The story began on July 23, 2008 with an article in a local newspaper, The Independent. Jenna Hewitt, 26, of Montauk, and three friends said they found the creature on July 12 at the Ditch Plains beach, two miles east of the district. The beach is a popular surfing spot at Rheinstein Estate Park owned by the town of East Hampton. Jenna Hewitt was quoted:
Her color photograph of the creature ran in black and white under the headline, "The Hound of Bonacville" (a take-off on the nameBonackers, which refers to the natives of East Hampton, and The Hound of the Baskervilles which is a book in the Sherlock Holmes series by Sir Arthur Conan Doyle). The light-hearted article speculated that the creature might be a turtle or some mutantexperiment from the Plum Island Animal Disease Center before noting that Larry Penny, the East Hampton Natural Resources Director, had concluded it was a raccoon with its upper jaw missing. There were rumors that the carcass had been taken away from the site. A local newspaper quoted an anonymous resident who claimed that the animal was only the size of a cat, and that it had decomposed to a skeleton by the time of the press coverage. She would not identify its location for inspection. Hewitt claimed that "a guy took it and put it in the woods in his backyard", but would not say who or where. Her father denied that his daughter was keeping the body's location a secret.
Hewitt and her friends were interviewed on Plum-TV, a local public-access television show. Alanna Navitski, an employee of Evolutionary Media Group in Los Angeles, California, passed a photo of the creature to Anna Holmes at Jezebel, claiming that a friend's sister saw the monster in Montauk. Holmes then passed it along to fellow Gawker Media website Gawker.com which gave it wide attention on July 29 under the headline "Dead Monster Washes Ashore in Montauk".
Cryptozoologist Loren Coleman at Cryptomundo first coined the name the "Montauk Monster" on July 29, 2008. The moniker was disseminated globally on the Internet in the following days. Photographs were widely circulated via email and weblogs, and the national media picked up on it raising speculation about the creature. The potential urban legend stature of the Montauk Monster was noted by Snopes.
On August 4, 2011 the Montauk Monster was featured on the second episode of the third season of Ancient Aliens, titled "Aliens and Monsters".
Palaeozoologist Darren Naish studied the photograph and concluded from visible dentition and the front paws that the creature was a raccoon, with its odd appearance merely a byproduct of decomposition and water action removing most of the animal's hair and some of its flesh.
Speculation in published reports included theories that the Montauk Monster might have been a turtle without its shell—even though turtles' shells cannot be removed without damaging the spine, and they do not have teeth as appear in the photograph—a dog, or a science experiment from the nearby government animal testing facility, the Plum Island Animal Disease Center. The creature's appearance was believed to have been altered through immersion in water for an extended period before coming to rest on the shore, making it difficult to identify.
William Wise, director of Stony Brook University's Living Marine Resources Institute, interpreted the photo along with a colleague; they deemed the creature a fake, most likely the result of "someone who got very creative with latex", although his "next-best guess" was that the creature could be a diseased dog or coyote which had "been in the sea for a while". Wise discounted the following general possibilities:
- Raccoon – the legs appear to be too long in proportion to the body.
- Sea turtle – sea turtles do not have fur or teeth.
- Rodent – rodents have two huge, curved incisor teeth in front of their mouths.
- Dog or other canine such as a coyote – although the body appears doglike, neither its prominent eye ridge nor its feet are canine.
- Sheep or other ovine – although the feet and face look "somewhat ovine", sheep do not have sharp teeth.
On August 1, Gawker published pictures and X-ray images of a water rat, an Australian rodent with several similarities to the Montauk Monster, such as the beak, tail, feet, and size. On the same day, Jeff Corwin appeared on Fox News and claimed that upon close inspection of the photograph, he feels sure the monster is merely a raccoon or dog that has decomposed slightly.This was backed up by Darren Naish, a British paleontologist, who examined the images and agreed that, if real, the creature was a raccoon. Naish says that "claims that the limb proportions of the Montauk carcass are unlike those of raccoons are not correct", and on his blog he provides an illustration of an intact raccoon corpse drawn over the corpse in the photograph. Furthermore he points out the strong resemblance of the skull profile to that of a raccoon, and the long fingers, which are typical of raccoons, and unlike those of other carnivores, e.g. dogs.
On August 5, 2008, Fox News Channel's Morning Show repeated speculation that the beast is a decayed corpse of a capybara, even though capybaras do not have tails. The next day, the same program reported that an unnamed man claimed that the animal's carcass had been stolen from his front yard.
In a 2009 episode of Monster Quest, cryptozoologist Loren Coleman examined a latex replica of the Montauk Monster's remains and proposed that it was the remains of a raccoon, due to similar body structures and skull shape.
On March 30, 2011, an odd-looking unidentified creature was found in Northville, New York, and the student who discovered it found it to "resemble the Montauk Monster in a lot of ways". In July 2012, a similar-looking creature dubbed the East River Monsterwas found beneath the Brooklyn Bridge, in the East River, New York City. Although the Parks Department identified it as a pig carcass before disposing of it, comparisons were drawn to the Montauk Monster.