In the past, people have been making a lot of absurd claims as to what was being see in the Northwest coast area and being called "Cadborosaurus (It seems that historically it was called "Old Reliable" in earlier periods)
The original idea was that it was a long noodle that swam above-and-below the surface in "Loops" and several of the reports actually stated that as if it were a fact. This is actually physically impossible for anything with an anatomy more substantial than a swimming pool inflatable float, it would have to have more of the body underwater. Together with this, the traditional image of the Classical-age Hippocampus influenced the ideas about Sea-serpent and "Water Horse" sightings on both the Eastern and Western coasts of North America. Heuvelmans' Merhorse can be taken as basically a transcription of the Hippocampus into an attempted Scientific description.
The "Cadborosaurus" image (Together with its inland analogue, Ogopogo) was a recognition that a significant number of sightings featured hair-covered creatures that had horselike or camel-like heads, obviously ungulate-type heads with large round nostrils at the end of the blunt snout and a distinctly overhanging upper lip. Other frequently-observed features included floppy ears, beards or bells, manes and short horns, actually the beginning growth of antlers. The eyes were placed in a prominent horselike position at the top of the head, with the bony sockets and skull structure indicated. These are moose heads and the resemblance to moose heads is undeniable (Dick Raynor has told me he was the one that initially made the Cadborosaurus-Moose comparison below, but I had got it initially from the Cryptomundo site several years ago)

There is little doubt that this entire series of Water Horse sightings has so polluted the public's ideas about "Cadborosaurus" that these reports are usually factored into any composites which are made. Clearly this is a self-evident mistake and all such reports are to be removed from the bulk of the reports in any attempt to see what the "Real" Cadborosaurus reports are like.
Above is a drawing composite of various "Cadborosaurus" witness' drawings made for comparison and posted by Cameron McCormack on the "Lord Geekington" blog: below is my amended version posted on this blog earlier, indicating which reports I thought were swimming moose and which ones were plausible Long Necked Sea Serpent Reports (With the Naden Harbour corpse, a pipefish and a couple of probable Elephant seals also thrown in there for good measure)
This boils down to a series of Plesiosaur-shaped creature reports
That are mostly comparable to each other and shown in the composite below.Above are the insets showing a slightly elaborated Swimming Moose report and the 1933 Kemp report from the Chatham Islands (One of the defining Plesiosaur-shaped reports) at center and again at right, the inset showing the presumed appearance of "Cadborosaurus willsi" in life. The Plesiosaur-shaped drawings are all headed in the same direction even if they are drawn slightly disproportionate to each other (I am not certain about the largest head shown here but Im leaving it in because its about the right shape we see elsewhere)

Here is a larger view of the Kemp sighting: Head+neck, body, and tail are approximate thirds of the total length each. It is important to note that the "Mane" in such creatures is definitely the forwatd part of the "Row of spines" further down the back. I take it that the crest is fleshy and not actually composed of either spines or hairs: it is commonly called a "Fin". I believe the fleshy growth comes out in the mating season and is used in mating contests, and that the longer strips of "mane" material on the neck there to be pulled out in ritual combats between the males, providing a nonlethal way for the males to confront each other. The mane is possibly shed or absorbed off-season. Maned individuals are larger (by perhaps another quarter in the length) and have richer coloring with more contrast between the lighter and darker sections of the skin. Like Costello, I support the notion that some males have a ring around the eye, making the eye appear lighter. The females are a duller grey, grey-brown or brown, but the males are a brighter reddish brown or (less commonly) greenish or olive colour" the mane and/or spines on the back are the same colour as the rest of the back. In the off-season (winter) it does seem that male "Cadborosaurus" have a more muted coloration and in general tend to resemble the females more, although they still remain larger. Swimming moose have much the same appearance year-round except when males have the full growth of antlers, and some of the inland Water Horse/Swimming moose reports DO include the moose antlers.
