Quite a few people would have you believe there are only a handful of animals in the wild that are actually dangerous. Truth is that there is a large number of animals that can be dangerous, and many more that can make the camping experience less than enjoyable. Most of these animals can be dealt with though, by using a bit of common sense.
Bears
One of the first animals a person may think of as a problem creature is a bear. However, bears are relatively intelligent animals. They are the largest natural predator in North America, but they are also scavengers. Despite their bulk, they are also surprisingly fast. Over a short distance, a black bear can outrun a horse. They are also great at climbing trees.
Bears have poor eyesight, but they make up for it by having superb hearing and sense of smell. This is a key when dealing with bears. Most bear attacks happen because they are either being startled or because they've smelled something sweet. Bears love sweets, including but not limited to honey.
To counter this, don't be afraid to make noise. Bears do not like people, and if they know a person is around, they will often move away. The exception would be if the bear could smell something sweet. This means you should not leave anything sweet out where a bear can smell it. This includes some colognes and perfumes, incidentally. The general rule is that if you are camping, don't wear either.
Bears have an aversion to fire like many wild animals, though. They don't like the sound or the smell of it. They will often even shun a campfire that has gone out, because it still smells of fire. A campfire is a good deterrent for bears.
Coyotes
Contrary to popular myth, a healthy coyote is seldom a problem in camp, even if you have pets along. They are naturally curious, and many have lost the fear of man, however they are still shy animals. They also don't like fire or loud noises. It is questionable whether a person in camp should even worry if there are coyotes around, as they are likely to watch the campers but seldom to do much more than that.
Porcupines
Porcupines can really put the damper on camping. However, they are even more timid than coyotes and tend to try to be as far from people as they can. If you have a dog with you in camp, just don't let them run free and you should be fine.
Skunks
Skunks are one of the most curious of animals. In skunk country, leaving food out is almost begging skunks to come and explore it. Skunks can inflict a vicious bite, but seldom will if they are treated with respect. They also don't commonly spray if they don't feel threatened. The skunk spray is for defense, and it is the main reason skunks tend not to be afraid of man. They are able to get into almost anything that isn't well sealed, though. Interestingly, they also have a very acute sense of smell.
Raccoons
As cute as raccoons may be, they can be a huge pest. They are capable of giving a bad bite, but most of the problem with them is that they will go through any available food. Never leave fish out, if you are in raccoon country. Ordinarily, they are shy around man, however they love fish so leaving fish out is like a sign pointing the way to invade your camp.
Squirrels and Birds
Healthy squirrels and birds are seldom a real danger, but they will readily eat quite a number of things commonly found in camp, like bread, potato chips (crisps), crackers, fruit, and even dog food. Keeping these in airtight containers is the best way to keep these animals at bay.
Other Predators
Animals such as cougars, wolverines, and badgers occasionally will let their presence be known, but are generally wary of people. Keeping food enclosed and having a campfire is often enough to keep them out of camp.
There are naturally many animals left out of this list, which could be dangerous or bothersome. For instance, deer and elk are both quite capable of killing a person. However, it rarely happens. Still, the best way of dealing with wild animals when camping is to remove reasons for them to visit your camp.
This comes down to three basic things: don't use cologne or perfume, keep the food in airtight containers, and have a well-maintained campfire. Doing this, chances are you will never have problems with the wildlife.