Speaker 1: Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 2: Hey, welcome to Stuff to Blow Your Mind. My name
Speaker 2: is Robert Lamb.
Speaker 3: And I am Joe McCormick, and we're back with part
Speaker 3: two in a series we are calling Hunters of the
Speaker 3: Dark Ocean, focusing on predators that operate in deep marine
Speaker 3: environments and folks, full disclosure if we sound like we're
Speaker 3: broadcasting from the bottom of the sea ourselves today. I
Speaker 3: think Rob and I are both maybe operating at lower
Speaker 3: power than usual.
Speaker 4: I don't know. Do do you have a story here, Rob?
Speaker 2: Oh, just that I'm battling a cold and as of
Speaker 2: right now, all the cold medicine is like firing at
Speaker 2: full throttle.
Speaker 4: Oh nice, So we time to just right, Yeah, time.
Speaker 2: To just write. It may wear off halfway through and
Speaker 2: you need a listener and get to get to appreciate
Speaker 2: like a slightly gravelly sexier voice for me as we
Speaker 2: discussed various slimy creatures that live in the depths.
Speaker 3: Yeah, so I was up a lot last night. It's
Speaker 3: just childcare related lack of sleep.
Speaker 4: But hey, here we are.
Speaker 3: We're coming to you once again, folks. So brief recap
Speaker 3: on part one of this series. In the last episode,
Speaker 3: we kicked things off talking about the science news story
Speaker 3: that originally inspired us to look at this topic of
Speaker 3: deep ocean predators. That was a paper published last November
Speaker 3: in the journal Systematics and Biodiversity by Weston at All
Speaker 3: documenting a newly discovered genus and species of predatory crustation
Speaker 3: which is found in the Atacama Trench in the southeastern Pacific.
Speaker 3: The species was given the name del Sabella common chaka
Speaker 3: the Sugary Darkness. As we talked about, and oh boy,
Speaker 3: that really sent us down a rabbit hole of scrutinizing
Speaker 3: bizarre deep sea amphib body forms.
Speaker 4: It was a good time. Yes.
Speaker 3: We also talked a bit about the general challenges facing organisms,
Speaker 3: including predators that live in the deepest parts of the ocean,
Speaker 3: not just pressure, darkness, and cold, but also unique resource challenges.
Speaker 3: Since sunlight doesn't reach the bottom of the ocean, it
Speaker 3: is generally devoid of the primary photosynthetic organisms that form
Speaker 3: the base of the food chain at the surface. Instead,
Speaker 3: the deep ocean food chain tends to build off of
Speaker 3: a couple of things. First, chemosynthetic organisms like bacteria and
Speaker 3: archaea that feed off of hydrogen sulfide and other compounds
Speaker 3: from geological sources like hydrothermal vents, and then second dead
Speaker 3: organic material and detritus that rains down from the sun
Speaker 3: touched ocean above. This is sometimes called marine snow. It
Speaker 3: includes everything from fecal matter and tiny dead organisms sinking down,
Speaker 3: things sinking down of every ape and size. And we
Speaker 3: also talked about the fascinating temporary ecosystems that spring up
Speaker 3: around a big payload that falls from above, like a
Speaker 3: whale carcass when it hits the bottom and the abyssle
Speaker 3: or hatel zone.
Speaker 4: Yeah.
Speaker 2: And one of the things too that we were driving
Speaker 2: home in that episode, and we're going to continue to
Speaker 2: stress here and subsequent episodes, is that there is a
Speaker 2: great deal of biodiversity in these depths, and it basically
Speaker 2: runs opposite of what the prevailing theory was at one
Speaker 2: point that you would just see a steady decline in
Speaker 2: biodiversity down to nothing and there would just be no
Speaker 2: life in the ocean past certain depths. And we know
Speaker 2: that's not the case now, in part due to things
Speaker 2: like the marine snow, the whale falls and those hydrothermal
Speaker 2: environments as well, but also just in general, creatures that
Speaker 2: have evolved to thrive at depths that we used to
Speaker 2: think we're maybe just not possible.
Speaker 3: But anyway, back to recapping part one. After we talked
Speaker 3: about those general issues and talked about the predatory amphipod,
Speaker 3: we looked at a totally different order of oceanic predators,
Speaker 3: known as sciphonophores, and we discussed the fascinating way that
Speaker 3: their bodies are put together, the versions of these organisms
Speaker 3: that are as long as a whale as thin as
Speaker 3: a rail, catching prey in a sort of net made
Speaker 3: from their own bodies. And then we discussed how, despite
Speaker 3: most sightings of siphonophores occurring at less extreme depths, Rob
Speaker 3: you turned up some research that included probable sightings of
Speaker 3: predatory siphonophores at Haitel depths down within the Mariana Trench.
Speaker 3: That's right, and so today we're back to discuss more.
