order. It can only be glimpsed from the window of a submersible or through the eyes of an ROV sent to explore the depths of the ocean. There is virtually no data about its reproductive habits, life cycle, or population trend. One study of C. pictus in the Arabian Sea observed that it only eats small shrimps. With a dearth of information like this, the most interesting thing about this fish is its appearance. Imagine a squat, pink or orange potato with a scowl to rival that of Grumpy Cat and you’re pretty much there.


Pink frogmouth

The pink frogmouth uses its odd fins to crawl around over rocky slopes in search of prey when it’s not sitting motionless, camouflaged as a pissed off lump of cheese. The Chaunax in the video below starts walking at 1:55 if you’d like to see it in action.

     Slightly more attractive, though no more at home in shallow water, is the Caribbean roughshark (Oxynotus caribbaeus). One of the few fish on here that isn’t part of the anglerfish order, it is closely related to the more commonly seen prickly dogfish (Oxynotus bruniensis). Almost nothing is known about the natural history of the Caribbean roughshark other than that it inhabits the upper continental slope from the Gulf of Mexico to Venezuela. This shark has sloping sides and a concave belly that give it the appearance of an animal that was forced through a triangular Play-Doh mold. Its sandpapery skin is pale gray to white with dark brown patches, which actually make it quite striking.


Caribbean roughshark.


Swimming Toblerone

The prickly dogfish is less showy, but just as oddly shaped. The scales are raised and conical like studs making it truly deserving of its name. Like the Caribbean roughshark, it is small, only reaching a little over two feet from snout to tail. It has a mouth reminiscent of the cookie cutter shark and feeds on the eggs of other Chondrichthyans (cartilaginous fish). Prickly dogfish can be found in shallower water than roughsharks, but are also seen at great depths.


Prickly dogfish.

Sharks are generally thought of as sleek and streamlined predators designed to kill, but these two species just reinforce the fact that every family has some real weirdos.

     Now we get to my personal favorite, and arguably weirdest of this group, the batfish. Despite their name, the batfishes, or Ogcocephalidae, don’t resemble bats in the least. In fact, they might be more suited to the name clownfish if that weren’t already claimed by the well known anemonefish everyone knows and loves from “Finding Nemo”. All batfishes are strange looking, but the red lipped batfish (Ogcocephalus darwini) takes the cake. With flattened body, nose-like face protrusion, and bright red lipstick looking like it was put on while drunk, this fish could be mistaken for a clown at a sorority party gone a little too far.

NGS Picture ID:1231868

Hey there, beautiful!

Also called the Galapagos batfish, it does indeed inhabit the warm, shallow waters of the Galapagos islands and nowhere else. It can be found swimming very awkwardly along reef edges over sandy substrate where its prey resides. Much of the time, it doesn’t even bother to swim. Instead, it crawls along the sand like a squashed frog and pauses frequently to lure prey.

Whereas many of its angler relatives use a nifty lure that comes out near the head region, the red-lipped batfish has one just above its lips under that pointy nose, which makes it look exactly like it has a perpetual booger hanging out of its nostril. The lure is bobbed up and down, acting as both a visual and chemical attractant for small invertebrates and a turn off for anyone else.

     Of course, it’s not this poor batfish’s fault that it looks so ridiculous. It has evolution to thank for that. For some reason, this strange body plan worked and stuck around as a result. The same goes for the rest of the fish featured in this article and so many more that it would be impossible to cover them all here. This was just a taste of the numerous odd ducks of the fish world and hopefully another motivation to keep exploring the stranger things out there. You never know what we might find next.


1. Clemens, Danny. “The Red-Lipped Batfish Is Always Ready for a Night on the Town.” DSCOVRD. Discovery Channel, 07 July 2015. Web. 21 July 2016.

2. Montoya, P. Zelda, et al. “The Natural History and Husbandry of the Walking Batfishes (Lophiiformes: Ogcocephalidae).”DRUM and CROAKER: 6.

3. Schulz, Katja. “Galápagos Batfish – Ogcocephalus darwini.” Encyclopedia of Life. EOL, 2014. Web. 21 July 2016.

4. Rijnsdorp, A. D., M. Costa, and T. Munroe. “Chaunax pictus (Pink Frogmouth, Redeye).” IUCN. IUCN Red List of Threatened Species, 2015. Web. 21 July 2016.