Some of the sightings mention the "Mane" seems to move as if it was all piece and one continuous length like a fin, and the most common comparison is that it looks like seaweed (usually kelp)
All in all the Plesiosaur-shaped creature reports are in good agreement with the composites made by Oudemans, Dinsdale, Sanderson and myself (each independently) especially in the head and neck (Once again it is confirmed that Oudemans allowed too much length for the tail, although some "Cadborosaurs" do seem to have much longer tails than others) The "Cadborosaurus" reconstruction is completely inadequate to account for a very long neck, a very bulky body or a very small head in combination with either a very long neck or a very bulky body.
NOTE: in his criticism of my identification of some of these reports as swimming moose, Jay Cooney said that moose do not occur in the Vancouver area. In this he was wrong because my range-maps show that it DOES occur in that area, one of the few parts of British Columbia where the moose range goes down to the coast, and they could very easily be seen swimming in the Georgia Straits adjoining, and around the various smaller islands along that coastline.
Please see the earlier discussions on "Cadborosaurus" on this blog:
http://frontiersofzoology.blogspot.com/2012/04/some-more-notes-on-cadborosaurus.html
http://frontiersofzoology.blogspot.com/2012/08/some-more-notes-on-cadborosaurus-2.html
The following information is from George Eberhart,
Mysterious Creatures, 2002:
Caddy
Sea Monster of t he coast of British Columbia,
Canada.
Etymology: Name popularized if not coined
October 11, 1933, by Victoria (B.C.) Daily Times
edit or Archie H. Wills after repeated sightings in
Cadboro Bay, British Columbia. Short form of
Cadborosaurus, coined at the same time.
Variant names: Amy, Cadborosaurus, Edizgiganteus (after Ediz Hook Light , Washington),
Haietluk, Klamahsosaurus (on Texada Island),
Penda (after Pender Island).
Scientific name: Cadborosaurus willsi, proposed
by Edwar d L. Bousfield and Paul H.
LeBlond in 1995.
Physical description: Serpentine body that
forms many humps or loops. Length, 16–100
feet . Diameter , 2 feet 6 inches–8 feet . Light
brown to black. Small head resembles a sheep,
horse, giraffe, or camel. Eyes in the front of the
head. Small ears or horns. Pointed tongue. Two
rows of fishlike teeth. Mane or fur sometimes reported. Neck is 3–12 feet long, about as thick as
an arm. One pair of front flippers. Back sometimes appear s serrated, sometimes smooth. Flat
tail is snake-like, fluked or formed from fused back flippers.
Behavior: Does not appear to undulate when
it swims. Fast swimming speed, clocked at 40
knot s. Breathes in short pants. Makes whalelike
grunt s and hisses. Feeds on herring, salmon, and
ducks.
Distribution: British Columbia seacoast , especially
around Cadboro Bay and the Strait of
Georgia.
Significant sightings: A crew member of t he
ship Columbia under American fur trader Capt .
Robert Gray was the first to report a Caddy
sighting in 1791.
Osmond Fergusson watched a 25-foot animal
wit h a long neck near t he Queen Charlotte Islands,
British Columbia, on June 26, 1897.
In September 1905 or 1906, Philip H. Welch
saw a brown animal with a 6- to 8-foot neck
from a distance of 100 yards away in Johnstone
Strait . It had two bumps on its head that were 5
inches high and rounded on top.
F. W. Kemp and his wife and son watched an
80-foot maned animal while they were sitting
on the Chatham Island beach, British Columbia,
on August 10, 1932.
On Sept ember 23, 1933, Dorothea Hooper
and a neighbor observed a serpentine animal
with a serrated back cavorting in Cadboro Bay
about 400 yards distant. It created a commotion
in the water as it swam out to sea.
Maj. W. H. Langley and his wife were sailing
in Haro Strait on October 1, 1933, when they
heard a loud grunt off Chatham Island. They
saw the back of a huge, dark-green creature with
serrated markings on the top and sides.
Charles F. Eagles sketched a 60-foot animal
that he saw in Oak Bay on October 14, 1933. It
had crocodile-like spines on it s neck.
