Friday, October 11, 2013

Salamanders, Buoyancy, and Loch Ness

My thanks to Christopher Hjelte, a reader of this blog who recently sent me a link to an interesting video about research into axolotls at Blackburn College in Carlinville, Illinois.  Midway though this 2 minute piece, we learn of a very odd and previously undocumented behavior first observed and later filmed by Blackburn students studying these aquatic salamanders.  A behavior that might possibly bear some implications for surface sightings of much larger cousins elsewhere!

https://www.youtube.com/watch?v=OLwQpU0Ga80&feature=youtube_gdata_player

Like most obligate-aquatic salamanders (that is, those salamanders with no terrestrial phase to their life cycles) axolotls (Ambystoma mexicanum) have retained their lungs, although as the video points out the utilization of these lungs hasn't seen much prior study.  While it's true lungs are the norm for aquatic salamanders, including the giant Cryptobranchidae, all these species primarily breathe through cutaneous respiration, absorbing oxygen from the water through their skins.  Furthermore,  the really neotenic forms such as axolotls normally retain their larval gills for life, thus giving them not one, not two, but three methods of respiration.  At first that seems like a bit of evolutionary over-kill, so I've trundled a bit down a line of research I'd been away from for awhile.

While they may never need their lungs for respiration while in water, the Blackburn research shows that axolotls sometimes inhale one gulp of air and hold onto it, apparently for the sole purpose of floating on the surface -- albeit they float upside down!  This orientation doesn't seem to bother them (perhaps no one has embarrassed them yet by telling them just how adorable it looks).  Their lungs must be located below their center of mass, not that this would matter under other circumstances.  But given that they have this ability to float, we can wonder why they choose to do so in the first place.

And to quote Mr. Hjelte, "Up turned boat, anyone?"


"FLOATERS" IN THE LOCH?

This leads back to one of the most important points I made in my previous article on surface sightings, and what they can tell us about the morphology of the Loch Ness Giant Salamander.  And this is equally applicable when observing any aquatic animal partially extruded on the water's surface:  animals that live in a three-dimensional, "weightless" environment, can and will float and swim in positions that are independent of our terrestrially biased, two-dimensional thinking.  Any aquatic animal can float head down and tail up, or at any angle, or list to either side, for any reason that suits it.  And in the case of at least one species of small, aquatic Mexican salamander, we now see that even upside-down surface floating is normal!

So it's behavior as well as morphology that determines what an eyewitness would see at Loch Ness, if any deep-living animal pays a rare visit to the surface.  Roy Mackal grappled with the problem of the Nessie's back contour, and the issue of multi-hump and variable hump sightings.  Eels at first seemed to be a problem candidate, as they have laterally flattened bodies and swim by sinusoidal flexure (side to side, not up and down).  Then he tells the story (in The Monsters Of Loch Ness, 1976, page 150) of having a revelation on this point while observing eels at Chicago's Shedd Aquarium:

"Eels occasionally swim on their sides, and when doing so at the surface, the series of undulations appear to the observer as vertical by virtue of the fact the animal is on its side.  This motion can easily produce a violent splashing of water at the surface and a series of humps above the waterline."

He received corroboration from Maurice Burton, who observed the same side-swimmng eel behavior at the London Zoo.  Alas, on my own visits to the Shedd, I've never stayed with the eels long enough to observe such delightful behavior, but then there's just so much to see there.

This is one example of how a seemingly incompatible morphology, in this case that of eels, can account for an observation, in this case vertical humps, once three-dimensional behavior is taken into account.  Or as I stressed in my previous article, the appearance of a long neck on a short-necked animal if it's floating with it's tail elevated above water.  Incidentally, on that trip to the Shedd, Mackal observed an eel floating vertically, head down, with it's tail sticking up straight out of the water as well!  (For the record, at that time Mackal still favored the variable dorsal contours of a giant amphibian as better accounting for the observational data from Loch Ness, even as he made these points about eels.  Salamanders will often float with their backs arched at a fairly acute angle, the degree of which would most readily account for both triangular humps on one hand, and the frequently observed upturned-boat effect on the other.)

