U.S. FISH AND WILDLIFE SERVICE|
DIVISION OF ENDANGERED SPECIES
Source Endangered and Threatened Species of the Southeastern United States (The Red Book) FWS Region 4 -- As of
STATUS: Endangered throughout its United States range, Federal Register, September 25, 1975
DESCRIPTION: A large lizard-shaped reptile, the crocodile closely resembles the alligator. Hatchlings are about 23 centimeters in length; adults may grow to 4.5 meters or larger. Florida crocodiles may be distinguished from alligators by their more slender build and their difference in snout shape. The crocodile's snout tapers forward from the eyes while the alligator's snout is untapered and rounded at the end. When the mouth is closed, the fourth tooth in the lower jaw is exposed in the crocodile but concealed in the alligator. The adult crocodile's diet includes fish, crabs, birds, turtles, snakes, and small mammals. The young feed chiefly on aquatic invertebrates and small fish. As a general rule crocodilians feed on any prey items which can be caught and overpowered.
REPRODUCTION AND DEVELOPMENT: Females in south Florida begin nest construction in April, and eggs are laid in late April or early May. Twenty to 6O eggs may be laid in a clutch. Hatching occurs in July and August. One of the parents, presumably the female, opens the nest and assists the young in hatching. There is some evidence that human disturbance of the female while guarding the nest may disrupt the normal behavior pattern of nest protection and assistance to the young during the hatching process. Freedom from human disturbance during this period may be a critical factor to recovery of the crocodile.
RANGE AND POPULATION LEVEL: The American crocodile breeds only in the southern portions of the Everglades National Park, chiefly Florida Bay, and outside the park on adjacent Key Largo, and at Turkey Point. Crocodiles are occasionally reported from the lower Florida Keys on Big Pine, Little Pine, and Howe Keys, with past breeding rumored on Little Pine Key. This lower Keys population exists primarily within the National Key Deer Refuge. Historically the crocodile ranged north on the east coast at least to Lake Worth, Palm Beach County. Breeding is suspected but undocumented for this area. The records do not indicate any difference between current and historic range on the west coast. Present population trends in Florida are clearly down. The estimated population is between 2OO to 4OO individuals with 25 to 3O known breeding females. Over the last decade there has been a slight increase in the number of nests produced.
HABITAT: The crocodile is primarily a coastal species utilizing mangrove swamps, salt and brackish water bays, and brackish creeks. Crocodiles may also enter coastal canals and borrow pits. Nesting occurs primarily in hardwood thickets at heads of small sand beaches and on marl banks along narrow coastal creeks. There is some data to indicate that hatchlings may require brackish or fresh water during their early development, but more recent studies indicate that frequent rainfall is sufficient to supply the water needs of hatchlings. Adults withstand full seawater salinity and wander widely in coastal areas.
CRITICAL HABITAT: The following area (exclusive of those existing man- made structures or settlements which are not necessary to the normal needs or survival of the species) is critical habitat for the American crocodile (Crocodylus acutus) All land and water within the following boundary in Florida: beginning at the easternmost tip of Turkey Point, Dade County, on the coast of Biscayne Bay; then southeastward along a straight line to Christmas Point at the southernmost tip of Elliott Key; then southwest along a line following the shores of the Atlantic Ocean side of Old Rhodes Key, Palo Alto Key, Anglefish Key, Key Largo, Plantation Key, Windley Key, Upper Matecumbe Key, Lower Matecumbe Key, and Long Key, to the westernmost tip of Long Key; then northwestward along a straight line to the westernmost tip of Middle Cape; then northward along the shore of the Gulf of Mexico to the north side of the mouth of Little Sable Creek; then eastward along a straight line to the northernmost point of Nine-Mile Pond; then northeastward along a straight line to the point of beginning.
REASONS FOR CURRENT STATUS: Many crocodile deaths are caused by the direct loss of habitat to urbanization. Other causes, byproducts of urbanization, include human disturbance or intentional killing and accidental deaths in commercial fishing nets and on highways. There is some evidence that decreased fresh water flow into the Florida Bay ecosystem has increased salinities to a point that cannot be tolerated by hatchlings. Heavy predation on hatchlings in Florida Bay, primarily by raccoons, is also thought to be hampering recruitment.
MANAGEMENT AND PROTECTION: The absence of past management programs for the crocodile makes its potential for response to specific measures a largely unknown factor. Beyond the currently available State and Federal legal protection, it appears that a public information program is needed to decrease accidental mortality and increase public tolerance of large, breeding-sized individuals.
U.S. Department of Interior. 1977. Species Accounts for Sensitive Wildlife Information System (SWIS). Compiled by Fish and Wildlife Service, National Wildlife Laboratory, Gainesville, Florida.
**U.S. Fish and Wildlife Service. 1984. American Crocodile Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, Georgia. 37 pp.
For more information please contact:
U.S. Fish and Wildlife Service
31OO University Boulevard, South
Jacksonville, Florida 32216