The Everglades, often described as the “River of Grass,” is a unique subtropical wetland ecosystem spanning a vast area of South Florida. This slow-moving sheet of water flows from the Kissimmee River basin south to Florida Bay, creating a complex mosaic of sawgrass marshes, cypress swamps, and coastal mangroves. The distinct mix of freshwater and saltwater habitats supports an extraordinary level of biodiversity, serving as a haven for nearly 400 species of birds, mammals, reptiles, and fish.
Iconic Reptiles and Diverse Birdlife
The most recognizable inhabitants are large reptiles, particularly the American Alligator (Alligator mississippiensis). This species is considered an ecosystem engineer due to its behavior of digging and maintaining “gator holes” during the dry season. These depressions retain water, providing a refuge for fish, turtles, and insects, which supports other wildlife when the surrounding marsh dries out.
The Everglades is the only place globally where the American Alligator coexists naturally with the American Crocodile (Crocodylus acutus). Alligators are found in the freshwater sloughs and marshes, possessing a broad, U-shaped snout. The more secretive American Crocodile prefers the brackish and saltwater habitats of the coastal estuaries, distinguished by its narrower, V-shaped snout and lighter, grayish-brown color.
The shallow, nutrient-rich waters are a magnet for wading birds, supporting a massive avian population. The area is a critical feeding ground for species like the Great Egret and the vibrant Roseate Spoonbill (Platalea ajaja). The Spoonbill is instantly recognizable by its pink plumage, derived from the carotenoid pigments in the crustaceans it consumes. It uses its unique, spatula-shaped bill as a tactile foraging tool, sweeping it side-to-side through shallow water to snap up small fish, shrimp, and aquatic insects. The success of these bird populations is monitored as an indicator of the ecosystem’s overall health.
Rare Mammals and Aquatic Residents
The Everglades houses a variety of mammals, some of which are highly specialized or threatened. The Florida Panther (Puma concolor coryi) is one of the most endangered mammals in North America, with an estimated wild population of between 100 and 230 individuals. While their range includes the Everglades, their primary breeding habitat is concentrated in the adjacent Big Cypress National Preserve and other lands in southwestern Florida.
The Florida Black Bear (Ursus americanus floridanus) is also present, particularly in the western and northern edges of the wetland, often utilizing the forested upland areas and cypress swamps. This omnivorous subspecies relies heavily on plant matter and invertebrates; approximately 80% of its diet consists of berries, nuts, and saw palmetto hearts. Smaller, semi-aquatic mammals like the North American River Otter (Lontra canadensis) thrive in the watery landscape, using their webbed feet and streamlined bodies to hunt fish and crayfish.
The coastal areas and bays are home to the West Indian Manatee (Trichechus manatus), a large, slow-moving herbivore that grazes on aquatic vegetation. These gentle, warm-water-dependent mammals often venture into the brackish estuarine zones of the Everglades in search of food and warm-water refuges during cooler months. The complex estuarine zone, where fresh and salt water mix, supports diverse fish populations, including sport fish like Snook, Tarpon, and Redfish, alongside freshwater species like Largemouth Bass.
The Impact of Invasive Species
The ecological balance of the Everglades is significantly challenged by the presence of non-native wildlife, most notably the Burmese Python (Python bivittatus). These large constrictors, originally introduced through the exotic pet trade, have established a thriving, reproducing population across the region. Lacking natural predators, pythons have become apex predators, preying on a wide spectrum of native wildlife.
The proliferation of the Burmese Python has been directly linked to catastrophic declines in native mammal populations across Everglades National Park. Scientific surveys have documented a near-total disappearance of species like raccoons and opossums in the core areas of the python’s range, with observed declines of 99.3% for raccoons and 98.9% for opossums. This dramatic reduction in mid-sized mammals disrupts the native food web and alters the structure of the entire ecosystem.
Another concerning invasive reptile is the Argentine Black and White Tegu (Salvator merianae), a large lizard that can grow up to four feet. Tegus are omnivorous and pose a direct threat to native ground-nesting species, consuming the eggs of American Alligators and various turtles. Management efforts, including trapping programs, are underway to control the spread of these invasive reptiles.