So now, what can we say about this matter of belly-up "floaters" as it relates Nessie?  Yes, it's another way to explain the upturned-boat effect, but the dorsal profile the Loch Ness Giant Salamander has that accounted for already.  Personally I doubt it occurs, but to say it never occurs would make me guilty of two-dimensional thinking.  The animal will float as it pleases regardless of any human opinions.  The possibility does offer us a couple tidbits.

Criticism in the variation of reported details from sighting to sighting and from witness to witness have lead some to conclude there cannot be a real, unrecognized animal behind any of these observations.  I actually take exception with that, and would note the consistencies far outweigh inconsistencies.  Be that as it may, there has been noted variability in the reports regarding skin color, skin texture, and the lack or presence of a dorsal ridge.  The variability of the latter is already accounted for in my working morphology, depending on whether the hump is viewed from front or back.  However, if there are witnesses insisting there's a dorsal ridge running the whole length of the spine (I vaguely recall an instance or two where this might be mentioned), then smooth-back sightings would still be explainable by the belly-up floater.  I doubt we have to stretch anything that far though.  And Dinsdale solved the skin texture problem in terms of viewing conditions and distance long ago, without need to resort to flipping the beast over!

What is key here is that, as is typical of aquatic salamanders, we should expect Nessie to not only have lungs, but to occasionally use them.


ONCE IN A VERY GREAT WHILE

One obvious but secondary use for those lungs would be respiration when out of the water.  One must assume this is a secondary function, because land sightings of the Loch Ness Giant Salamander are so rare as to be almost non-existent.  But then, for all known species of aquatic salamanders, leaving the water is also extremely rare, even though we've long known (through dissection) that they certainly have functional lungs.  (In fact among all extant amphibians in all four orders, lungs are only absent in one clade of salamanders, the plethodontids, which are minute and terrestrial, and in two species of caecilians.  Lungs are of course present in frogs, but even the primitive and aquatic sirens have retained functional lungs.)

To avoid hypoxia, aquatic salamanders do indeed stick their heads out of the water and use their lungs for respiration, a life-saving backup plan should the oxygen content of the water become too low.  This however would not be a factor in the cold and highly oxygenated waters of Loch Ness.  Although perhaps even in Loch Ness, an amphibian might need to gulp auxiliary oxygen following some unusually aerobic activity -- courtship behavior among salamanders can be extremely demanding.


NOW TAKE A DEEP BREATH...AND HOLD IT

But the primary use of lungs observed in aquatic salamanders is buoyancy control.  Inflated lungs serve as hydrostatic organs and allow for continuous floating at either the surface, or a desired depth, with little or no expenditure of energy.  This could not otherwise be achieved because, unlike ray-finned fish, amphibians have no swim bladder.

What they do have though is a specific gravity greater than one (1), which means they sink to the bottom.  (Objects with a specific gravity of 1 are neutrally buoyant in water, those with a specific gravity greater than 1 are denser than water, and so will sink in it, and those with a specific gravity of less than 1 are less dense than water, and so will float.  The number is calculated by dividing mass by volume.)

So in many cases, the lack of hydrostatic control would prove lethal.  Axolotls might not need it as much as other species, as the video above seems to imply they are amateurs at it.  Their relatives, the tiger salamanders, depend on it, at least in their larval stage. Tadpoles of the tiger salamander need to float overnight at a specific depth, rather high in the water column, in order to feed on Daphnia, which is all they can eat at that stage.  But they have a specific gravity greater than 1, which would leave them either trapped on the bottom or paddling to maintain "altitude" all night, expending more energy than they might take in from feeding.  The solution is to swim to the surface, inhale just enough air to lower their specific gravity to exactly 1, then swim to the desired depth where they can float all night, and gorge themselves without burning more calories.  Come morning they release the air, and sink to the bottom to hide in safety.  Once they become much larger, terrestrial adults, capable of larger prey, they still continue this behavior anyway because they seem to just plain like the Daphnia.

So it seems the regulation of buoyancy may be the primary reason aquatic salamanders retain their lungs for life, although that ability to breathe surface air does occasionally come in handy under extreme or unusual circumstances.  But while in well oxygenated water, they don't need to exhale because they are still getting their oxygen via cutaneous gas exchange.  They hold only the air they want to maintain the buoyancy they want, and for as long as they want.  Hydrostatic regulation of this sort has been observed in many salamanders, including the Cryptobranchids, and is no doubt utilized by all salamanders.  This alone was reason enough for evolution to retain lungs in aquatic salamanders no matter how little else they might use them.

