MASSA MARITTIMA, ITALY -- The crocodile is either 3 or nearly 7 feet long, is dark brown or greenish, eats fish and frogs in the lake or fasts for 30 to 40 days on end, lives deep in the bottom mud or hides in tall reeds and is growing lonesome in this little vacation town where a lot of people are not so sure he exists at all. Massa Marittima, a picture postcard hill town in southern Tuscany with a population of 9,100, is not the kind of place where people easily get started on stories of things in lakes. After all, this is not the kind of place where there is early darkness or swirling mists that can turn a protruding rock into a crocodile at dusk. But it is a place that will seize upon any eccentricity or slice of fantasy if one should come along.

The problem in Massa Marittima is that the man who first spied the crocodile in Lago dell'Accesa, outside town, was a vacationing German obstetrician, Dr. Dieter Jag -- whose nationality is normally a symbol among Italians of rationality and reliability. Not only did he see the crocodile, but he also described it to Capt. John Napolitano, commander of the local Carabinieri, with enough clinical detail and accuracy to alarm the Carabinieri and the city fathers.

Napolitano, whose father emigrated -- temporarily -- to the United States and named his son John out of attachment to the country he almost adopted, admires American accuracy. So he took careful notes when Jag described how, on the morning of Aug. 10, he watched an Italian couple carry the crocodile to the lake shore, where it slithered into the greenish waters. The couple left in a car with Milan license plates. Jag has since returned to Munich, but his testimony remains a matter of official record and the stuff of newspaper reports.

Is there?  
In no time, speculation about the nature of the animal -- was it a crocodile, or perhaps an alligator, or a caiman? -- and its size, color and relative fierceness eclipsed even discussions of the weekend soccer scores. Mayor Luca Sani, owner of the hotel Il Girafalco and thus a man as interested in tourism as anyone, declared the lake off-limits to tourists, mainly Germans who swim there, and convened a summit meeting of the Carabinieri, the fire brigade, the civil defense corps and the forest rangers to devise a plan to capture the creature. Other townspeople found the story not only hard to believe but also less than amusing.

"Is there this crocodile or isn't there?" asked Giacomo Venaglia, 68, a retired miner who rides his bike to the lake almost daily. When Gianluca Guidi, whose job as a member of the local civil defense unit is to protect curious sightseers by keeping them from the water's edge, replied, "It seems there is," Venaglia snapped, on behalf of all the town's skeptics, "When I went to school we were taught never to write, 'It seems,' but to say, 'Yes, there is,' or 'No, there isn't.' "

Franco Tognarini, who owns a restaurant on a rise above the lake and says he has lost 75 percent of his business since the lake was closed to swimmers, takes the doubt with reasonable good humor. "The provincial quaestor and the fire chief were out in a boat recently, about 1 a.m., when they saw it," he said. "The quaestor shouted, 'Mamma mia, but it's big! Let's get out of here!' It was 2 meters long," or 6½ feet. "It passed under the boat and disappeared," Tognarini continued. "It wasn't a fish. It wasn't a beaver. What else could it have been?" Now, he says, they should go in, capture the animal and bring business back to normal.

As Italians have fewer and fewer children, pets, including exotic animals, have become increasingly popular. But when people go off for their monthlong August vacations, they often abandon them by dropping them by the roadside, or near a lake. Thus pythons are occasionally reported in urinals. Last year a panther set free near Rome that had wandered the city's outskirts for two years was captured unhurt. But the crocodile story shows that for all those who fear for the safety of some unwitting swimmer, there are plenty who are enjoying the visit of the unlikely reptile.

After initial skepticism, Venaglia suggested that it might even have something to do with the legend of the lake. In the Middle Ages, he said, local farmers celebrated no feast day more religiously than July 26, St. Ann's Day. There was no lake then, and farmers who worked the fields where it now lies ignored the celebration. "One day a holy man, passing by, scolded the farmers," Venaglia said, "but they only replied, 'There's work to be done, grain to be harvested,' and whipped their horses and labored on. But as the holy man departed, the earth opened and swallowed the farm, and in its place the lake appeared. Some nights, they say, you can hear the whips and the horses' neighing."

Napolitano tends, soberly, toward the abandoned-pet theory. Just the other day, reports reached him of another abandoned panther, this time in Tuscany. "Fortunately it's in the Piombino area," he said, struggling to control his exasperation. "We only have this pseudo-crocodile."