5. Leandro, L. “Oxynotus caribbaeus (Caribbean Roughshark).” IUCN. IUCN Red List of Threatened Species, 2004. Web. 21 July 2016.

6. McGrouther, Mark. “Prickly Dogfish, Oxynotus bruniensis.” Australian Museum. Australian Museum, 2 Dec. 2013. Web. 21 July 2016.

7. McGrouther, Mark. “Spotted Handfish, Brachyonichthys Hirsutus.” Australian Museum. Australian Museum, 3 Sept. 2015. Web. 21 July 2016.

8. “Spotted Handfish (Brachyonichthys hirsutus).” Wildscreen, n.d. Web. 21 July 2016.

9. Capuli, Emily Estelita. “Aeoliscus Strigatus.” FishBase. Ed. Roxanne Rei Valdestamon. Sea Around Us, n.d. Web. 21 July 2016.

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Are Pokémon Animals?

I have mentioned Pokémon before in my articles, but have only in passing. I now think it is time to take a scientific approach and look at these interesting, fictional organisms through the lens of science. Before we explore the title question, we first need to define what constitutes an animal. Animalia is one of the seven (as per the most recent revision of biological classification) kingdoms of life. The others are Plantae, Fungi, Protozoa, Chromista (diatoms, brown algae, etc.), Archaea, and Bacteria. Animals are multicellular, eukaryotic, heterotrophic organisms that lack cell walls. The cells are grouped into tissues, with each tissue having a specific purpose. Sponges, which are essentially just a clump of cells without any body symmetry, are the exception. As there are no sponge Pokémon to date, we do not have to worry about this. Animals must be able to move voluntarily and independently at some stage in their lives and develop until they reach a fixed body plan.


Protista is used here rather than Protozoa, but they both constitute the same types of organisms.

So, are Pokémon animals? The answer is, it’s hard to tell, but they probably are. There isn’t a way to know whether or not a Pokémon’s cells have cell walls because there is no data about their cellular structure, so we don’t have this to go on. All Pokémon appear to have body symmetry, one exception being Ditto. Ditto throws a wrench into the equation because it has an amorphous form, but can reorganize its body structure to take on the appearance and abilities of any other Pokémon. However, Ditto may be the result of a failed human experiment to clone Mew, the ancestor of all Pokémon. For this reason, we will exclude Ditto from our discussion because it was created through human intervention and did not evolve naturally. We’ll come back to Pokémon “evolution” later.


This Ditto is sad because it doesn’t fit in.

Another stumper is when we start to consider Pokémon diets. Most seem to be heterotrophs, like animals, but some are described feeding exclusively on rock or metal (lithotrophs), while some can photosynthesize (autotrophs). Heterotrophs are organisms that must use organic carbon sources for energy because they cannot fix it themselves like other organisms. Plants can. They convert light energy into more complex organic compounds through photosynthesis. A handful of Pokémon actually are able to sustain themselves on nothing more than electricity. Does this mean that these rock, metal, and electron eating Pokémon species are not animals? Not necessarily. We haven’t learned all there is to know about Animalia yet and it is possible that there are animals yet to be discovered with highly diverse diets that deviate from the standard heterotroph. Many of Pokémon are also capable of enjoying Pokémon food that is made from berries and other organic material, as well as treats such as Pokéblocks (candy for Pokémon) or Poffins (a pastry-like Pokémon treat). Even Pokémon of the Ghost Type, the majority of which appear to be non-corporeal beings, will take Pokémon food if it is offered.
Many real life animals will often consume non-organic substances such as clay to supplement their diets or neutralize toxins in their food. However, this alone is not enough to sustain them. Animals MUST ingest other living things or their products to survive. There is nothing that says that the stranger Pokémon species need to eat something other than iron ore or enough dirt to make an entire mountain.


Aron, the iron eater.


Larvitar, the mountain eater.

