(DRAFT) - Taxonomy
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
TAXONOMY
NAME - CROCODILE, AMERICAN
OTHER COMMON NAMES - CROCODILE and AMERICAN;CROCODILE
ELEMENT CODE -
CATEGORY - Reptiles
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - REPTILIA,
ORDER AND SUBORDER - CROCODYLIA,
FAMILY AND SUBFAMILY - CROCODYLIDAE,
GENUS AND SUBGENUS - CROCODYLUS,
SPECIES AND SSP - ACUTUS,
SCIENTIFIC NAME - CROCODYLUS ACUTUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
American Crocodile
Crocodylus acutus Cuvier, 1807
KINGDOM: Animal GROUP: Reptile
PHYLUM: Chordata CLASS: Reptilia
ORDER: Crocodylia FAMILY: Crocodylidae
A large greenish-gray crocodilian with black mottling.
Hatchlings measure approximately 24 cm, and adults may reach lengths
in excess of 4.6 m in Florida. A lateral indentation of the upper jaw
leaves the fourth tooth of the lower jaw exposed when the mouth is
closed. Compared to the alligator, the American crocodile may be
distinguished by its longer, more tapering snout and the exposed
fourth tooth of the lower jaw.
In addition to the present treatment as Crocodylus acutus Cuvier
1807, Florida populations have also been reported as Crocodilus
floridanus Hornaday 1875 and Crocodilus americanus Boulenger 1889
(26).
Descriptions, photographs and/or drawings are available in Ogden
1978a (21), Ogden and Singletary 1973 (23), and Wermuth and Mertens
1961 (26). Preserved and skeletal material is available in the
Florida State Museum, Gainesville, FL and the U.S. National Museum,
Taxonomy - 1 (DRAFT) - Taxonomy
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
Washington, D.C. among others.
Taxonomy - 2 (DRAFT) - Status
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
STATUS
Coded Status
Florida; Federal Endangered
Florida; Officially Listed
E: Federal Endangered
Commercial
Ornamental
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The American crocodile (Crocodylus acutus) has been designated an
Endangered species pursuant to the Endangered Species Act of 1973 (50
CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as
amended. The species has this status wherever found including the
U.S.A (FL), Mexico, South America, Central America, and the
Caribbean. Critical Habitat has been designated in Collier, Dade, and
Monroe Counties, Florida (50 CFR 17.95(c)).
This species is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD (COE) -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
NPS -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public lands under their control. Also responsible
for conservation (Nat. Park System Organic Act - 16
U.S.C. 1, 2-3)/management/recovery on National Park
Service lands. Taking, possessing, or disturbing of
Federally listed species is prohibited on NPS lands
Status - 1 (DRAFT) - Status
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
(36 CFR 2.1, 2.2, and 2.3).
The U.S. Army Corps of Engineers administers the permit program
within the species' range pursuant to Sec. 10 of the River and Harbor
Act of 1899 and the Clean Water Act amendment of 1977. Various other
federal agencies (Farmer's Home Administration - Rural Electrification
Administration, Environmental Protection Agency, Federal Highway
Administration) impact the habitat through development within the
range of the American crocodile via grant programs for water
development, electrical service, sewage treatment, and highway
construction.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Florida
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Game and Fresh Water Fish Commission
STATE STATUTES: Florida Endangered and Threatened Species Act of
1977, Section 372-072, Florida Statutes.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The American crocodile is listed in Appendix I of the Convention
on International Trade in Endangered Species of Wild Fauna and Flora.
Commercial hunting of all crocodilians is prohibited in Mexico.
The Cuban population is protected from hunting in certain areas of
Cuba by "Resolution No. 21-79". The species is listed in the 1981
IUCN Red Book on reptiles.
ECONOMIC STATUSES:
Although the species was previously hunted for its hide, there
are no current legal commercial uses. The species has educational,
scientific, and aesthetic value to man. Crocodiles have also been
hunted because of perceived threats to man.
