I just recently became aware of a YouTube video of an alleged sea serpent in the waters off Sanibel Island. The people who saw the creature described it as having a head which "resembled a sea otter" and a body which "looked like a giant 20 foot plus snake".
Nothing shown in the video remotely looks like what they have described, and to everyone's great misfortune it appears the couple who video-recorded the thing stopped recording after only 54 seconds. In truth, the dark rotund thing whose back appears briefly breaking the water looks to me like a manatee or young whale. Cool, but relatively ordinary. (And for Heaven's sake, people, stop calling it "the Loch Ness Monster". The Loch Ness Monster is in Loch Ness.)
But as Jay Cooney points out, Scott Marlowe's The Cryptid Creatures of Florida tells anecdotes about similar sounding sea serpents with mammalian heads:
"Two navy men stationed at the Jacksonville Naval Air Station reportedly observed a long-necked animal with 'antennae' atop a head similar to that of a dog. Two fishermen reported a similar animal on a separate occasion, reflecting some of the 'cadborosaurus' reports from British Columbia... Alleged Florida 'sea monster' footage taken by Gene Sowerwine caused much excitement when it was revealed on an episode of MonsterQuest in 2007, but it was later found to show a manatee with an injured tail and a wayward bearded seal."
Then, too, let's remember the 1901 report of an Everglades sea monster said to have a head like a cross between a deer and a catfish. But until someone shows me a specimen of something, I'm not buying any of it.