Some Pokémon are very plant-like. These are the Grass Type Pokémon. Many of them have abilities like Chlorophyll or Solar Power. Some of these Pokémon species look more like animals that others, though, so how can they be plants? The answer is: they don’t have to be if they participate in mutualism. Mutualism is a form of symbiosis in which both parties benefit from an interaction. It could be that all of the photosynthesizing Pokémon are hosts for special algae or other organisms that can fix carbon so that it is usable. In return, these Pokémon provide their little sun factories with precious nutrients. A few existing animals do this too, so it’s not really that out there to consider it in Pokémon.
Pokémon fill all the requirements of being animals except for their diets. We are still learning much about many strange metabolisms and food preferences in the animal kingdom, so I don’t think we can exclude Pokémon from Animalia just for this, as I mentioned above. We’ll keep exploring their biology.
Getting back to that “evolution” thing. Most, but not all Pokémon, go through “evolution”. Pokémon “evolution” is different from the Darwinian evolution that we know and love. It is predictable and occurs within the same individual. Pokémon evolution is analogous to metamorphosis in the real world. In fact, there are some Pokémon species that perfectly follow metamorphosis in real animals like butterflies, moths, and frogs. Pokémon can also be confirmed to have a Darwinian evolutionary history simply because of the fact that there are “ancestor Pokémon” like Mew that contain the basic genetic blueprints of all future Pokémon, and “fossil Pokémon” such as Omanyte and Anorith. Natural Selection seen in the Pokémon world emphasizes the presence of Darwinian evolution as well. Different regions provide a wide variety of habitats and the Pokémon found in these areas are well adapted to the conditions. This suggests that there is a process of adaptation over generations of Pokémon that resulted in the ones we see today that thrive in their respective environments.


Mew, the ridiculously cute ancestor of all Pokémon.

At this point, I feel that is safe to place Pokémon within Animalia. If they existed, they would make up their own separate phylum. Pokémon are incredibly diverse, and many don’t even look like they are related at all. But, just take a look at our own phylum, Chordata. There is a ridiculous amount of variation within it. Chordata contains animals ranging from simple, filter feeding tunicates, all the way to elephants, whales, birds, snakes, and of course, humans. Pokémon can take the form of gargantuan, dragon like creatures, or something as out there as a living pile of garbage. As briefly mentioned, there are different Types (18 in all) of Pokémon. Pokémon of the same type share similar abilities, weaknesses, and strengths. There is a Primary Type, and a Secondary Type. These Types could be thought of as analogous to classes within biology. Secondary Types would comprise the subclasses. For example, a Pokémon could be of the Fire Type class, but also belong to the Ground Type as its subclass.


The 18 Types of Pokémon.

But why did I choose class rather than some other higher or lower taxonomic ranking? It is because class seems to fit the variation observed within Pokémon types quite nicely and is a good reflection of a class such as Mammalia (our class). Every member of Mammalia is, by definition, a mammal. The blue whale is the most massive animal to have ever lived on this planet, yet falls into the same biological class as the tiny, extinct Batodonoides vanhouteni (a shrew-like mammal) and egg-laying mammals like platypuses and echidnas. Though they differ greatly, all these animals have a handful of defining features that set them apart from any other class. As is their namesake, all mammal species are capable of producing milk through mammary glands. Likewise, a Pokémon belonging to a specific Type will also share similar traits with fellow members of that Type that others don’t possess (unless those others have it as their Secondary Type/subclass). Water Types, for example, all appear to have increased fitness in rain and become weakened and dehydrated by hot, dry weather.


Swampert is a Water/Ground Pokémon. This means that its Primary Type is Water and its Secondary Type is Ground. Because of this, it has the unique traits of both Types. It is also one of my favorite Pokémon!

As with animals, there are many other ways to rank Pokémon taxonomically. We could break them into phyla, orders, families, genera, and individual species. Analysis of all taxonomic rankings like this would probably go on for pages and pages, so we will cut it off at classification by Type and the educated assumption that Pokémon are in fact part of Animalia. Even though these creatures are not real, it is always fun to speculate and dig into the “what ifs”. This curiosity and exploration is the whole basis for science fiction, one of the most popular genres of all time, and it enriches our imaginations and our lives.

1. Myers, Phil. “Animalia (animals).” Animal Diversity Web. Univerisity of Michigan Museum of Zoology, 2001. Web. 04 Dec. 2015.

2. Ruggiero, Michael A., et al. “A higher level classification of all living organisms.” PloS one 10.4 (2015): e0119248.

3. Venn, A. A., J. E. Loram, and A. E. Douglas. “Photosynthetic symbioses in animals.” Journal of Experimental Botany 59.5 (2008): 1069-1080.