On December 3, 1933, Justice of the Peace
G. F. Parkyn of Bedwell Harbour was one of
twelve people watching from Pender Island as
an animal with a large, horselike head and neck
gulped down a duck that had just been shot by
Cyril Andrews.
In 1936, E. J. Stephenson and his wife and
son watched a yellow-and-bluish, 90-foot -long,
3-foot -thick animal crawling over a reef into a
lagoon on Saturna Island.
A 10- t o 12-foot carcass of apparently a
young Caddy was removed from the stomach of
a sperm whale, photographed, and displayed for
a while at Naden Harbour whaling station in
1937. The photo shows it stretched out on
packing cases. It was about 10 feet long, wit h a
camel-like head, traces of flippers, and a paddling
tail. The carcass was allegedly shipped off
to t he Field Museum in Chicago, but there is no
record of it s arrival.
A Canadian naval officer was fishing in an
open boat off Esquimalt Harbour in November
1950 when a 30-foot Caddy appeared and created a heavy wash. It swam with an undulating
motion using large flipper s on either side. It
snapped its teeth together once before it dived
after twenty-five seconds.
On Februar y 12, 1953, R. D. Cockburn, C.
P. Crawford, and Ron Loach saw an animal
with three humps off Qualicum Beach for five
minutes. Two other men got into a boat and
rowed within 20 feet , but it submerged and
reappeared 100 yards away. It s head was dogshaped
and had two horns.
In late November 1959, David Miller and Alfred Webb came within 30 feet of an animal
with a 10-foot neck sticking straight up out of
the water off Discovery Island. It had coarse
brown fur , red eyes, and small ears.[The closeness to the creature and its size seem to be exaggerated, since this otherwise sounds very much like another swimming moose report, including the ears]
A 16-inch-long juvenile Caddy was caught in
a net by William Hagelund in 1968 off De
Courcy Island, but it was thrown back. It had
spiny teeth, a saw-toothed ridge of plates along
its backbone, and a bilobate tail. A soft , yellow
fuzz covered it s under sides.[this is almost certainly a fish]
Mechanical engineer Jim M. Thompson was
fishing off Spanish Banks, Vancouver , in January 1984 when an 18- to 22-foot serpentine animal
surfaced about 100 feet away. It had a giraffelike
head with small stubby horns and
floppy ears.
In May 1992, music professor John Celona
saw a multihumped animal about 25 feet long
while sailing.
Student s Damian Grant and Ryan Green
were swimming across Telegraph Bay in May
1994 when they saw a 20-foot animal with two
humps.
Possible explanations:
(1) The Nor thern sea lion (Eumetopias
jubatus) can appear serpentine in the water
but only grows to about 10 feet 6 inches
long.
(2) The Northern elephant seal (Mirounga
angustirostris) is found in British Columbian
waters in the nonbreeding season, but it
only measures up to [20] feet long and does
not have an elongated neck.
(3) A surviving basilosaurid type of archaic
whale, suggested by Roy Mackal and Karl
Shuker . Some basilosaur ids were serpentine,
grew up t o 80 feet long, and lived in the
Late Eocene, about 42 million years ago.
They had a tail fluke, but it’s unknown
whether it was used primarily for propulsion
or steering. They are mainly known from
t he eastern United States and Egypt but
may have been worldwide in distribution.
(4) An evolved plesiosaur , suggested by
Edward Bousfield and Paul LeBlond. This
gr oup of long-necked marine reptiles swam
with paddlelike limbs and had a body
length that varied from 6 t o 46 feet .
Plesiosaur fossils are found continuously
from t he Middle Triassic, 238 million year s
ago, to the Late Cretaceous, 65 million
years ago.[With some fossils reported as PostCretaceous]
(5) A decaying Basking shark (Cetorhinus
maximus) might account for the 1937
Naden Harbour carcass. These sharks take
on a remarkably plesiosaur -like appearance
due to the differential decomposit ion r at es
of t heir gill slit s and lower t ail fluke. A 30-
foot carcass found in November 1934 by
Hugo Sandstrom on Henry Island t urned
out t o be a Basking shark.
