Of Loch Ness, Salamanders, and Buoyancy
Posted by: Steve Plambeck on October 15th, 2013
What could belly-up axolotls (Ambystoma mexicanum) and hungry tiger salamander tadpoles have to tell us about anything strange seen in Loch Ness?
Perhaps quite a bit, actually. It’s all a matter of specific gravity, evolutionary ploys, and how to tool around a large Scottish lake if you’re born without a swim bladder.
My thanks to Christopher Hjelte, a reader of my 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!
Steven G. Plambeck is an amateur researcher, armchair paleoanthropologist, and by dint of a long standing interest in the phenomenon associated with Loch Ness may be called an armchair cryptozoologist as well without taking offense. He is the author of "The Loch Ness Giant Salamander" blogspot, and arguably the current leading proponent of the giant amphibian theory regarding the nature of that possible creature.
The major argument against salamanders in Loch Ness is that salamander eggs and larvae are routinely eaten by fish populations in lakes and other bodies of water. In these environs, salamanders lay their eggs out of the water in protected wet areas or in very shallow water where predacious fish are less common to visit. The larval stages stay close in the shallows for protection from fish and other predators until they are large enough to navigate deeper waters. Masses of large salamander eggs would not be a secret to the locals at Loch Ness. I have kept both axolotls and larval tiger salamanders and they occasionally do come up for a gulp of air…practice for the future I imagine.
The average temperature of the Loch is too cold for the axolotl proper, but I imagine that a large version of salamander could exist in the Loch, but I doubt very much it could exist and be totally unknown to the locals, especially frog and toad collecting young boys. The completely aquatic giant salamanders in North America, Mudpuppies and Hellbenders lead just such a lifestyle but they are hardly unknown the locals. In fact, Hellbenders can be taken on hook and line if your bait is on the bottom. It is not impossible for a giant salamander to dwell in Loch Ness but very unlikely to live there and be unknown the local populace…especially the fisherman.
You are quite right on nearly every point there cryptokellie, although as to egg laying strategies the Chinese and Japanese giant salamanders follow a slightly different strategy (perhaps that third member of their family, the Hellbender does too, but I haven’t run across details of Hellbender reproduction). But the larger two species lay and hide there eggs in underwater dens, which the male then guards with his life until hatching. Although whether the correct overhangs needed for this exist at depth in Loch Ness hasn’t been established. And it would still leave small larva unprotected hatching and leaving the den.
That still leaves a couple bases uncovered though. Viviparous reproduction, which does turn up in a number of amphibian species, and breeding outside the Loch. In the viviparous case, juveniles are smaller versions of the adults rather than pre-morphic larva, and can in some species be quite large relatively speaking (that is, born at a considerable percentage of the final adult size).
Marine breeding has problems enough to warrant it’s own article, but may not be entirely out of the question.
I fully agree though that there aren’t a bunch of tiny, juvenile Nessie’s in the Loch, or they’d occasionally get caught or trapped and we’d have specimens.
The differences with the Giant Salamanders of the family Cryptobranchidae are in the habitats they occupy. The Chinese and Japanese giant salamanders and the North American Hellbender all inhabit relatively shallow, fast moving, sections of rivers and streams, not deep water lakes like Loch Ness. All known viviparous salamanders are terrestrial and water does not play a role in reproduction although dampness does. There are no current marine salamanders or amphibians for that matter. The extrapolation of a Chinese Giant Salamander into a Loch Ness type animal could possibly occur if a number of adaptations evolved for it to so. These would include; diet adaptation to deep water environ. A proportionate increase of skin area to allow for aquatic respiration in a much larger animal. The Chinese Salamander achieves this with deeper skin folds. Adaptation to diurnal activity as the all the Cryptobranchidae are nocturnal. These adaptations are not at all impossible and in fact quite possible. The only drawbacks are that the Loch Ness subject sightings and photographic evidence do not resemble what this animal would have come to look like and certainly some number the 500 to 1000 larvae/young created by each of the breeding pairs would have been seen, netted, or some part of retrieved from the loch after all this time. Predaceous fish would get to some of these offspring at some point and remains would have surely been found.
Not impossible by any means but to be unfamiliar to lakeside residents and the commercial fisherman combing this comparatively small body of water is highly unlikely.
Amphibians are so full of surprises, it’s hard to rule out anything, including an adaptation to viviparous reproduction by an aquatic salamander. In fact when the fossil record is included, amphibians have tried out every form of reproduction known to man (and probably some we never thought of 🙂 Live birth has even been established now for one species of Devonian fish, so mammals were many millions of years late getting to the party.
The living Crypotbranchids practice external fertilization in water, which is assumed to be the primitive state. The more modern branch of salamanders practices a wide variety of methods, with viviparous birth apparently limited to terrestrial newts, although it’s hard to state unequivocally this has always been the case.
But here’s a real kicker: aquatic Caecilians, those “legless salamanders” that are so often mistaken for eels, practice not only internal insemination but viviparous birth, clearly a bit of an advantage for purely aquatic species. Birth is pretty messy:
http://www.youtube.com/watch?v=agdz-m6K66c
Those big external gills (manes, if you like) are discarded almost immediately after birth. There is no further metamorphosis – that was completed before birth. Typhlonectidaes mothers such as in this example birth a very small brood of very large “infants” at one time, each about half as long as the mother! Granted the members of this species are small to start. Less small is the related species A. eiselti, which grow as large if not larger than the Japanese Giant Salamander — but with only 6 live specimens ever caught we don’t know if they reproduce exactly like their smaller relations yet.
If there’s a 25 foot amphibian in Loch Ness giving birth to half a dozen or even fewer 10 foot versions of herself at one time, those juveniles are already larger than anything else native to the loch except for the adults of their own species. Likely? Perhaps not. But something to ponder.