...I saw something appear on the surface of the water... [I thought] it would be about 12 feet long and 4 or 5 feet wide.  I did not see either head nor tail but it slowly rose to the surface and stayed in this position some five minutes... afterward on different occasions I have seen it move up and down the river, but I never have, at any time, been able to determine the full length or size of said monster.

After Bateman's report, three other local residents signed affidavits, saying that they had seen a similar monster.  The three included Mrs. Bateman, J.M. Gawf (both of whom did not actually witness the monster, but noted peculiar disturbances in the water), and Z.B. Reid. The following statement is from Reid's affidavit:

...there was a lot of foam and bubbles coming up in a circle about 30 feet in diameter some 300 feet from where we were standing. It did not come up there but appeared about 300 feet upstream. It looked like a large sturgeon or catfish. It went down in about two minutes...

...the thing stayed on top of the water about five or ten minutes. It was making a terrible blowing noise but never did show its head or tail. It was a terrible-looking thing with dingy gray crusted hide.

After the summer of 1937, reports of the White River monster died down until 1971.  Seven more reports of the monster were recorded that year, the first on June 17.  An anonymous witness said:

It didn't really have scales but from where I was standing it looked as if the thing was peeling all over, but it was a smooth type of skin or flesh.

A few days earlier, Ernest Denks of Newport saw the monster. He said it was long and gray, and had a horn protruding from its head.

The most notable sighting of that summer came on June 28, when Cloyce Warren and two friends were fishing in a boat near the Newport Bridge.  Warren stated:

...This giant form rose to the surface and began moving in the middle of the river away from the boat. It was very long and gray colored... We had taken a little Polaroid Swinger with us to take pictures of the fish we caught. I grabbed the camera and managed to get a picture right before it submerged. It appeared to have a spiny backbone that stretched for 30 or more feet...

Another photo was taken by Gary Addington and Lloyd Hamilton near Jacksonport.  The second photo, unfortunately, was ruined by the Newport Daily Independent when it was misdeveloped.  On July 5, a series of large footprints were found on Towhead Island.   The tracks measured 14 inches long and 8 inches wide, and had three clawed toes.   A spur extended at an angle from the heel.  Two trails were found - one leading out of the water and one leading back in.  In a grassy area was a depression, as if something large had lain there.

In the lengthy discussion of the monster in Searching for Hidden Animals, Roy P. Mackal notes that all accounts of the monster are consistent with each other, except in estimates of the monster's size.  Mackal thinks it safe to assume that the creature's actual length was somewhere between 15 and 20 feet.  The coloration is unanimously described as gray.  Several witnesses commented that it looked to be peeling.   When it makes any sort of sound, the sound is described as a cross between a cow and a horse.

From these descriptions, Mackal draws the conclusion that the White River was home to a stranded Mirounga angustirostris, or northern elephant seal.  As unlikely as this identification sounds at first, it does indeed fit the facts.  These seals reach lengths of up to 22 feet; furthermore, males of the species have "trunks" on their snouts which could account for the "horn" Denks saw.  Elephant seals frequent considerable depths, feeding on cephalopods and fish.  This is a habit Mackal believes can adequately account for the fact that the monster was often seen in the deeper parts of the river and why fishing was sometimes reported as poor in areas frequented by the monster.

Furthermore, male elephant seals, when bellowing, would resemble the sounds of the White River monster, and an elephant seal would leave tracks similar to those found on Towhead Island.  An elephant seal also has coloration similar to the monster, and sloughs off skin and hair between May and July - neatly accounting for the "peeling" skin of the monster, which was seen in June and July.

M. angustirostris has been recorded from Mexico and southern California, and Mackal believes that it is entirely possible that an individual in the Gulf of Mexico could have found its way into the Mississippi and thus into the White River.

The only problem with this theory - which on the surface seems a very plausible one - is that the part of Mexico from which M. angustirostris has been recorded is Baja California.  Thus, an individual would have to cross through the Panama Canal to appear in the White River.

This does not, however, entirely rule out Mackal's elephant seal - one or more specimens of M. angustirostris could have been captured and released in the Gulf of Mexico, and from there could easily have swum up the Mississippi into the White River.