(6) Some kind of decapod (crayfish or
lobster ) has been suggested by Aaron Bauer
and Anthony Russell as an explanation for
Hagelund’s juvenile Caddy capture in 1968.
Sources: “Yacht smen Tell of Huge Sea
Ser pent off Vict or ia,” Victoria (B.C.) Daily
Times, Oct ober 5, 1933, p. 1; “The Loch Ness
Monst er Paralleled in Canada,” Illustrated
London News 184 (Januar y 6, 1934): 8; “A
Canadian ‘Monst er ,’” Illustrated London News
185 (December 15, 1934): 1011; Ray Gar dner ,
“Caddy, King of t he Coast ,” Maclean’s
Magazine 63 (June 15, 1950): 24, 42–43; D.
Mat t ison, “An 1897 Sea Ser pent Sight ing in
t he Queen Char lot t e Islands,” B.C. Historical
News 17, no. 2 (1964): 15; Paul H. LeBlond
and John Siber t , Observations of Large
Unidentified Marine Animals in British
Columbia and Adjacent Waters (Vancouver ,
Canada: Univer sit y of Br it ish Columbia,
Inst it ut e of Oceanogr aphy, June 1973);
William A. Hagelund, Whalers No More: A
History of Whaling on the West Coast (Madeir a
Par k, B.C., Canada: Har bour , 1987); Fr eder ic
C. Howay, ed., Voyages of the “Columbia” to the
Northwest Coast, 1787–1790 and 1790–1793
(Por t land: Or egon Hist or ical Societ y, 1990), p.
249; Penny Par k, “Beast fr om t he Deep Puzzles
Zoologist s,” New Scientist 137 (Januar y 23,
1993): 16; Jessica Maxwell, “Seeing Ser pent s,”
Pacific Northwest 27 (Apr il 1993): 30–34; Mike
Dash, “The Dr agons of Vancouver ,” Fortean
Times, no. 70 (August -Sept ember 1993):
46–48; Edwar d L. Bousfield and Paul H.
LeBlond, “An Account of Cadborosaurus willsi,
New Genus, New Species, a Lar ge Aquat ic
Rept ile fr om t he Pacific Coast of Nor t h
Amer ica,” Amphipacifica 1, suppl. 1 (1995):
3–25; Paul H. LeBlond and Edwar d L.
Bousfield, Cadborosaurus: Survivor from the
Deep (Vict or ia, B.C., Canada: Hor sdal and
Schubar t , 1995); Aar on M. Bauer and Ant hony
P. Russell, “A Living Plesiosaur ? A Cr it ical
Assessment of t he Descr ipt ion of Cadborosaurus
willsi,” Cryptozoology 12 (1996): 1–18; Dar r en
Naish, “Anot her Caddy Car cass?” Cryptozoology
Review 2, no. 1 (Summer 1997): 26–29; Paul
H. LeBlond, “Caddy: An Updat e,” Crypto
Dracontology Special, no. 1 (November 2001):
55–59.
Merhorse
A category of Sea Monster identified by
Bernard Heuvelmans.
Scientific name: Halshippus olaimagni, given
by Heuvelmans in 1965.
Variant names: Hippokampos, Maner.
Physical description: Elongated, with smooth,
shiny skin. Length, 15–100 feet, though rarely
exceeding 60 feet. Dark-brown or steel-gray to
black in northern regions; mahogany in warmer
regions. Skin is smooth and shiny, possibly with
short fur. Wide, flat, diamond-shaped head [from in front], described
as similar to that of a horse, camel,
snake, or dog. Head, 3 feet long. Wide mouth,
perhaps edged with light-colored lips. Has
whiskery bristles like a mustache. Enormous,
forward-pointing, black eyes. Slender neck, 10
feet long or more. Often, a long, flowing, reddish[?]
mane hangs down its neck. Jagged crest on
the back. Pair of frontal flippers. Possibly a hind
pair of flippers that form a false tail; alternatively,
a fanlike tail[, flattened flail-like or snakelike tail.]