4. Trench, R. K. “The cell biology of plant-animal symbiosis.” Annual Review of Plant Physiology 30.1 (1979): 485-531.

5. Barbo, Maria S. The Official Pokémon Handbook. New York: Scholastic, 1999. Print.

6. “Type.” Bulbapedia. Web. 23 Dec. 2015.

7. Bloch, Jonathan I., Kenneth D. Rose, and Philip D. Gingerich. “New Species of Batodonoides (lipotyphla, Geolabididae) from the Early Eocene of Wyoming: Smallest Known Mammal?”. Journal of Mammalogy 79.3 (1998): 804–827.

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Ancient Treasures of Puget Sound – Bluntnose Sixgill Shark

Love them or hate them, sharks are critically important to the health of our oceans. That’s just an undeniable fact. As apex predators, they have far reaching effects that help regulate the ecosystem down to the level of organisms on which they do not even directly prey. These incredible, ancient fish have been around for many millions of years longer than any dinosaur and have remained relatively unchanged since. Currently, however, more than 60 percent of all shark species on the planet are somewhere on the spectrum of threatened to critically endangered. This is extremely wrong. Animals that have survived for so long and through so much should not be pushed to the edge of extinction by the ridiculous blunders of such a self-absorbed species. Thankfully, there has recently been a worldwide effort to protect sharks and a decline of practices like the slaughtering of sharks for their fins or livers and recreational shark fishing.


Pictured: A cruel, wasteful, and shameful practice.

Here in Puget Sound we are very fortunate to have bluntnose sixgill sharks (Hexanchus griseus). These Sound sharks are now protected after a closure on recreational sixgill fishing was put into action by the Washington State Department of Fish and Wildlife (WDFW). This ban was in response to public outrage over the capture of several local sixgills from Elliot Bay fishing piers. The WDFW also initiated a research program with the Seattle Aquarium, the National Oceanographic and Atmospheric Association (NOAA) Fisheries Service, and other scientific partners such as the University of Washington, Point Defiance Zoo and Aquarium, and Vancouver Aquarium in an effort find more about these little known, deep water sharks.


Thanks to efforts like these, we now have more information about sixgills, especially in Puget Sound. Sixgills, as with other deep water animals, have consistent daily patterns. They migrate down to great depths during the day and rise to shallower water at night. This is called diel vertical migration and is largest mass movement of organisms on the planet at one time. However, Puget Sound sixgills are often found in much shallower water than is typical elsewhere – sometimes as shallow as about ten feet during the day. Fortunately, this makes them easier to research. Through capture and tagging studies, it has been determined that most of the sharks in Puget Sound are sub-adults. It is suggested that Puget Sound may serve as a nursery for these animals until they have reached sexual maturity and leave to lead a more pelagic lifestyle. Not only are these sixgills young, but there is a high level of relatedness among juveniles that inhabit the same area. DNA studies found that sharks that were punch biopsied within the same set were significantly more likely to be related to each other than not. These sets consisted mostly of siblings and half siblings. From all the sharks sampled in Puget Sound during this study, analysis resulted in the identification of 33 cohorts. The stranding of a large adult female carrying 71 full-term pups in southern Puget Sound gave researchers an opportunity to look at relatedness within a litter, and confirmed the suspicion that females are polyandrous, that is, mating with more than one male during a breeding season. Six male sharks contributed to the genetics of this litter, but the contribution was unequal because only a few of them contributed the majority of the genotypes found.


This neo-natal pup shows the green eyes and long upper portion of the caudal fin that are characteristic features of sixgill sharks.

Litters can range from 22 to 108 pups and gestation is hypothesized to be no less than 12 months and quite likely closer to 24 months or more. During breeding, male sharks appear to nip at the female’s gill area to get her attention and to entice her to mate as evidenced by white marks observed by biologist divers only during this time of the year. Similar behavior is seen in other shark species. Female sixgills mature at around 14 feet and males at closer to 10. As with many sharks, sixgills seem to grow slowly, but not a lot is known about age at maturity or rate of growth. One shark was found to double in size over its first year of life and then was recaptured later appearing to have grown around a third of an inch per month since. This is just one individual, however, and a much larger sample across different populations would be needed to fully understand sixgill growth rate.