Speaker 2: Now before we jump back in with the predators, though,
Speaker 2: I want to just quickly discuss an example of a
Speaker 2: scavenging organism in the mid depths. A polyget worm called
Speaker 2: pobious messis, or simply the balloon worm as it's more practical,
Speaker 2: it's more common name, because it does look like a balloon.
Speaker 2: It has a small body, it's like one point five
Speaker 2: inches or thirty six millimeters long, and it kind of
Speaker 2: looks like I've seen it described as like a plastic bag,
Speaker 2: like a plastic bag that is filled with fluid. It's
Speaker 2: very translucent looking. And basically that marine snow. All of
Speaker 2: those bits of flesh, fish poop, and other organic detritus
Speaker 2: that just drifts down from the depths above. That's literally
Speaker 2: all this thing eats. And these things are quite abundant
Speaker 2: according to the Monterey Bay Aquarium Research Institute. They play
Speaker 2: a key role in cycling nutrients like carbon from the
Speaker 2: ocean's surface down into its depths. And also, no doubt
Speaker 2: these are the prey animals for various predators in the
Speaker 2: depths as well.
Speaker 3: Yeah, and that lines up with something we talked about
Speaker 3: in part one, where in these deep habitats a lot
Speaker 3: of the prey species being scavengers. So again we got this,
Speaker 3: you know, the kind of marine debris, organic debris of
Speaker 3: various kinds raining down from above. Then you've got the
Speaker 3: animals that scavenge off of that dead material, and then
Speaker 3: you've got the predators that come and eat those scavengers,
Speaker 3: and then perhaps also you may have predators that eat
Speaker 3: those predators. But certainly you have lots of predators that
Speaker 3: eat the scavenging things, scavenging things like amphipods that we
Speaker 3: talked about last time. So there is an animal that
Speaker 3: I want to bring up, a deep sea predator that
Speaker 3: I came across just kind of randomly, that I wanted
Speaker 3: to focus on for a bit, because yes, it looks weird,
Speaker 3: but it looks weird in a way that is biologically
Speaker 3: connected to some themes we've been exploring and will continue
Speaker 3: to explore some more. And that is an abyssle predator
Speaker 3: known as Hypnop's mead ee or the gridi fish. So
Speaker 3: that genus and species is spelled ip and ops and
Speaker 3: the species is mead. I I want to give a
Speaker 3: shout out to the place where I learned about this fish.
Speaker 3: It was in a mission log hosted on THEAA Ocean
Speaker 3: Exploration Hub from May twenty seventeen by an oceanographer named
Speaker 3: Astroid Lightner at the time of the University of Hawaii
Speaker 3: at Manoa. I looked her up, and I believe she's
Speaker 3: now affiliated with Oregon State University. But in this post,
Speaker 3: Lightner is talking about what she and a group of
Speaker 3: colleagues found during one particular exploration dive in the Central
Speaker 3: Pacific Basin, specifically a soft sedimented abyssle plane around what's
Speaker 3: called the Clipperton Fracture Zone at a depth of about
Speaker 3: forty four hundred meters. And just want to note that
Speaker 3: the overall expedition here, so this was one dive on
Speaker 3: a larger expedition. The overall expedition was called Mountains and
Speaker 3: the Deep exploring the Central Pacific Basin. And one cool
Speaker 3: connection here is that she's mentioning some of the other
Speaker 3: scientists involved in this dive, and one of them is
Speaker 3: a previous stuff to blow your mind guest Diva Aimon,
Speaker 3: who if Yeah, if you want to check out an
Speaker 3: interview that we did with a marine biologist who studies
Speaker 3: the deep sea, you should look up our episode with
Speaker 3: her in the back catalog. It's got to be well,
Speaker 3: probably five or six years ago now. But yeah, Diva
Speaker 3: Amon spelled Amo.
Speaker 2: N Oh, Yeah, she was great. The only guest we've
Speaker 2: had on the show I think that has actually personally
Speaker 2: been personally been down into the deep ocean.
