Florida is the only place in the world where both crocodiles and alligators coexist. Only one species, the American Crocodile (Crocodylus acutus), is native to the region. Its population is small and highly specific in its distribution, limiting its range to the state’s extreme southern tip. The crocodile’s reliance on particular environmental conditions makes its presence a rare sight compared to the widespread American Alligator. The American Crocodile is currently recognized as a protected species in the United States.
The American Crocodile’s Restricted Range
The American Crocodile’s distribution in the United States is concentrated almost entirely within the subtropical coastal habitats of South Florida. Their home range begins at the southern edge of Miami-Dade County, extends through the Florida Keys, and continues along the southwestern coast into Collier County. The population centers in the mangrove-lined estuaries and sheltered bays of the Everglades National Park and Biscayne National Park.
A significant portion of the breeding population is found in the Florida Keys, particularly around Key Largo, home to the Crocodile Lake National Wildlife Refuge. A notable warm-water refuge is the system of cooling canals at the Turkey Point Nuclear Generating Station near Homestead. While individuals are occasionally sighted in more northern coastal areas, the core population remains confined to the southernmost coastal zone.
Distinguishing Crocodiles from Florida Alligators
Distinguishing the American Crocodile from the American Alligator involves three distinct physical characteristics.
Snout Shape
The crocodile possesses a narrower, triangular or V-shaped snout that tapers toward the tip. In contrast, the alligator has a broader, rounded, or U-shaped snout.
Teeth Arrangement
The most reliable difference involves the arrangement of the teeth when the mouth is closed. A crocodile’s upper and lower jaws are nearly the same width, causing the large fourth tooth on the lower jaw to remain visible outside the mouth. With an alligator, the wider upper jaw completely conceals the lower teeth when the mouth is shut.
Coloration
American Crocodiles tend to have a lighter, grayish-green or olive-brown body color, which helps them blend into the brackish estuaries they inhabit. American Alligators are generally a darker, nearly black color, providing camouflage in the freshwater swamps and lakes found throughout the state.
Unique Environmental Needs
The American Crocodile’s limited Florida range is directly linked to its specialized biological tolerances. Crocodiles are euryhaline, meaning they thrive in high-salinity saltwater and brackish environments. They possess specialized salt glands on their tongues that excrete excess salt, allowing them to inhabit coastal mangrove swamps, estuaries, and barrier islands where alligators cannot establish permanent populations.
The species also requires consistent, warm temperatures, as Florida represents the northernmost extent of their global range. The American Crocodile is susceptible to cold; water temperatures below 45 degrees Fahrenheit can cause it to enter a state of torpor, leading to unconsciousness and potential drowning.
Conservation and Population Recovery
Historically, the American Crocodile population in Florida faced severe threats from habitat loss and hunting, leading to a drastic decline in numbers. By the mid-1970s, the population was reduced significantly, prompting the species to be listed as endangered in 1975. This designation provided legal protection that prohibited hunting and safeguarded their remaining habitats.
Conservation efforts focused heavily on habitat protection, particularly through the establishment of Everglades National Park and Biscayne National Park as protected breeding grounds. Protection of specific nesting sites, including those created inadvertently by industrial activity like the Turkey Point facility, proved instrumental in recovery. These efforts led to a rebound in numbers, resulting in the species being reclassified from endangered to threatened status in 2007.