WESTBROOK — When Mary Baumer of Durham learned that the Major League Triathlon she signed up for included a swim in the waters where a 9-foot-long snake had been spotted, she decided to drop out.

Then she consulted several people, including the Westbrook recreation director, about the 500-meter swim in the Presumpscot River on whose banks a snake, nicknamed Wessie, was spotted by Westbrook police early this summer. At 8:30 the night before the triathlon, she changed her mind about the race.

“I was freaked out, but I faced my fears,” Baumer said.

It was a wise decision, it turns out. Baumer was the first female over the finish line, despite the fact that she was competing in the 50-to-54 age category in the event Saturday at Riverbank Park. She even beat out her husband in the event, which includes swimming, running and bicycling.

Baumer was one of about 150 athletes who took the plunge into what may be the home territory of an anaconda. The snake has captured the imagination of people and generated headlines across the nation since June, when police saw a snake swallowing a beaver before slithering into the river alongside Riverbank Park.

There have been several sightings since. A large snakeskin was discovered near the river in August. DNA testing identified the skin as belonging to an 8- to 9-foot juvenile anaconda, which is native to South American tropical rain forests.

The tale of the snake – and possibly the snake itself – has only grown larger since. Wessie even has her own Twitter feed named “Wessie P.Thon” with 1,900 followers.

Before hitting the water Saturday morning, the athletes expressed some gallows humor about what lay ahead and a possible encounter with the anaconda, which is not poisonous but packs a painful bite.

John McCall, 75, of Kingfield and Dauphin Island, Alabama, said he was a little worried at his age about being left behind the pack. “I am going to be the straggler,” he said.

Westbrook Fire Chief Andy Turcotte, who manned the medical tent, said he was fully prepared for all emergencies, including a snake bite.

“I didn’t sign up for that,” said Katie Bishop of Windham, the nurse on hand.

“I am joking,” she added.

Dan Cassidy, the chief executive officer of Major League Triathlon, tried to make the best of Wessie.

Triathlon winners received a 4-foot stuffed anaconda toy. Emcee Mike Plant, a major figure in the triathlon world, cracked Wessie jokes.

“I am reasonably certain the snake has eaten recently,” Plant told the amateur athletes just before they jumped in the river.

T-shirts featuring a grinning snake and swimmer went on sale, with 10 percent of the proceeds going to the Westbrook Community Center.

Cassidy said he would like to come back next year to Westbrook, which stood out from other venues because of the river and walking paths. “The entire city has been so very supportive,” he said.

But in the end, Wessie may have scared some people away. The amateur portion of the event had just under 100 participants, although more had registered, Cassidy said.

Another 32 professional triathletes, including 2016 Rio Olympians Ben Kanute and Sarah True, competed in their own event. There was a mini race for about 15 fledgling triathletes.

Jordan Stebbins of Portland, who was the first amateur over the finish line, said he didn’t spot any snakes but had to swim through a lot of river weeds, which he didn’t like.

“It makes you swim faster,” Stebbins said.