At full size, the biggest sixgills can grow to a little over 15 feet, making this shark the largest fish in Puget Sound and one of the largest living sharks in the world. As their name suggests, they have six gill slits behind the head rather than the usual five found in most sharks. Their snouts are large and rounded, hence bluntnose, and protrude in front of jaws containing very unique teeth. The upper jaw has rows of thin, hook-like teeth that are common in many shark species. However, the lower jaw contains teeth that differ highly from those of other sharks. These teeth from rows of six on either side of the jaw and are deeply serrated like saw blades. Teeth like this are very similar to those seen in Jurassic sharks, suggesting that this species is quite ancient and primitive. Since these animals normally spend their time in very deep water (up to over 8,000 feet down – to put this in perspective, a mile is 5,280 feet) where food is scarce, they take every opportunity to scavenge when they can. Having saw like teeth on the lower jaw and puncturing teeth on the top jaw help them hold and saw through large chunks of flesh such as whale blubber. This allows them to remove more manageable pieces from huge carcasses, which they then swallow whole.


Illustration of upper and lower teeth

Not only are sixgills adaptable, deep sea scavengers, they are also skilled predators. These fish are capable of surprisingly great bursts of speed that contrasts with their sluggish appearance and behavior. Prey can include anything from crabs, mollusks, and teleosts (bony fish) to other cartilaginous fish or even marine mammals. Despite this, there has never been a serious injury or fatality recorded as a result of interaction with a sixgill shark. On the contrary, people often go on dives in Puget Sound specifically to see them. Sixgills do not appear to fear humans and show inquisitive behavior when they encounter one. If a person gets too close for the animal’s comfort, it will calmly swim away. Touching a sixgill may cause it to whip around and nip at the diver in warning, but no injuries usually occur and those that do are minor. Still, sixgill sharks are very big and powerful animals that should always be treated with caution. Even biologists who study sixgill behavior and are very knowledgeable will conduct their research from the safety of a shark cage or a boat and give the sharks their space when diving with them.


For the research that has been done on bluntnose sixgill sharks, we have barely touched the surface when it comes to understanding their lives and the ecological roles they play. What we do know gives us even more incentive to protect and study these amazing creatures. If Puget Sound is in fact a nursery for pups and young adult sharks, then it is a valuable resource for maintaining the genetic diversity of this species. Many shark species suffer from low genetic diversity caused by human actions and the fact that they reproduce slowly. Puget Sound sixgills, even with the relatively high number of related individuals, still shows moderate genetic diversity. Preserving safe and productive areas like Puget Sound is crucial to the survival of shark species worldwide. Sharks are excellent indicators of environmental health and where they do well, other species will undoubtedly thrive as well. Helping sharks like Puget Sound sixgills helps improve our planet’s oceans little by little, and in turn, our lives.

1. Martin, R. Aidan.  “Swimming with Jurassic Sharks.” ReefQuest Centre for Shark Research (2003).

2. Larson, Shawn, et al. “Relatedness and polyandry of sixgill sharks, Hexanchus griseus, in an urban estuary.” Conservation Genetics 12.3 (2011): 679-690.

3. Ebert, David A. “Biological aspects of the sixgill shark, Hexanchus griseus.” Copeia (1986): 131-135.

4. Andrews, Kelly S., et al. “Diel activity patterns of sixgill sharks, Hexanchus griseus: the ups and downs of an apex predator.” Animal Behaviour 78.2 (2009): 525-536.

5. Andrews, K. S., et al. “Acoustic monitoring of sixgill shark movements in Puget Sound: evidence for localized movement.” Canadian Journal of Zoology 85.11 (2007): 1136-1143.

6. Rupp, J. “A natural history of the sixgill shark, Hexanchus griseus.” Proc Puget Sound Res (2001).

7. Bauml, J. “Hexanchus griseus.” Animal Diversity Web (2004). Web. 11 Feb. 2016

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What You Didn’t Want to Know About Part III: Sexy Legs – Ricinuleids

The arachnids belonging to the order Ricinulei, or hooded tick spiders, are neither spiders nor ticks. At first glance, these primitive arachnids look a lot like your typical spider. However, if you look closely you will notice that they have segmented abdomens unlike spiders and a complete lack of eyes. It’s like they were trying really hard to cosplay as a spider but missed most of the critical details on their costume. Even so, you’ll probably never have to worry about making this distinction because ricinuleids are rare in comparison to other arthropods. Though locally abundant, only 55 species worldwide have been identified since the order’s discovery in 1838 and specimens are few and far between. A fossil of an extinct Carboniferous species was found in 1837, but the guy who found it thought it kind of looked like a beetle, so it wasn’t identified as a ricinuleid until later. Extant species are found in tropical regions of Central America and western and central Africa where they live in soil and litter.