All of which of course has profound implications for strange things seen in Loch Ness, if the cause were a giant salamander.

Smooth vertical submersions without a noticeable disturbance of the water would be expected, as that's the normal exit for floating salamanders.  And that is the most oft reported exit Nessie has been reported to make.  That would most likely be a planned return to the very bottom of the Loch, where these animals spend the majority of their time.  One wishing to keep it's air to maintain a specific gravity of 1 (to cruise at a certain depth) would of course have to swim down, which would occasionally result in some splashing.

Also riding too high in the water,  frequently a critique of some reports, and especially of the Hugh Gray photograph, should be less of an issue knowing that a specific level of buoyancy is actually under control of the animal itself.  A hump two feet above water may not require as gargantuan an animal as one would think.

Juveniles, surfacing for the first time might even experience some trouble getting used to their lungs, as they will be taking their first breaths.  And they could already be of substantial size at an early age.  The axolotls may only have trouble floating right-side up,  but other salamanders have been observed rolling on taking in air on their first tries, because only one lung inflates on the first go, listing them over to float sideways, and when they try to compensate with paddling they send themselves into a little spin.  (In Nessie's case, "little" might be the wrong word.)  Eventually they learn they need to exhale, relax, and try again.  The belly-up axolotls at Blackburn College may be forgetting to exhale, stranded on the surface like a kitten stuck up the first tree it's ever climbed and wondering how to get down.  Apparently hydrostatic regulation in salamanders takes a little practice to get right!  Would that a Loch Ness Giant Salamander were to get stuck on the surface for a nice long sighting, although you might not want to be in a small boat close by while it was rolling, thrashing, and trying to figure things out.

Of course hydrostatic regulation is a very useful skill.  The main supply of fish in Loch Ness are not at the bottom, they are found in the shallower waters, the littoral regions.  Incessant swimming to maintain the right depth would be extremely costly to a predator, and salamanders are extremely stingy about spending energy to hunt -- they don't chase, they lurk.  This gives Nessie its reason to climb to the surface, taking in just enough air to establish specific gravity 1, so it can swim down and maintain station effortlessly when it wants to feed at the depth of the prey, if that is indeed its preferred method of feeding.

Notably, inflated lungs would show up on sonar, but unless the animals regularly held onto extra air during a forced dive they would return a much weaker echo.  Which means you might get a strong contact one day, but not again for a very long time.

Much of this will sound very, very familiar to those who have looked at data and sighting reports from Loch Ness.  There may be a very good reason for that.

12 comments:

  1. Dear Mr. Plambeck :

    Let me introduce myself as a new reader to your Blog site. I find your theory of a giant salamander intriguing, not that it hasn't been suggested before by other researchers. F.W. Holiday proposed a giant aquatic worm or Tullimonstrum even a paranormal explanation. The list of suspects runs the gamut from giant long necked seal, eel, sturgeon, the proverbial Plesiosaur etc., so why not a giant salamander. I’m open to any possibility at this point, until proven otherwise, well, maybe not a time portal/dimensional creature. I’ve just scratched the surface of your site, but what I can see so far is a well laid out researched and detailed document, it makes for good reading.This Blog should serve as an excellent adjunct and companion site to Roland Watson’s popular Blog as an alternative explanation to the Holy Grail of Cryptids. The LNM mystery is one of high strangeness. Thank you and keep up the good work.

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    1. Thanks and welcome to the Blog. The salamander theory is indeed old, first proposed by W.H. Lane long ago -- his story is one you'll encounter in an older part of this site, and Roland has written about Lane as well. Ivan T. Sanderson called the theory "not totally illogical" (in his forward to Holiday's 1968 book), and naturalist Rupert T. Gould also suggested a giant salamander at one time. More famously perhaps, a giant amphibian was also Mackal's initial conclusion in 1976, although in later years he considered a mammalian explanation - still does as far as I know. While the idea always seemed to become abandoned and gathered dust a long time, I obviously think it's always been the correct answer, and the goal of this blog is to demonstrate why. Definitely more writing ahead, so please enjoy.

