As you probably know, coral snakes are POISONOUS. They live in warmer places such as the southern U.S. Their favorite habitats are pine and scrub oak sandhills, or maybe hardwood areas that get flooded every year. Some types of coral snakes even spend almost all their time in slow-moving water where there are lots of plants.
The venom of a coral snake is very toxic, and it can kill a person if the person does not get treated. Luckily, since the snakes like to hang out under ground or in leaf debris or other such places, people don't meet up with them very often. Coral snakes are not aggressive, and they will only bite if they are cornered or handled.
A coral snake bite isn't very painful, and it might not seem like a big deal at first. But within a few hours, symptoms such as slurred speech, double vision, and muscle paralysis begin. Eventually, the victim will die of respiratory or heart failure.
Coral snakes are red, yellow, and black in color, which makes them easy to identify. Except that there are some other snakes with the same colors, and these snakes are not poisonous like coral snakes are. These other snakes include the scarlet snake, some kingsnakes, and some milksnakes. To tell these snakes apart from coral snakes people have made up little rhymes like these:
Red on yellow, venom fellow;
red on black, safe from attack.
Red on black, venom lack;
red on yellow, killer fellow.
Or you can just remember that if the yellow touches both the other colors, it's a coral snake.
My own philosophy is that if you see any snake of any size or color, you should just run the other way. That's much easier than trying to stand there and figure out if the snake is poisonous or not!