The snake was living near the edge of what herpetologists consider its normal range, but its identity was further solidified by its swimming style. A cottonmouth swims with its entire body flat on the surface.

Once the snake became aware of our presence, I eased the boat toward it very slowly and it moved out of our way. Cottonmouths have a reputation for being aggressive, but their bad attitude is mostly bluff. When cornered, they open their mouths in a threat display, showing the white mouth lining from which their common name is derived.

The open mouth display is the cottonmouth equivalent of a rattlesnake's buzz, but it's basically a warning — not an indication of a bad temper. Once on the bank, I tried to approach the snake with a 300 mm lens on my camera, just to see if I could get the cottonmouth response. Since he was not cornered, the snake merely swam away, in search of a quieter neighborhood.

IN THE KNOW

Rattlesnake facts

Rattlers get their name from specialized scales on the end of their tails that create a dry, buzzing sound when shaken.

Rattlesnakes add a rattle each time they shed their skins — up to three times annually. They may also break off rattles. The number of rattles is not an accurate indication of a snake's age.

Not all rattlers sound a warning.

There are exceptions to every rule but most snakes can strike about one half their body length.

Protect yourself by wearing sturdy boots when walking through heavy cover. Do not reach into an area surrounded by cover.

During the heat of summer, snakes are most active at night.

Not all snakebites result in venom being injected. Some bites, known as dry bites, inject no venom.

If bitten by a rattlesnake or any poisonous snake, seek medical treatment as quickly as possible. It helps if you can positively identify the species of snake that bit you. Only five or six of the 7,000 or so snakebites that occur annually in the U.S. result in fatalities, but snake venom can make you very sick and may result in serious tissue damage. Ninety-five percent of the U.S. snakebite fatalities are from rattlesnake bites.

Distributed by McClatchy-Tribune Information Services.