      Steve

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    2. Hi Steve, and thanks for the mention! Glad to be of some sort of input. Indeed, this here video as well regarding the Ambystoma genus, is at least to me of great interest. It theorizes on the fact that while some neonates "choose" to remain in that state of developement, others don´t. Maybe due to some unexplained sixth sense, as suggested in the video. Hope you find it interesting! Cheers from Sweden! //Christopher Hjelte http://www.youtube.com/watch?v=asOCVEAwsCA

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    3. Hi Christopher, and thanks again as well.

      The documentary at http://www.youtube.com/watch?v=asOCVEAwsCA covers one year in the life cycles of the fauna in the Colorado wetlands, for those interested in the broader subject. But at 2:50 into the video, it gets very interesting indeed when we learn that tiger salamanders can apparently suppress metamorphosis in response to changes in the terrestrial environment, even though they've never been out of the water to see what's going on. (Unlike their closest relatives, the permanently aquatic axolotls, tiger salamanders normally morph into a terrestrial form after a few weeks growth.) At least it was observed in this particular pond this season, and the film maker wonders if the construction of a quarry nearby might have something to do with these tadpoles deciding to stay tadpoles.

      I immediately thought of the blasting and construction that went into the A82 on the north shore of Loch Ness in the 1930's, and the increased auto traffic that's ringed the shores ever since then.

      It's tempting to speculate that a giant neotenic salamander species in Loch Ness might do as the tiger salamanders, sticking with a more juvenile state than they would have before all the noise started, and remaining in the water for life. The flurry of land sightings in the 30 years subsequent to the A82 could represent the specimens that had already matured before construction began (land sightings indeed pre-date the A82), specimens that consequently had more developed limbs and terrestrial urges.

      By the 1960's, when land sightings become almost non-existent, those older specimens might have died off, while the younger ones, aware of the traffic noise before they faced metamorphosis, "chose" to skip it. As legend has it, Nessie is hypersensitive to noise. Doesn't that add up nicely? :)

      Too nicely, and in fact 180 degrees opposite something else I've been writing. I'll have to incorporate this new possibility.

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  2. Thanks Steve, useful info on oxygen supply and bouyancy.

    So, I was wondering how a Nessie would appear on sonar which was devoid of filled lungs and no swimbladder? Probably not visible or barely visible?

    Also, important to note the scenario of a largely quiescent bottom dweller. Less food = less activity.

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    1. Hi GB! Well I am not an expert on sonar by any means, but my take on it from things I've run across is that large, air-filled lungs would light up like a Christmas tree on sonar. Even fish show up because of the gas in their swim bladders. Whether a large animal that had vented its lungs before diving would show up would, as I gather it, depend on the density of its body. If it's no denser than the surrounding water, I assume it would be invisible. I've no idea what to expect from the in-between stages.

      I agree that if we have anything, it's a benthic (bottom dwelling) animal that doesn't move until it has to. Which means it's specific gravity must be at least slightly higher than 1 (denser than water) or it would constantly burn calories just fighting the tendency to float upwards.

      A good model might be sharks, and I intend looking into them a good bit more. They lack swim bladders, and are very cartilaginous as are the large aquatic amphibians. I wonder what sonar echoes are returned by Megamouth, Greenland, and Mako sharks respectively? The first two in particular, as they top out at "monster" sizes.

      I should add, unlike aquatic salamanders that absorb all their oxygen through their skin, most sharks have to swim continuously to keep oxygenated water flowing through their gills, making them a bad model in most respects, but perhaps still good for sonar comparisons. This is where amphibians have all the tetrapods that came after them, and many of the fish that came before them, soundly beat: they spend zero calories on the act of respiration. It gives them minute food requirements even compared to reptiles, and the colder the water (meaning more oxygen in it available for dermal respiration) the bigger their edge.



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  3. I would like to say thanks, this is an interesting theory that I find more believable then most. I have several questions for you. Are there any known species of salamander that actually have a tail that sticks out of the water like that when they hunt, or at any other time for that matter? Also, have you noticed a pattern based on time of year that people report neck/tail sightings? If it's a hunting behavior I would expect those sightings to be more common when there are salmon in the loch. Lastly, are there any large salamanders in the fossil record from the area?