Speaker 3: I remember that being a good episode. I enjoyed talking
Speaker 3: to her. But anyway, in this post, talking about this
Speaker 3: dive in the Pacific, Lightner is describing a survey of
Speaker 3: organisms that these researchers did over this kind of vast,
Speaker 3: relatively flat, sedimented patch of seafloor. Now, in the last episode,
Speaker 3: we were talking a good bit about the Hadel zone,
Speaker 3: like the deepest forty five percent or so of the
Speaker 3: ocean by depth if you're just looking vertically. Of course,
Speaker 3: the Haitel zone is limited to ocean trenches, so that's
Speaker 3: a small minority of the ocean's horizontal surface. Most of
Speaker 3: the ocean floor is not nearly that deep, and it's
Speaker 3: what we would normally call the abyssal zone. That's what
Speaker 3: we're looking at here is the abysstal zone, so not
Speaker 3: deep deep in the trenches, but still very deep. It's
Speaker 3: just the floor of most of the regular part of
Speaker 3: the ocean. And talking about this abyssal plane, Lightner says
Speaker 3: that these habitats have long been assumed to be what
Speaker 3: she calls biologically monotonous. I interpret that to mean you
Speaker 3: would expect to find roughly the same distribution of species
Speaker 3: all across them. But then she says, you know, really
Speaker 3: that was just sort of a guess. There were not
Speaker 3: enough observations of these habitats to know what life forms
Speaker 3: were there and if there were major variations in species
Speaker 3: throughout the space. So Lightner says that during this one
Speaker 3: dive that she's talking about the most abundant fishes they
Speaker 3: found on the seafloor. Here were the fish that I
Speaker 3: mentioned at the top of this segment, I knops Meade
Speaker 3: or the gridye fish. This was named after a twentieth
Speaker 3: century American ichthyologist and named it Giles Mead. And she
Speaker 3: says that they cataloged seven of these fish during one
Speaker 3: dive exploring the soft sediment, and that they're actually pretty
Speaker 3: easy to spot because of their huge, highly reflective eyes.
Speaker 4: Now you might be trying to picture them in your head.
Speaker 3: How reflective, How easy would these things be to spot? Well, Rob,
Speaker 3: I want you to weigh in here after looking at
Speaker 3: a picture in the outline.
Speaker 2: Oh wow, yes, that's rather distinctive.
Speaker 3: So the fish's body is long and tubel like with
Speaker 3: dark pigmentation. It appears to be gliding along the ocean
Speaker 3: floor right over the top of the sediment, but on
Speaker 3: the top of its head, So not really the front.
Speaker 3: It's like right down on the top, it looks like
Speaker 3: somebody has scooped out two little lima bean shaped depressions
Speaker 3: in the fish's skull. And then so if you imagine
Speaker 3: them together, like the flat sides of the lima bean
Speaker 3: shapes are facing inward touching one another. So like put
Speaker 3: two lima beans right next to each other with the
Speaker 3: flat sides together, and you scoop out that volume from
Speaker 3: the skull, and then you paint in the two scooped
Speaker 3: out regions with neon yellow glow in the dark paint.
Speaker 3: So it really does look like those toys I had
Speaker 3: when I was a kid, a little monster where you
Speaker 3: hold it up to the light bulb and then you
Speaker 3: turn the light off and it glows. Looks exactly like that. Now,
Speaker 3: this little guy might not look especially threatening given the
Speaker 3: Lisa Frank eyes, or I don't know, maybe it does
Speaker 3: look more threatening. I guess I'm sort of reminded of
Speaker 3: some kind of movie poster. I can't remember exactly what
Speaker 3: it is, but there's a monster that has eyes like this,
Speaker 3: just big, you know, undifferentiated neon yellow spots. But whether
Speaker 3: or not it looks threatening to you, this actually is
Speaker 3: a predator eating small abyssle crustaceans. And while I think
Speaker 3: its biology is not fully understood, it seems that these
Speaker 3: bony plate like neon bean cup eyes lack a lens
Speaker 3: and thus cannot resolve images. So it is seeing in
Speaker 3: a way, but it's probably not seeing images. Instead, these
Speaker 3: things are thought to only detect the presence or absence
Speaker 3: of light. They're more like light spots, and thus are
Speaker 3: probably designed by evolution to sense bioluminescence.
Speaker 4: From nearby prey.
Speaker 3: And I was thinking about this, and I think it's
Speaker 3: just so interesting the different ways that light as just
Speaker 3: a type of energy features throughout the trophic relationships. At
Speaker 3: the surface where there's plenty of sunlight versus at the
Speaker 3: bottom of the sea, light plays a role in the
Speaker 3: food chain in both places, but those roles are so different.
Speaker 3: So the surface light plays the primary energy role at
Speaker 3: the base of the food chain. Light from the sun
Speaker 3: powers photosynthesis and plants and other autotrophs, and that sets
Speaker 3: off the chain of eating that goes all the way
Speaker 3: up to the top predators. And then, in addition to
Speaker 3: its role as the base energy input on the whole system,
Speaker 3: it also provides probably the most important type of information
Speaker 3: that fast moving animals use to survive and negotiate predation
Speaker 3: relationships from either side of the predator prey relationship. So
Speaker 3: whether you're a predator or a prey animal on the surface,
Speaker 3: one of your main jobs is seeing other animals and
Speaker 3: in some cases avoiding being seen. It's all an information
Speaker 3: game based on reflected light from the sun deep at
Speaker 3: the bottom of the ocean. It seems that light is
Speaker 3: still a major energy input on the food chain because
Speaker 3: of course it powers the food chain up above at
Speaker 3: the surface, which then at some point rains down as
Speaker 3: the marine snow or the whalefall for the scavengers at
Speaker 3: the bottom of the ocean. But there is also at
Speaker 3: the bottom of the ocean a different energy input. You
Speaker 3: got the energy input from chemosynthetic organisms around like sea
Speaker 3: floor vents and things, and then also down in the
Speaker 3: abyssle or the hatel darkness. Light plays an important relationship
Speaker 3: in this information competition between predators and prey, but it's
Speaker 3: not reflected light from the sun that plays that role.
