To the thousands upon thousands of seals that populate isolated beaches, and the frenzy of great white sharks that have frightened swimmers, now add another creature of the sea: an oddly graceful, roughly 8-foot-long manatee that has probably arrived from Florida to join the throngs of tourists enjoying the warm waters off Cape Cod.
Since mid-August, wildlife experts have documented at least a half-dozen sightings of the transient manatee they believe slowly swam up the East Coast to feed on local vegetation.
He or she still appears intent on taking in popular spots along the Cape, like any vacationer. The issue it faces is one of time: When the water temperatures drop, its chances of survival do, too.
Bill Pouliot and his son, Brayden, saw the wayward manatee while fishing on Bridge Street in Chatham Sunday. When the buoyant gray object came into view, they couldn’t believe its size.
“It was gi-normous,” said the elder Pouliot, mashing together the words “giant” and “enormous” to best describe the girth of the unexpected guest.
At first, both father and son thought the rotund animal spotted foraging on sea grass was a seal that wandered off from its beachy haunts.
But as they further examined the marine creature lazily floating nearby, they concluded it was something else entirely.
“It was just sort of going down to the bottom to eat, and then coming back up, perhaps sunbathing,” Pouliot said.
A second person also reportedly witnessed the manatee in Chatham this week. A picture taken Friday of the animal, its puffy body breaching the murky waters of Oyster Pond, was shared on a Facebook page called “My Fishing Cape Cod.”
Brian Sharp, manager of the International Fund for Animal Welfare marine mammal rescue and research program, said members of the organization headed to Chatham over the weekend to keep tabs on the bulbous animal, as it continued to roam parts of Nantucket Sound.
The animal has moved around quite a bit since the first confirmed sighting was recorded at Dowses Beach, in Osterville, on Aug. 19, Sharp said. There had also been unconfirmed sightings — reports that came in without photographic or video evidence — earlier in the month near the island of Nantucket.
“It’s very mobile,” Sharp said in a telephone interview. “They can travel quite well.”
Since news first reached their desks of the manatee’s arrival, IFAW has been in close contact with officials from the US Fish and Wildlife Service in Florida, which keeps a database of manatees, to see if this particular animal has been identified in the past. So far, federal officials have been unable to match pictures provided by beachgoers on Cape Cod to information previously recorded during their research.
Experts say they aren’t concerned about the manatee’s presence for the time being, as it has shown no immediate signs of trauma or distress. In fact, the water beast has seemed content in its temporary habitat, as it has delighted the public with its appearances.
But keeping an eye on the sea animal, with the help of the public, remains a top priority.
“When we start to get into the cooler weather, which is not that far away for you folks. . . that’s where we begin getting really concerned,” said Chuck Underwood, public information officer for the US Fish and Wildlife Service’s Jacksonville office, which takes the lead in the event of a manatee recovery operation.
Manatees, which are protected under both the Endangered Species and Marine Mammal Protection Acts, can’t survive long in waters that dip below 68 degrees. If the currently unnamed Cape Cod manatee fails to continue its path south, it could die from what is known as “cold stress.”
Such was the case in 2008, when a manatee dubbed Dennis died as a result of his extended stay in Cape Cod’s cooler waters, according to Globe archives.
“These guys really shut down very rapidly,” said New England Aquarium spokesman Tony LaCasse in a statement.
Although the arrival of a manatee off Cape Cod is slightly “unusual,” officials said, it’s not entirely unheard of.
A. Quinton White, Jr., executive director of the Marine Science Research Institute at Jacksonville University, said manatees have been known, on occasion, to travel as far north as Massachusetts.
Whether it’s due to warming waters as a result of climate change remains unclear. But an increase in the animals’ numbers may play a role.
Earlier this year, federal officials proposed reclassifying the species’ status from “endangered” to “threatened,” citing “improvements in its population and habitat conditions.”
In 2009, a year after the death of Dennis, another gentle giant visited the region. Ilya, a 1,100-pound sea cow, spent the latter part of the summer that year in Cape Cod, before he was later spotted in New Jersey in October, and given a lift back to Florida in a US Coast Guard cargo plane.
Underwood, of the federal fish and wildlife agency, hopes that the state’s most recent ocean guest won’t require the assistance of a rescue mission to make it back home, however.
“If it moves, hopefully the next time we get a sighting it moves south,” he said. “If it moves north, we will want to keep a close eye on any reports.”
Underwood and others are concerned about boat operators interacting with — or worse, their vessels coming into contact with — the manatee.
As more people flock to the Cape to bid farewell to the season, experts are urging the public to remain alert, and give the unhurried drifter some room to roam.
“Enjoy it, report it — but do so from afar,” Underwood said. “We prefer they keep a distance and leave the animal alone.”