The fundamental role that reptiles play in the ecosystem is a simple one. As one part of the greater food chain, they prevent overpopulation and provide food for hungry predators, especially when they are young. Their importance to humans is less pronounced but still significant.

Reptiles impose an important check on insect and rodent populations. Some of the most venomous snakes in the world such as the Indian cobra actually prevent the spread of disease-carrying rodents, even in urban centers, so their usefulness often outweighs their danger. However, far more benign reptiles also act to control populations of pests.

According to the website Animal Bytes from Busch Gardens, crocodiles and alligators also prevent overpopulation of fish species in coastal regions and wetlands, which is pivotal in keeping these aquatic ecosystems healthy and balanced. A healthy aquatic ecosystem is instrumental for fisheries that make their living in these environments.

Many reptiles lead very indolent lifestyles, so they attempt to strike quickly to subdue their prey. For any reptile a rotting carcass, which is called a carrion, is an easy meal, so reptiles such as the infamous Komodo Dragon are one of many organisms that play a role in clearing dead animals from the environment.

Reptiles themselves are often used for food. Birds of prey will eat anything from boas to lizards. Young turtles are preyed upon by all manner of animals. Sea turtle hatchlings that face a perilous journey back to the water provide a veritable feast for hungry animals. Nova Southeastern University states that only about one in 1,000 will survive to adulthood.

Though humans generally try to avoid interaction with reptiles, they do occasionally bear an important that extends beyond survival and into the realm of culture. Turtles, for instance, are a delicacy and play a role in traditional Chinese medicine. In addition, the venom of a snake is used often to derive vaccines, and reptile scales are considered fashionable in many cultures.