Speaker 3: It seems to be primarily bioluminescent light and the way
Speaker 3: that it contributes to that struggle for information advantage between
Speaker 3: predators and prey is a bit different.
Speaker 2: That's right. Yeah, it is that it's not a realm
Speaker 2: where there is no light, but the sort of like
Speaker 2: the rules of light have changed, the importance of light
Speaker 2: has changed. And so I guess you could look at
Speaker 2: the grid eye fish here as being an example of
Speaker 2: a case where evolution has just decided, you know, we
Speaker 2: can scale back on the eyes a little bit. We
Speaker 2: still need them, but we need them for just specific things.
Speaker 2: And the next example we're going to discuss is one
Speaker 2: that kind of goes in a different direction entirely with
Speaker 2: the eyes. It really feels more like a scaling up
Speaker 2: but also a hyper specialization of its ocular equipment.
Speaker 4: Tell me more.
Speaker 2: So, I'm going to warn you that this creature's common
Speaker 2: name does sound a bit ridiculous, and it may earworm
Speaker 2: you with a Beatles song. But we're talking about strawberry
Speaker 2: squid here. Strawberry squids forever so called for their red
Speaker 2: coloration as well as the little marks on their skin
Speaker 2: that really do look like the seeds of a strawberry.
Speaker 4: Oh, they so do.
Speaker 3: I mean, if you zoom in on the skin of
Speaker 3: this thing, it's uncanny how much it looks like a strawberry.
Speaker 2: Yeah, because sometimes you know the naming of these creatures
Speaker 2: that it can be a bit off and just you
Speaker 2: kind of have to squint a little bit to see
Speaker 2: it for yourself. But here's pretty spot on. Its scientific
Speaker 2: name is histiotouthis heteropsis, and the heteropsis gets more to
Speaker 2: the point here as it translates to different sight or
Speaker 2: different eye.
Speaker 4: Oh yes, okay, so this is the squid.
Speaker 3: If people have seen a picture of this before and
Speaker 3: the thing you didn't notice about it was the strawberry
Speaker 3: texture of the skin, you may have noticed the two
Speaker 3: wildly different looking eyes.
Speaker 2: That's right, almost kind of a I'm reminded of the
Speaker 2: whole sleep with one eye open thing, but it has
Speaker 2: like but they're both open, but they're just different sizes
Speaker 2: and they see in different ways. It's pretty amazing.
Speaker 4: It's like the christ pantocrater.
Speaker 2: So, according to the Monterey Bay Aquarium Research Institute, our
Speaker 2: strawberry squid here reaches a maximum mantle length of teen
Speaker 2: centimeters or five inches, and its habitat is the midwater
Speaker 2: region of the twilight or mesopelagic zone, so we're talking
Speaker 2: the upper portions of the ephotic zone, the dark ocean,
Speaker 2: but the dark ocean. Nonetheless, However, the strawberry squid may
Speaker 2: reach depths of three thy three hundred feet during the day,
Speaker 2: but then migrates to shallower waters at night.
Speaker 3: Okay, and so we've talked about organisms like this before.
Speaker 3: I mean, one great example being the sperm whale that
Speaker 3: operates at in radically different light regimes at different parts
Speaker 3: of of its sort of feeding cycle. Like it might
Speaker 3: come up to shallow waters, of course, the whale would
Speaker 3: have to come up to the surface to breathe, but
Speaker 3: then it dives very deep into the dark in order
Speaker 3: to feed. And this would be another type of organism
Speaker 3: that goes a little bit more up into the light
Speaker 3: zone and then down into the darker zone.
Speaker 2: Right right. But of course, unlike the sperm whale, and
Speaker 2: the sperm whale does at different phases of its life
Speaker 2: have to deal with predation. But this critter is more
Speaker 2: like your common housecat, being both predator and prey at
Speaker 2: all times. You know, not so much in the confines
Speaker 2: of your house, but in the confines of the natural world.
Speaker 2: So there are two properties that are especially revealing here
Speaker 2: with this organism regarding life in the deep. First, I
Speaker 2: want to talk about a little bit about its strawberry
Speaker 2: coloration and as well as the seeds. So again those
Speaker 2: are not seeds. Obviously, those little marks on its red
Speaker 2: flesh are bioluminescent photophores. Those are light emitting organs. Now,
Speaker 2: in general, cephalopods use photophores for different forms of camouflage
Speaker 2: and antipredation, and they can pop up in various locations
Speaker 2: on the cephalopod body plan. But for the strawberry squid
Speaker 2: here they're on the outer skin and the purpose here
Speaker 2: does qualify as anti predation.