I can’t decide what I want to be, so I’ll be everything!

Very little is known about this animal group even today, but scientists do know that males use their modified third pair of legs for sex. That’s important. Not just because it’s funny, but because looking at ricinuleid junk can be critical to species identification. These legs are used to hold and then transfer seminal fluid into a mounted female’s genital opening. Females store the sperm for later when they are ready to fertilize their eggs. The eggs are laid singly and sometimes carried around by the mother that laid them. Interestingly, baby ricinuleids hatch with only six legs instead of the usual eight that is the signature of arachnids. This and other morphological features is shared with Acari, or mites and ticks, and is believed to be indicative of a close relationship with that order. As the young develop, they grow their final pair of legs and start to look more like proper arachnids.


This is what the female gets stuck up her lady parts…

If you are so inclined, this paper has an even better picture of the male pedipalp:

Why are they called “hooded” tick spiders? The spider and tick parts of the common name are understandable, as they look a bit like spiders and are related to mites and ticks, but what about them is hooded? As it happens, ricinuleids have a cute little hood on their heads called the cucullus that can be raised or lowered at will. When the hood is down, it covers their mouthparts completely. How polite! The purpose and function of this structure is not yet understood, but it is one of their most defining features.


I’m not going to show you my mouth because that would be rude.

Ricinuleids may not be as fierce looking as amblypygids or as cool as vinegaroons, but they’ve been around the block and certainly have their own special quirks. So give them a round of applause for just sticking with it and existing all these years. If any order goes unappreciated, it’s the hooded tick spiders.

1. Harvey, Mark S. Catalogue of the smaller arachnid orders of the World: Amblypygi, Uropygi, Schizomida, Palpigradi, Ricinulei and Solifugae. CSIRO publishing, 2003.

2. Harvey, Mark S. “The neglected cousins: what do we know about the smaller arachnid orders?.” Journal of Arachnology 30.2 (2002): 357-372.

3. Adis, Joachim U., et al. “On the abundance and ecology of Ricinulei (Arachnida) from Central Amazonia, Brazil.” Journal of the New York Entomological Society (1989): 133-140.

4. Ewing, H. E. “A synopsis of the American arachnids of the primitive order Ricinulei.” Annals of the Entomological Society of America 22.4 (1929): 583-600.

5. Platnick, Norman I. “A new Cryptocellus (Arachnida: Ricinulei) from Brazil.” Journal of the New York Entomological Society (1988): 363-366.

6. Talarico, G., J. G. Palacios-Vargas, and G. Alberti. “The pedipalp of Pseudocellus pearsei (Ricinulei, Arachnida)–ultrastructure of a multifunctional organ.” Arthropod structure & development 37.6 (2008): 511-521.

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What You Didn’t Want to Know About Part II: Smells Like Vinegar – Uropygids

The order Uropygi (Thelyphonida) contains animals that are essentially really buff scorpions with whips on their butts instead of stinger tipped tails. They are often called whip scorpions for this reason. Another popular name for uropygids is vinegaroon because they use this whip to spray a mixture of acetic acid (vinegar) and other compounds when threatened or harmed. Their bodies are bulky and well armored, with powerful crushing structures on their pedipalps. These spine-like protrusions are used to capture and hold prey before tearing it apart. Similar to amblypygids, their elongated first pair of walking legs are held out in front to help with navigation. All of these features can make vinegaroons appear larger and scarier than they actually are, at least to us. The largest species in the world, Mastigoproctus giganteus, only reaches a maximum length of 3.3 inches, which is not huge compared to other arachnids.


Do you think you’re tough enough to take me on?

Fearsome as they may look, vinegaroons fit with our running theme of tender arachnid sex. When it’s time to make babies, the male gently grasps the female’s antenniform legs and then turns around so that they are both facing the same direction. He deposits a spermatophore on the ground and then grabs it, turns around again, and places it into the female during an abdominal embrace. She can then fertilize her eggs and will lay them within a few months. To do this, she digs a burrow and seals herself inside. Eggs are laid into a sac on the underside of her abdomen, which she holds aloft so as not to drag the eggs on the ground when moving. She does not eat during this time, which is impressive because it can take several months for the eggs to develop and hatch. Newly hatched vinegaroons ride on their mother’s back until their first molt.