Behavior: Swims with pronounced vertical
undulations. Rapid speed. Hisses. Feeds on
fishes and possibly giant squid.[The large gap in prey size between small fishes and giant squids makes this unlikely]
Habitat: Semiabyssal depths of 50–100 fathoms
in the daytime, coming to the surface at
night. Frequents coastal areas in temperate regions
and moves further out on the continental
shelf in warmer zones.
Distribution: Nearly cosmopolitan, except for
polar seas and the Indian Ocean. At various
times, it has been seen regularly off New England
and Nova Scotia, the British Isles, Norway
(especially Møre og Romsdal and Trøndelag
Counties), British Columbia and
southeastern Alaska, Portugal and the Canary
Islands, southern California, La Plata in Argentina,
the coast of South Africa, and in the
Coral Sea.
Significant sightings: A description of this type
of animal was first published in 1554 by the
Scandinavian archbishop Olaus Magnus, who
wrote that it was frequently seen in the fjords
around Bergen, Norway. He mentioned the visible
mane, large eyes, and elevated head and
neck as prominent features.
In the spring of 1835, Captain Shibbles of the
brig Mangehan reported an animal with large
eyes and a long, maned neck 10 miles off
Provincetown, Massachusetts.
In the summer of 1846, James Wilson and
James Boehner were in a schooner near the
western shore of St. Margaret’s Bay, Nova Scotia,
Canada, when they saw a 70-foot animal
with a barrel-sized head and a mane. George
Dauphiney spotted a similar animal near Hackett’s
Cove about the same time.
Officers and passengers of the British mailpacket
Athenian observed a 100-foot, darkbrown
sea serpent between the Canary and
Cape Verde Islands in the North Atlantic on
May 6, 1863. Its head and tail were out of the
water, and it had something like a mane or seaweed
on its head.
A “sea-giraffe” was observed by the crew of
the steamer Corinthian east of Newfoundland,
Canada, on August 30, 1913. It first appeared as
a large head with finlike ears and huge blue eyes,
followed by a 20-foot neck. It appeared attached
to a large, seal-like body with four fins colored
light brownish-yellow with darker spots.
Sports fisherman Ralph Bandini saw a maned [or finned]
animal about a mile west of Mosquito Harbor
on San Clemente Island, California, in September
1920. Its neck was 5–6 feet thick, and the
eyes were 12 inches in diameter.[The much larger dimensions suggest this is not the same]
Around 1938, some 100 yards off the coast of
Skeffling, East Riding of Yorkshire, England,
Joan Borgeest watched a huge, green creature
with a flat head, protruding eyes, and a long
mouth that opened and closed. When she called
out to other people in the area, it dived and did
not reappear.
George W. Saggers watched a head and neck
with huge black eyes off Ucluelet, Vancouver Island,
British Columbia, Canada, in November
1947. Its dark-brown mane looked like a bundle
of warts.
Possible explanation: An elongated Seal (Suborder
Pinnipedia) adapted for a semiabyssal marine
existence.
Sources: Olaus Magnus, A Compendious History of the Goths, Swedes and Vandals [1554]
(London: J. Streater, 1658), pp. 225, 227, 231;
“A Sea Serpent,” American Journal of Science 28
(1835): 372–373; “The Great Sea-Serpent,”
Zoologist 21 (1863): 8727; John Ambrose,
“Some Account of the Petrel—the Sea-
Serpent—and the Albicore as Observed at St.
Margaret’s Bay,” Transactions of the Nova Scotia
Institute of Natural Science 1 (1864): 37–40;
“Sea Monster’s Bonny Blue Eyes,” Daily Sketch
(London), September 25, 1913, p. 6; Ralph
Bandini, “I Saw a Sea Monster,” Esquire 2
(June 1934): 90–92; George W. Saggers, “Sea
Serpent off Vancouver,” Fate 1 (Summer
1948): 124–125; Bernard Heuvelmans, In the
Wake of the Sea-Serpents (New York: Hill and
Wang, 1968), pp. 459, 552–557, 566.
[Note: Heuvelmans did NOT think the mane and whiskers of this type were hairs but suggested they were cutaneous fibers of some sort.]