A 15-year old girl and her family came to enjoy the creek in the sweltering Florida heat.
The alligators came, as they have done for millions of years, to breed.
One gator in particular - a nine-foot specimen - cut a path toward the girl floating on a raft in the Ocala National Forest in central Florida on Friday afternoon.
She thought fast, scurrying up a tree branch hanging over the water. The alligator hissed and waited at the base of the tree.
"My daughter is stuck in a fricking tree and there are gators surrounding her. We can't get her out. She's just 15," Jordan Broderick's mother told a dispatcher in a frantic 911 call.
"Oh my God. Please hurry! Please hurry!" the mother pleaded near Astor, about 55 miles north of Orlando, on the recording provided to The Washington Post by the Lake County Sheriff's Office.
Jordan, her mother and the dispatcher may not have known what the alligators are coded with instinct to know. July marks the tail end of mating season, when the reptiles are particularly aggressive and territorial, sheriff's office spokesman Fred Jones told The Post on Tuesday.
The call, punctuated by f-bombs and drops in cell coverage, highlights the tense minutes Jordan was trapped in the tree, desperately clinging to the limb.
A marine unit was about 20 minutes away, the dispatcher told the mother, whose name was redacted from the incident report, the AP reported.
"Oh my god! My daughter is going to be - dead!" Jordan's mother shouted on the call, using an expletive.
By the time Lake County Sheriff's Deputy Mitch Blackmon arrived, ahead of the marine unit, Jordan had been in the tree for about 30 minutes. She was screaming and exhausted from hanging on, according to the incident report provided to The Post.
The alligator was in the water about four feet from Blackmon, and three feet from the base of the tree, he wrote.
Nature has made American alligators nearly perfect predators. The species hasn't needed to evolve in any substantial way for 8 million years, according to research from the University of Florida.
But genetic progress did not account for AR-15-style semiautomatic rifles.
Blackmon was carrying one, and when he arrived, the alligator hissed, unfazed by his presence. He shouldered the rifle. The alligator turned toward him.
"I fired one single 223 round from my Bushmaster AR15 killing the alligator," Blackmon wrote, noting the .223 calibre of the rifle ammunition. Jordan was helped down, and no person suffered injuries, the report said.
Jordan's mother was not named in the report. Her father, Michael Henderson, was also there. He declined to comment Tuesday.
As for the alligator, it slipped under the water after it was shot. Jones said alligators typically thrash violently when wounded by gunfire, but this one submerged quietly. It was found later Friday night, he said, dead, with a bullet wound to the head.
Jones did not know the sex of the alligator, though researchers at the University of Georgia note that females are known to be fiercely territorial until about mid-July to protect hatchlings.
Baby alligators that lose their mother are typically left defenceless against predators, the researchers found.