Arachnid sex in action!

Most species from this order inhabit tropical regions, but a few, like M. giganteus, live in arid desert environments like many of their true scorpion cousins. M giganteus can be found in the American Southwest and Mexico where it serves an important role as a predator of pests such as cockroaches and crickets. This vinegaroon was the subject in a study by Schmidt et al. (2000) to better understand the composition of the spray. It was often believed that vinegaroon secretions contain formic acid in addition to acetic acid, but this is false. The study analyzed the fluid within the pygidial glands of vinegaroons of different ages and sexes and found that none contained formic acid. The major components of vinegaroon spray are acetic acid, which gives it the strong vinegar smell, octanoic acid, and water. The purpose of this fluid cocktail was also reevaluated in the study. It was only ever used in self-defense, and even then only if that vinegaroon was directly attacked. It appears as though predators are not deterred by being sprayed inside the mouth. However, any contact with sensory tissue such as the eyes, skin, or an arthropod’s feelers can be irritating enough to put off the attacker. In one particular trial, the researchers placed a sulfugid (camel spider) in with a first instar (between first and second molt) vinegaroon and it got a face full of spray. After that, it ran around the cage frantically trying to clean its face with sand and refused to touch another vinegaroon after that. Adult vinegaroons have little to fear, for they are powerful predators themselves and have tough armor to protect them. In the event that they are attacked, though, the spray is an effective way of letting the predator know to back off.

These animals demonstrate that you don’t have to be big, aggressive, or venomous to make it in this world. When faced with danger, you don’t have to fight. Just be really irritating and maybe you’ll be left alone!

1. Schmidt, Justin O., et al. “Chemistry, ontogeny, and role of pygidial gland secretions of the vinegaroon Mastigoproctus giganteus (Arachnida: Uropygi).” Journal of insect physiology 46.4 (2000): 443-450.

2. Rowland, J. Mark, and John AL Cooke. “Systematics of the arachnid order Uropygida (= Thelyphonida).” Journal of Arachnology (1973): 55-71.

3. Harvey, Mark S. Catalogue of the smaller arachnid orders of the World: Amblypygi, Uropygi, Schizomida, Palpigradi, Ricinulei and Solifugae. CSIRO publishing, 2003.

4. Harvey, Mark S. “The neglected cousins: what do we know about the smaller arachnid orders?.” Journal of Arachnology 30.2 (2002): 357-372.

5. Pocock, R. I. “Arachnida.” The Fauna of British India, including Ceylon and Burma. London: Taylor and Francis, 1900. 100-131.

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What You Didn’t Want to Know About Part I: What the HELL are These Things?! – Amblypygids

We all know (or hopefully we do) that spiders and scorpions are arachnids – arthropods with eight legs belonging to the class Arachnida – but let’s talk about some of the stranger members of this taxonomic group you’ve probably never heard of. Amblypygi, Thelyphonida (the Uropigids), and Ricinulei. What are those?! To be perfectly frank and scientific here, all of these orders are hella weird. Let’s start with Amblypygi.
What happens when you combine a scorpion, a spider, a mantis, and your worst nightmares?

Heterophrynus sp.

You get this gorgeous fellow! Amblypygid means “blunt butt” because these arachnids have no tails, unlike the one we’ll get to in the next part. They are commonly called whip spiders, tailless whip scorpions, or “that thing that Mad-Eye Moody (actually Barty Crouch Junior disguised with Polyjuice Potion – spoilers!) demonstrated the unforgivable curses on in Harry Potter and the Goblet of Fire”, all of which are much easier to pronounce than amblypygid. With leg spans easily reaching over a foot in some species, Amblypygi are the world’s largest living arachnids. Despite their fearsome appearance and movie monster like habits of hanging out in dark places and mainly emerging at night, they are completely harmless to humans. The worst you can get from one of these guys is a minor rose thorn prick from their pedipalp spines and a good scare (and this is if you really push their buttons). Personally, I don’t find them scary at all, but I’m sure a lot of people do. You can actually get them as pets if you’re that weird. Thankfully for my family, I’m not that weird (maybe).
Whip spiders inhabit tropical and sub-tropical regions where their flattened bodies make it easy to sit under bark, under rocks, and in all other stereotypical creepy crawly hiding places. Some are even found in caves and like to hang from the walls or ceiling with their footpads, or pulvilli. At night, they will come out to hunt and get it on with other whip spiders. When this happens, some form of courtship ritual occurs which differs across genera. The male whip spider then backs up toward the female and places a spermatophore (a capsule of sperm) on the ground in front of her before turning to face her again. He entices her to step forward over the spermatophore and take the sperm into her genital opening. After this process the sexes separate and the female later lays eggs into an egg sac under her abdomen. The babies that hatch will ride on her back until after the first molt when they are ready to move around on their own. Tough luck if they accidentally fall off before this, though, because they get no help whatsoever to climb back on and will surely die.


