Is it very unlikely that the so-called “Lake Champlain Monsters” are relict Tanystropheid archosauromorph reptiles? Why, yes it is! For many good and sound reasons. As many criticisms that may be leveled at the relict plesiosaur theory for the identity of “Champs”, contrasting the plesiosaur theory with the tanystropheid theory serves as a useful tool to demonstrate the inadequacies of the latter theory. Lake Champlain is a very deep lake, but it is not the Marianas Trench. Compared to the average depths of the Great Lakes, it is a mudhole.

This diagram below represents the deepest portion of Lake Champlain, 400 feet deep at Thompson’s Point near Charlotte, Vt. I have taken a diagram meant to represent a depth of 40 feet and multiplied it ten times.

Compared to the size of the human figures, the depth is impressive. But the average depth of Lake Champlain is 64 feet, though there are many places in excess of 200 feet.

And it’s not like no one is going down there. There are many historic shipwrecks that are dived upon, in times of good weather (http://www.lcmm.org/shipwrecks_history/uhp/uhp.htm ).

IF there are any unknown animals of unusual type masquerading as the Lake Champlain “monsters”, they must be hiding in very deep

water most of the time to be as elusive as they are assumed to be. This would require an animal that is a very good swimmer, adapted for a pelagic or benthic existence, probably with fins or flippers. An animal as big as most of the alleged “monster” reports seem to suggest would have had its origin in the sea, most likely. Which finally brings us back to the Tanystropheus. The two most current interpretations of the lifestyles of the large Tanystropheus sp. species are: (1) they were poor swimmers that inhabited shallow, near shore waters and probably reproduced on land (egg-laying) or (2) they were shore-dwelling animals that fished from the shore with their long necks. Either way, this sounds like a poor fit for something as elusive as the “Champs” seem to be.

Though the evidence for a heavy tail and hindquarters as described by Silvio Renesto would assist in negative bouyancy (if swimming), it is unlikely that it could have kept the animal sunk very deeply. By contrast, evidence of deep diving by plesiosaurs is demonstrated by the presence by avascular necrosis of the limb bones due to decompression syndrome.

The waters of Lake Champlain are very cold : (http://lcyc.info/cruising/safety ) “Lake Champlain remains cold, or at least cool enough to cause hypothermia, all year round. Therefore, the risk of hypothermia is almost always present. Lake Champlain 5-year (1996-2000) average monthly water temp (degrees F): Apr 38.2, May 47.0, June 59.8, July 67.8, Aug 70.8, Sept 66.2, Oct 55.2, Nov 47.4, Dec 41.0.” All known tanystropheid fossil genera existed during the Triassic period (http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=38195 ), a geologic period characterized by warm climates worldwide, with no ice in the polar regions (http://www.ucmp.berkeley.edu/mesozoic/triassic/triassictect.html ). There exists no evidence for elevated metabolisms or special thermal adaptations to cold for any known tanystropheid, unlike the living leatherback turtle (Dermochelys coracea) or some plesiosaur genera (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0013925 , http://www.researchgate.net/publication/44664417_Regulation_of_body_temperature_by_some_Mesozoic_marine_reptiles ). While some relatively small reptiles and amphibians that inhabit Lake

Champlain deal with these winter temperatures by torpor and hibernation (http://www.wvpd.org/AmphibianGuide.pdf ) , large reptiles that lack the special thermal adaptations found in leatherbacks and some plesiosaurs, such as alligators, cannot function and survive at such temperatures (http://www.jstor.org/discover/10.2307/2425371?sid=21106115715883&uid=4&uid=3739256&uid=2&uid=3739600 ). Tanystropheids, built like crocodilians with long, thin necks, would have almost certainly vulnerable to such cold. Since the tanystropheids that inhabited the Triassic period had no need for cold adaptations (and there is no known evidence for geologically younger forms inhabiting cold climates), any speculation about warm-blooded or cold adapted tanystropheids is whistling in the wind. TO BE CONTINUED……