Spanning the southern tip of the Florida peninsula and most of Florida Bay, Everglades National Park is the only subtropical preserve in North America. It contains both temperate and tropical plant communities, including sawgrass prairies, mangrove and cypress swamps, pinelands, and hardwood hammocks, as well as marine and estuarine environments. The park is known for its rich bird life, particularly large wading birds, such as the roseate spoonbill, wood stork, great blue heron and a variety of egrets. It is also the only place in the world where alligators and crocodiles exist side by side. Leashed pets are allowed in developed areas, such as picnic areas, parking lots, and along gravel and paved roads. Leashes must be no longer than six feet. Pets are not allowed in the buildings or on trails.