Whip spider babies, like most other arachnids, are miniature versions of the adults. These animals have an unusual first pair of legs. They are so ridiculously elongated and multisegmented that they have taken on the role of antennae and are no longer used for walking. The antenniform legs are held out in front of the animal to help it with navigation and prey location. These “whips” are what give this arachnid its common names. Cave dwelling species often possess even longer legs and some lose their pigmentation and have a reduction or loss of eyes. Amblypygids weren’t even described until the first one was found by Linnaeus in 1758. Up until the mid-1800s, very few more species were named and the number of species fluctuated greatly in the 1890s. Today, there are 136 separate species described with the prediction that this number will climb as the different genera are examined further.

Perhaps the most interesting thing about amblypygids is that some species are social and regularly aggregate in small to large groups. Occasionally this will occur in an outhouse, much to the dismay of anyone needing to use it. In 2006, a study was conducted at Cornell University’s Department of Entomology by Linda Raynor and Lisa Anne Taylor on social interactions in two species of amblypygid, Phrynus marginemaculatus and Damon diadema. What they found was actually pretty sweet… for an arachnid. For the first four months of their lives, both species in the study stayed close to their mother and oriented toward her. She would actively seek them out, settle herself in the middle of the group, and proceed to stroke her children gently with her whips for several minutes at a time. The babies would return this gesture. One female P. marginemaculatus had several groups of babies scattered through the enclosure and visited each of them. Young amblygygids would also show this amicable interaction with their siblings until reaching sexual maturity. Siblings approached each other and greeted each other directly by repeated stroking of their whips. The only signs of aggression ever seen during this time were very mild. Sometimes if an individual entered a tight group of other amblypygids, the members of the aggregation would show a slight threat display by opening their pedipalps. This was very brief, however, and soon led to stroking of the new individual. When a threatening disturbance occurred, young amblypygids would rapidly group together around their mother, often running underneath her. When the researchers put their hands into the cage to transfer a female and her offspring to a new one, she ferociously (and effectively) defended them by trying to stab the offending hand with her palp spines. In contrast, a hilariously ineffective attempt to arouse antipredatory behavior in the amblypygids (to test whether safety in numbers may be a reason for aggregation) involved the researchers placing an anole lizard in their cage. Neither species was perturbed by this and contrarily approached the lizard and explored every inch of it with their whips. Even a tiny, yearling P. marginemaculatus walked right up to it, stroked it for about five minutes, and then calmly walked away.

amblypygids and anole
Say what you will about amblypygids, but you have to admit that they’re, at the least, interesting animals. They give us a great example of the wide range of adaptations that arachnids possess and the variety of appearances they can take on, even if that appears to be a purposeful combination of the creepiest invertebrates on earth. Amblypygids, strange as they are, deserve to be loved and appreciated as much as any other animal does. I’m happy if this article brought even one person reading it a little further away from the disgust and fear that may have been felt in response to the first picture.

1. Harvey, Mark S. Catalogue of the smaller arachnid orders of the World: Amblypygi, Uropygi, Schizomida, Palpigradi, Ricinulei and Solifugae. CSIRO publishing, 2003.

2. Harvey, Mark S. “The neglected cousins: what do we know about the smaller arachnid orders?.” Journal of Arachnology 30.2 (2002): 357-372.

3. Pocock, R. I. “Arachnida.” The Fauna of British India, including Ceylon and Burma. London: Taylor and Francis, 1900. 100-131.

4. Rayor, Linda S., and Lisa Anne Taylor. “Social behavior in amblypygids, and a reassessment of arachnid social patterns.” Journal of Arachnology 34.2 (2006): 399-421.

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