Speaker 3: Okay, so that's kind of hard to understand because you
Speaker 3: would think that you would think that lighting up your
Speaker 3: body would attract predators, not repel them.
Speaker 4: So how does this work?
Speaker 2: That's right, Well, we have to remember that this is
Speaker 2: the twilight zone. Some light does make it down this
Speaker 2: far during the day, and if something is looking up
Speaker 2: at you from beneath, it will see your outline against
Speaker 2: that filtered light. If you put in like sci fi
Speaker 2: film setting, imagine a starship, large starship powered down. It's
Speaker 2: just a dark form, but it's moving against the stars,
Speaker 2: and with a keen eye, you might notice that when
Speaker 2: you might think, well, if you wanted to disguise your
Speaker 2: powered down vessel, if you were to cover it with
Speaker 2: little shiny stars, well, that might help mask your appearance.
Speaker 2: That it might allow you to blend in to the starfield.
Speaker 2: And that's sort of what's going on with the strawberry
Speaker 2: squid here. It uses its bioluminescence to mask itself against
Speaker 2: to blend in with the filtered down light from above
Speaker 2: against predators below. I have a quote here that explains
Speaker 2: this general adaptation. This is from a nineteen eighty three
Speaker 2: text by Richard Edward Young titled Oceanic Bioluminescence and Overview
Speaker 2: of General Functions. He writes, quote, this function is the
Speaker 2: only one for which we have substantial experimental data. The
Speaker 2: hypothesis is an old and simple one. Dahlgren nineteen sixteen
Speaker 2: suggested that blue light from the ventral photophores and squids
Speaker 2: would cause these animals in deep water to blend with
Speaker 2: the sunlight when viewed from below. The process that allows
Speaker 2: a mesopolagic animal to eliminate its silhouette with bioluminescence and
Speaker 2: thereby conceal itself requires a very sophisticated mechanism. In the
Speaker 2: animals that utilize it.
Speaker 4: Well.
Speaker 2: For maximum effectiveness, they must precisely match their luminescence to
Speaker 2: the intensity, angular distribution, and color of the downwelling light.
Speaker 2: For those that counter illuminate in near surface waters at night,
Speaker 2: where the flight field is much more variable than in
Speaker 2: deep water, the mechanism must be especially complex.
Speaker 4: Wow.
Speaker 3: So it's almost like what we see in the movie
Speaker 3: Predator in a way where you know the predator's invisibility.
Speaker 3: Cloak seems to be a way of kind of projecting
Speaker 3: an image of the light patterns from behind the alien
Speaker 3: onto the front facing side of it, so that when
Speaker 3: you're looking at it, it's it's like a movie screen
Speaker 3: showing you what you would expect to see if the
Speaker 3: thing were not there from the from the backside. It
Speaker 3: might not have to be that exact with with like
Speaker 3: outlines and images in the case of the squid, but
Speaker 3: it does need to very closely match the light intensity
Speaker 3: and the color patterns and angular distribution of the light
Speaker 3: that would be coming down from above otherwise.
Speaker 2: Yeah, So to humanize this sort of light show, it
Speaker 2: may not be as as impressive as watching say a
Speaker 2: cuttlefish or some other you know an or or some
Speaker 2: sort of you know shallow water octopus blending in when
Speaker 2: it's environment with its camouflage. But it is a complex act, nonetheless,
Speaker 2: So it isn't just a matter of like, let's just
Speaker 2: throw some stars up there on your hide so that
Speaker 2: whatever's below can't can't make you out. Like. It's more
Speaker 2: nuanced and it's about hitting the right light intensity at
Speaker 2: all times. Now, that strawberry red coloration, that's a little
Speaker 2: bit more straightforward, but it reveals another curious relationship with
Speaker 2: light in the deep. This is one we've touched on
Speaker 2: before in the past, and it is red. The color red,
Speaker 2: maybe the color of caution. And notice on the surface,
Speaker 2: you know, it is the color you might wear to
Speaker 2: a wedding if you want to attract attention that sort
Speaker 2: of thing. It is the color of it's a flashy color.
Speaker 2: It's a sports car color, right, But in the depths
Speaker 2: it's a stealth color. And that's because red light doesn't
Speaker 2: filter this far deep, and so red organisms appear quite
Speaker 2: black in the natural illumination i e. Not like submarine illumination,
Speaker 2: thus further cloaking the organism here in question from predators,
Speaker 2: but in a more passive way.
Speaker 3: I see, so like it's because the longer wavelengths of
Speaker 3: visible light don't make it as deep in the water,
Speaker 3: so the red, the more red colors just don't really
Speaker 3: get reflected. Everything's kind of blue shifted down there.
