Hunting affects the environment in contrasting ways. People hunted three species of camel, woolly mammoths and giant armadillos into extinction in North America more than 12,000 years ago -- and that was when hunting was not a sport but a means of survival. Nowadays, most people hunt for sport, often leaving the carcass and taking the head, leaving the remains to decompose.

Across the United States, each state licenses and regulates hunting. Many states allow hunting of specific animals, such as deer, turkey and ducks, but place restrictions on hunters. States set restrictions and limits based on the season, the animal, its population numbers and U.S. Fish and Wildlife status. Depending on the animal, some states also place restrictions on which sex and how many animals a hunter can kill. All of these restrictions help keep populations from dropping too low. In scenarios where natural predators don't exist, if hunting was not allowed, some animals might overpopulate a region.

Because hunters are only allowed to pursue specific species, some environmentalists argue that hunting creates an imbalance in the natural elements of the environment. If a predator, like wolves or mountain lions, are hunted to lower numbers, their prey often increase in number. Nature has a delicate balance and human hunting can have an impact on that natural balance. Opponents to hunting claim that animals have their own ways of population control and humans are not needed to aid that process.

The University of Michigan predicts over hunting will be the cause of extinction in about 25 percent of all animal extinctions during the 21st century. Whales and some African animals have become endangered due to hunting issues. Even with hunting restrictions in place, poaching, which is illegal hunting, is still an issue. In less populated areas, it can be difficult to catch and punish those who are over hunting a particular species.

Hunters may take animals out of the environment, which could have a negative impact on the environment, but they also often contribute to the environment in a positive manner. The fees collected by the individual states for hunting licenses, park permits and other fees are often used to improve the environment. Some hunters also contribute on their own to environmental organizations that conserve and preserve wildlife and natural areas.