    On a side note, I live in Aurora, Colorado and I used to see tiger salamanders all the time in the creeks behind my house. I have not seen any since they started putting up housing developments and expanding the roads 9-10 years ago, which makes me believe you are right that they may stay tadpoles depending on the activity in the area.

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  4. Here is a California newt tail, above water and striking that somewhat classic pose: http://www.flickr.com/photos/kayucian/5527032775/

    It took quite a bit of internet digging to find even that, as photos of surface activity among salamanders are a bit rare, except for mating photos -- tails can be seen in all kinds of strange positions during surface amplexus, but those aren't exactly static poses.

    I haven't viewed the long-neck reports with regards to date, but that might be an informative future undertaking. But as the long-neck reports are actually very scarce at only 15% of the total sightings, it won't be much of a sample size.

    There are indeed gigantic amphibians in Scotland's fossil record, but on an order of hundreds of millions of years old -- nothing recent enough to imply any direct connection. Scotland wasn't even Scotland in those eras. The most recent, truly gigantic fossil salamanders - the last of the Labyrinthodonts - occur in southern Gondwanaland before the KT extinction event, all aquatic species, and ranging up to a fairly enormous 7 meters in length. What was later to become Australia, as it separated and drifted north towards the equator, was much colder at the time, still giving aquatic amphibians a metabolic edge over the aquatic reptiles that had displaced them everywhere else.

    It'll be interesting to see if your tiger salamanders do reappear after construction quiets down -- there could be tadpoles there right now suppressing metamorphosis!

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    1. I don't buy the geologic dating scam.Tesla proved that the radioactive neuclei was a stepping down of higher resonance, frequency vibrations of energy from primary solar rays and starlight.he proved this by stopping the nuclear so called reactions in radium by shielding from the primary solar rays.so the large fossils may be recent.in addition,there are many examples of fossilized items that were created in decades or less.when a whole psyence is created, and egos and mortgages are involved,then the bull will be continued.

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    2. Tesla was a genius in applied science, but in the area of theoretical physics he was at the distinct disadvantage of laboring under pre-atomic era paradigms of the 18th and 19th centuries. He still believed in an all-pervasive Ether, didn't believe electrons existed, didn't believe the atom could be split or that matter and energy were interchangeable. He was highly critical of Einstein's new-fangled Theory of Relativity, calling it "idle speculations and false conceptions, as that of curved space". On all these points, Tesla was proven wrong and Einstein of course has been proven correct time and time again. This doesn't take away from Tesla being a great engineer and a fantastic electrical inventor. Einstein himself started to sound like Tesla when he refused to accept Quantum Mechanics. We are all to some extent a product of our times, and even our greatest minds have traditions they don't want to let go.

      Using Tesla's physics to date fossils is to put one's foot firmly into a pile of mucky brown pseudo-science. None of the giant Labyrinthodont fossils found to date are younger than the mid-Cretaceous. But do notice I only said "found to date" -- more on this in a later article :)

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  5. Excellent article! The part about smooth, vertical submersion especially caught my attention as I have noticed such a feature in multiple "sea serpent" reports (I admittedly haven't done much research into Loch Ness, but I can say that one Lake Champlain report which I have looked at has mentioned such "sinking" as well). I find it quite compelling that such a feature is reported across this broad of a spectrum and feel that it's support for the possibly authenticity of such eyewitness observations.

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  6. Welcome Jay! Good to see you here, and thanks for the compliment.

    These smooth submergence exits are a unifying feature -- and not something witnesses would need to invent. In fact for better fiction, wouldn't a great whirl and splash make for better drama, at least more of the time?

    I have strong doubts that every unrecognized aquatic animal in the world belongs to the same taxon. It's the taxon or class these animals in common DO NOT belong to that may be significant. We have large amphibians and/or aquatic reptiles adjusting their specific gravity by means of lungs, perhaps vestigial lungs in some cases. These are animals without swim bladders, ruling out all of the ray finned fish. That leaves us with animals that don't fit in well with the classified species.

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