Speaker 2: Yeah. But finally we have to talk about the strawberry
Speaker 2: squid's eyes and greater depth here. It does have very
Speaker 2: weird eyes again, different sizes, one big tubular and yellow lensed,
Speaker 2: and this is to keep an eye out above for
Speaker 2: the shadows of prey moving through dim waters, and then
Speaker 2: there's this much smaller specialized eye to keep an eye
Speaker 2: out below for bioluminescence of potential predators.
Speaker 3: So it's looking for shadows that it wants to eat
Speaker 3: and glowing things that want to.
Speaker 2: Eat it, yes, exactly. And it's I mean, it's really
Speaker 2: hard to think about this in terms of like the
Speaker 2: human perspective, because I mean you might imagine, like, what
Speaker 2: if I had one eye to see really well in
Speaker 2: the day and one eye that would see really well
Speaker 2: in the night, well sort of, And in fact, there
Speaker 2: were older theories that that's what was going on here,
Speaker 2: that this squid had two different eyes, one for when
Speaker 2: it was at lower depths, in one when it was
Speaker 2: a greater depths. But this would only work. This human
Speaker 2: example would only work if you were living in the
Speaker 2: sort of environment that this creature lives in, in which
Speaker 2: you were on the threshold of darkness and light pretty
Speaker 2: much at all times.
Speaker 3: Yeah, I mean, in a way, we do have eyes
Speaker 3: that can function in high and low light conditions because
Speaker 3: we have adjustable size, Like we can adjust the aperture
Speaker 3: of the pupil, so you know, they contract and when
Speaker 3: there's a lot of light and dilate when there's less light.
Speaker 4: But this is fit.
Speaker 3: Yeah, this is squid is in a different situation than
Speaker 3: we are because we are almost never in a situation
Speaker 3: where we need to be looking in one direction where
Speaker 3: there's more light and in another direction where there's less light. Also,
Speaker 3: we have been knock killer vision, so generally we're looking
Speaker 3: in the same direction with both of our eyes to
Speaker 3: get a perception of depth. Instead, the squid really has
Speaker 3: eyes on the back of its head whichever way you
Speaker 3: look from, and one way needs to be looking toward
Speaker 3: the sky and the other eye needs to be looking away.
Speaker 2: Yeah. Another imperfect way of thinking about this would be
Speaker 2: like if you had a human with one normal eye
Speaker 2: and then one eye that was essentially blind but saw
Speaker 2: really well into the astral plane, ever on the lookout
Speaker 2: for astro zombies that are coming to try and kill you.
Speaker 2: So these eyes apparently differentiate as the squid enters adulthood,
Speaker 2: distorting the shape of the head to accommodate the larger
Speaker 2: upward gazing eye. And the dimorphism is because it's a
Speaker 2: creature again with an eye and two realms of light
Speaker 2: at the same time. And I was reading a bit
Speaker 2: more about this. Thompson, Robinson, and Johnson explored the creature's
Speaker 2: asymmetric vision in a twenty seventeen paper published in Philosophical
Speaker 2: Transactions with the Royal Society b. They point out that
Speaker 2: the dim to dark mesoplagic region of the deep sea
Speaker 2: boasts the highest diversity of visual adaptations in the sea.
Speaker 2: A lot of evolutionary energy has to go into scraping
Speaker 2: out a survival story in this region, dealing with bioluminescence
Speaker 2: below and filtered sunlight above, but it is quote a
Speaker 2: fertile environment for eye evolution. Now we mentioned that that
Speaker 2: upward gazing eye has a yellow linb and they point
Speaker 2: out that this may be used to break up the
Speaker 2: counter illumination camouflage of their prey. They found it in
Speaker 2: sixty five percent of the specimens that they looked at.
Speaker 2: Yellow lenses are apparently common in upward looking deep sea
Speaker 2: organisms as well, like in fish, because they're thought to
Speaker 2: quote break counter illumination camouflage by enhancing spectral differences between
Speaker 2: down welling sunlight and bioluminescent camouflage. So it's geared at
Speaker 2: deciphering the very sore of counter illumination CAMO camouflage that
Speaker 2: it itself uses.
Speaker 3: Mm okay, So it's like it simultaneously is wearing a
Speaker 3: kind of lead shielding and X ray glasses.
Speaker 4: Yeah.
Speaker 2: They point out that body posture is also key. They
Speaker 2: position themselves with their head and arms downward, with the
Speaker 2: posterior mantle pointed upward in a vertical posture, and this
Speaker 2: ensures that they're pointing their photophores downward again to cast
Speaker 2: that counter illumination spell. And I think it's just such
Speaker 2: a fascinating example of a form that has evolved to
Speaker 2: thrive in a delicate environment. So their predators include various
Speaker 2: sharks and also even whales. And as for what they
Speaker 2: themselves prey upon, stomach contents suggest a mix of fish,
Speaker 2: other squid as well as crustaceans strawberry squids forever.
