Yep, rattlers can swim. Reminds me of a true story.
When I first moved to Florida back in '72, I got a job with a large land developer. They were developing the city I live in. I had some accounting experience, I was young enough (32) to be foolish, and I jumped at the job they offered. They were building roads, Florida style, and they needed someone to act as a "spy" for the Miami headquarters to make sure that costs stayed in line.
My job was to spend half of my time in the field, watching the roads being built (over 700 miles of them, at the time), and keeping accurate notes of the conditions I saw. I carried maps on which I noted the conditions for each segment of road -- sandy, hardpan, muck, wet, dry, high, low, heavily vegetated, clear, etc. I watched and noted as they cleared, surveyed, graded, laid down the soil cement base, paved and seeded the swales. Then, I spent the other half of my time in the office. There was about a month's delay as the reports were generated and sent to me ragarding the actual amount of money spent on each phase of each segment. I compared my maps and notes with the actual costs incurred, and wrote reports to headquarters about whether the costs were justified by the conditions. It was interesting and fascinating, and I learned a lot about Florida, how roads are built, etc.
The supervisor of road construction, Julius, knew exactly what I was doing, of course, and he supported me completely. He was one of the old school of honorable craftsmen, he knew his job extrememly well, and he had nothing to hide from the bean counters down in Miami. He welcomed my presence and helped me "spy" on him.
The only problem was that Julius was an Old-Boy country redneck with a backwoods sense of humor, and I was an earnest, young, bearded weirdo fresh from Yankee-land. Julius got to pull out all of his old jokes. One day, when I was riding with him to see the new construction areas, he commenced to tell me that rattlesnakes always travel from East to West in that part of Florida. He told me to keep my eyes open for snakes crossing the roads, or the cleared areas, or the river, and I would see that they were always going from East to West, never the other way. We saw lots of them, because our construction was tearing up their habitat. Julius carried a revolver in the glove box of his Blazer, and when he spotted one, he'd say, "Hand me that pistol there, Boy," and he'd roll down the window and shoot them. Rarely needed more than one shot. He never let me shoot one; he always said, "I ain't gonna let some damn fool Yankee kid shoot me by mistake when he oughter be aimin' at the dangblasted snake."
The first thing I doubted was that they could swim the river. Sure enough, however, I kept my eyes open, and I saw them swimming across. The St. Lucie RIver is a pretty good size at our location, probably 150' to 200' across. The snakes I saw were swimming like the Loch Ness monster, with humps sticking out of the water, and their heads sticking up.
The next weird thing was, even though I knew Julius was pulling my leg, I never saw a rattlesnake going any direction except East to West. Maybe they travel the other way at night; I don't know. But, just like he said, they always followed the sun. Maybe they all came out of the Atlantic Ocean, traveled to the Gulf of Mexico and died there. Of course, this was back in the days when there weren't very many people here, yet. I haven't seen a rattlesnake in the city for over 20 years.
The company had offered me a truck, but I turned them down and took mileage, instead. Most of the time, I rode a 185cc Suzuki dirt bike with the clipboard of maps bungi-corded to the gas tank. I could scoot around the back woods and navigate the sugar sand better and faster than a 4-wheel drive, and I made a profit on the mileage they paid. Pretty soon, I had a reputation among all the heavy equipment operators as the "kid who hates snakes". They would tell each stories that went something like, "I was running my dozer, and here come this motor sickle down the path with no one on it. I looked back about a hundred yards, and there was a snake. So, I looked up in the sky about a hundred yards, and there was the kid."
What got to me the most was pygmy rattlers:
The doggone things are only about 15" long. They aren't usually deadly, but they can sure make you sick. One day as I was about to dive in our pool, I spotted one swimming along the edge. From that day on, I looked
real careful into the pool before I got in it.
Anyway, check out the rattlers in your area. According to Julius, they're always going to be traveling from East to West.