Speaker 4: Let me take you.
Speaker 2: Down all right now. The next deep sea organism I
Speaker 2: want to talk about is the fin deep sea octopuses
Speaker 2: of the genus Grimpotothus, commonly referred to as Dumbo octopuses
Speaker 2: because I mean, well, just look at them. Included a
Speaker 2: couple of images here for you, Joe. They're adorable and
Speaker 2: they boast earl like fins that remind many of Dumbo,
Speaker 2: the flying elephant.
Speaker 3: They look tremendously like Dumbo. Yes, extremely cute and with
Speaker 3: big floppy ears and almost yeah, I kind of elephantine
Speaker 3: shape to their lumpy head body mm hmm.
Speaker 2: Sometimes the position of their arms also kind of reminds
Speaker 2: one of a trunk or trunks, like it's some sort
Speaker 2: of weird multi trunk elephant, that sort of thing. So
Speaker 2: the Dumbo octopuses, they're members of the Serena suborder of octopods,
Speaker 2: who are notable for having evolved away from jet propulsion
Speaker 2: in favor of fin propulsion. So if you've ever consumed
Speaker 2: any cephalopod a media, or you know, learned about them
Speaker 2: in the past, you know that I think squid are
Speaker 2: some of the more fabulous examples of this. They use
Speaker 2: jet propulsion. They take they they take in a bunch
Speaker 2: of of water and then they jet it out to
Speaker 2: push them along through the water, often at you know,
Speaker 2: nice high speeds.
Speaker 4: Well marine rockets, yeah.
Speaker 2: Little marine rockets. Uh. These octopods, however, have jettison back.
Speaker 2: They also tend to lack anal flaps and ink sacs,
Speaker 2: so they can't jet ink, which is another common self
Speaker 2: defense mechanism of cephalopods being able to just squirt out
Speaker 2: that cloud of ink and make a quick escape.
Speaker 4: Yeah, it's like the it's like the Batman, you know,
Speaker 4: smoke escape pom. Right.
Speaker 2: And they also lack chromatophores, so they can't adjust their coloration.
Speaker 2: They can't do any kind of blending in with their
Speaker 2: environment other than what their uh, their their natural coloration
Speaker 2: is all ready providing. Okay, their arms are web together,
Speaker 2: which also earns them the informal name of umbrella octopuses.
Speaker 4: Oh well, that's just adorable.
Speaker 2: So what we have then, is as a bunch of
Speaker 2: creatures that seem to have just abandoned most of like
Speaker 2: the really expensive, evolutionarily speaking, self defense mechanisms that their
Speaker 2: can have evolved in favor of a more just sort
Speaker 2: of drifting, leisurely existence. Now why would that be, Well,
Speaker 2: it has everything to do with how deep they actually reside.
Speaker 2: They reside at extreme depths of at least thirteen one
Speaker 2: hundred feet or four thousand meters, putting them squarely in
Speaker 2: the abyssopal agic zone, so way down there, not quite
Speaker 2: into the Hadel but still pretty turned deep like way
Speaker 2: like in a way, we keep mentioning the Hadel zone
Speaker 2: as being like, this is the extreme, this is where
Speaker 2: the real depth happens. But no, the Hadel zone is
Speaker 2: just that extra topping on the invert did cake here
Speaker 2: and everything is already just crushingly deep before we reach
Speaker 2: that threshold.
Speaker 4: Yeah.
Speaker 3: Us talking about the ocean trenches was not to suggest
Speaker 3: that the horizontal surface of most of the bottom of
Speaker 3: the ocean is not that deep. It is the regular
Speaker 3: abyssle zone is deep.
Speaker 2: So what are the dumbo octopuses eat? Well, first of all,
Speaker 2: they're not that big, eight to twelve inches in length,
Speaker 2: and here in the depths they foread for pelegic invertebrates
Speaker 2: generally close to the seafloor in the area that they're thriving,
Speaker 2: but they don't. It's important to note they don't like
Speaker 2: crawl around seemingly on the seafloor like like other octopods
Speaker 2: are observed to do. They live, you know, in the water.
Speaker 2: They do go down to the sea floor as well, though,
Speaker 2: to lay their eggs, generally on deep water corals. But otherwise, yeah,
Speaker 2: they're free swimming, dreamy floaters in the depths that have
Speaker 2: you know, cast aside all of their evolved andry. And
Speaker 2: it's because you know, they don't seem to have to
Speaker 2: deal with that many predators. They do have predators, you know,
Speaker 2: generally diving predators from above, but it seems that they
Speaker 2: likely lost their various costly defense mechanisms because they thrive
Speaker 2: in a rather depopulated region of the deep.
Speaker 3: Okay, And this is a type of adaptation that we've
Speaker 3: seen in other animals and other ecosystems, where you know,
Speaker 3: you can lose a lot of your defenses if you
Speaker 3: just adapt so that you are able to thrive in
Speaker 3: a difficult environment where they're not a lot of predators.
Speaker 2: Yeah, it reminds me in an imperfect way, I'm sure
Speaker 2: of when I was a kid, I would look at
Speaker 2: all these airplane illustrations and sketches, you know, and like
Speaker 2: the er some of your higher altitude planes they often
Speaker 2: had like really like cool looks, you know, like the
Speaker 2: SR seventy one Blackbird or you know, various strategic bombers
Speaker 2: and all. But then when you get to the U two,
Speaker 2: which is a very very high it was you know,
Speaker 2: a very high altitude spyplane. You know, it looks looks
Speaker 2: a little dumb, and it just has really long wings,
Speaker 2: but it's you know, it's it's altitude was its defense.
Speaker 2: And in a sense, this is this is kind of
Speaker 2: like the inversion of that, like its depth is its defense,
Speaker 2: and therefore it doesn't need, you know, to look crazy.
Speaker 2: It doesn't need to you know, have a bunch of
Speaker 2: guns on it or in this case, you know, it's
Speaker 2: various octopid defense mechanisms. Now, their reproductive systems also speak
Speaker 2: to their isolation, and we see this in other organisms.
Speaker 2: We're going to discuss another one, I think in the
Speaker 2: next episode. If you're if you're thriving in an area
Speaker 2: where there's just you're basically in a desert, well you're
Speaker 2: you're not going to run into potential mates as much either.
Speaker 2: I mean, you're not going to run into foes, but
Speaker 2: you're also not going to run into potential friends. So
Speaker 2: a female keeps multiple eggs in various states of development
Speaker 2: inside of her body, and she can also store sperm
Speaker 2: for extended periods of time as well, thus making the
Speaker 2: most out of these infrequent encounters with the opposite sex. Furthermore,
Speaker 2: the mother doesn't stay with the eggs once they've been laid.
Speaker 2: According to a twenty eighteen article by Shay at All
Speaker 2: in Current Biology, the young here hatch as fully confident juveniles,
Speaker 2: so a newly hatched dumbo octopod can immediately begin carrying on,
Speaker 2: feeding and so forth like any adult born.
Speaker 4: Ready.
Speaker 2: Yeah, so I love these guys. I mean they're weird looking,
Speaker 2: They're definitely weird, But their weirdness is one of isolation
Speaker 2: and a casting off of defensive adaptation speed ink camouflage,
Speaker 2: because they've adapted to live so deep, not so deep
Speaker 2: that they can't be found by predators, but seemingly such
Speaker 2: predation is just far less common. However, it is stressed
Speaker 2: in some of the literatures looking at that they do
Speaker 2: deter predators by ballooning up. That's one thing that they
Speaker 2: kept like they can balloon up their bodies and their
Speaker 2: umbrella arms to appear larger than they actually are. This,
Speaker 2: of course, is a common anti predation feature, and so
Speaker 2: they've they've held onto that one. That's one that they
Speaker 2: I guess it's not too costly from an evolutionary standpoint,
Speaker 2: and they can keep that one for when they need it.
Speaker 3: But in the case of this animal, that just sounds adorable. Look,
Speaker 3: I'm big and scary.
Speaker 2: Yeah, indeed, how big and scary could they? Could they
Speaker 2: end up looking? Yeah, it seems like that's, you know,
Speaker 2: kind of like a last ditch defense mechanism. But for
Speaker 2: the for the most part, it's just I'm so deep,
Speaker 2: you're probably not gonna find me. The odds are with
Speaker 2: me that you can't find an eating all right, Where
Speaker 2: We're gonna go ahead and close out this episode of
Speaker 2: stuff to blow your mind, but we're gonna be back.
Speaker 2: We have more to discuss in our look at dark
Speaker 2: ocean predators, you know we have. We're gonna get back
Speaker 2: to a creature we mentioned in passing in the first episode,
Speaker 2: and I believe next episode is also going to be
Speaker 2: the one where I get to discuss one of the
Speaker 2: deep sea predators that are or if you've probably thought
Speaker 2: up any like when are they going to talk about
Speaker 2: this one? Well, the next episode is probably the episode.
Speaker 2: In the meantime, Yeah, write in, We'd love to hear
Speaker 2: from you. Just a reminder that Stuff to Blow Your
Speaker 2: Mind is primarily a science and culture episode, with core
Speaker 2: episodes on Tuesdays and Thursdays, short form episodes on Wednesdays
Speaker 2: and on Fridays. We set aside most serious concerns to
Speaker 2: just talk about a weird film on Weird House Cinema.
Speaker 3: Huge thanks as always to our excellent audio producer JJ Posway.
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