75/09/25:40 FR 44151/ - Listing in Florida
76/06/16:41 FR 24367/ - Proposed CITES II
76/09/24:41 FR 41915/ - CH determined
77/02/22:42 FR 10462/10488 - Final rule - CITES II
77/08/11:42 FR 40413/ - CH update/correction
79/05/01:44 FR 25480/25481 - Final rule-move from CITES II to CITES I
79/12/18:44 FR 75076/ - Listing throughout range
85/07/22:50 FR 29901/29909 - Five year review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
TERRESTRIAL
COASTAL
LAND USE -
Streams and Canals
Lakes
Bays and Estuaries
Forested Wetland
Nonforested Wetland
Beaches
Strip Mines, Quarries, and Gravel Pits
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
2EM
Lacustrine, littoral EM2
Estuarine, intertidal SS7
Estuarine, intertidal SS3
Estuarine, intertidal FO3
Estuarine, intertidal EM6
Estuarine, intertidal BB2
Estuarine, subtidal UB
Estuarine, subtidal RB1
Estuarine, subtidal OW0
Estuarine, subtidal AB2
Estuarine, subtidal AB1
COMMENTS ON HABITAT ASSOCIATIONS -
The American crocodile is a principally estuarine species, at
least within the U.S. and Caribbean portions of its range. It
frequents mangrove swamps and low energy mangrove lined shorelines
(13,16,17,25), but may occasionally penetrate short distances inland
into fresh water habitats (16,17,24). Nesting sites are on well
drained soils adjacent to relatively deep water (22); these may
include sand/shell beaches, stream banks and canal spoil banks (13,
17,22). Habitats adjacent to the more sheltered nesting areas may be
used year round, but exposed sites along high energy shorelines are
typically avoided except during the nesting season (16,17,22).
The American crocodile is a tropical species, which may be killed
by exposure to freezing weather (02,06,16). It is euryhaline, having
been observed in the wild at salinities of 0-89 ppt (17). Juveniles
weighing less than 200 gm show reduced growth rates at salinities
above 50% seawater unless supplemental water is available, as, for
example, from rainfall (07,08,09,10,16).
Habitat Associations - 1 (DRAFT) - Food Habits
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
LIFESTAGE FOOD FOOD PART
General Arthropods
General Crustaceans
General Fish
General Amphibia
General Reptilia
General Aves
General Mammalia
General Carrion
Food Habits - 1 (DRAFT) - Environment Associations
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Coastal Wetlands: Mangrove swamps
G Coastal Features: Vegetated offshore islands
G
G
Environment Associations - 1 (DRAFT) - Life History
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Crocodiles are opportunistic predators, eating whatever animals
they can catch. Juveniles eat fish, snakes, crabs, and other small
invertebrates (13,17,21,25). Adults eat fish, snakes, turtles, birds,
small mammals and crabs (13,17,21,25).
HOME RANGE/TERRITORY:
Males are territorial during the breeding season (11,14).
Females are possibly territorial at nest site (01), although use of a
nest mound by more than one female apparently occasionally occurs (17,
24,25). Reported home ranges vary from 14-262 ha (16) and overlap
(13,16,20).
PERIODICITY:
The American crocodile is crepuscular and nocturnal, generally
inactive by day; typically active from shortly before sunset to
shortly after sunrise (14,16,25).
MIGRATION PATTERNS:
Non-migratory.
COVER/SHELTER REQUIREMENTS:
At sites along streams or canals where the banks are sufficiently
high, adults may excavate burrows, with the entrance located at or
near the surface of the water (06,12,20,21). Hatchlings in more
exposed situations seek shelter during the day in beach wrack or among
mangrove roots (16).
REPRODUCTIVE SITE REQUIREMENTS:
Nesting occurs on well drained sites adjacent to relatively deep
water. These may be at the heads of beaches or on the banks of
streams and canals. Nests are constructed of the available soil, and
no special effort is made to incorporate vegetation. The soil may be
marl, sand or mangrove peat (13,17,22).
REPRODUCTIVE CHARACTERISTICS:
Females reach sexual maturity at an approximate size of 2.25
meters (16), a size reached at an age of approximately 10-13 years
(15,17). Age and size to sexual maturity in males is unknown.
Maximum breeding age is unknown, but reproductive senility may occur
(17,22). Courtship and mating occur from February to March (11,17,
18). Mating is promiscuous (11). Nesting occurs during late April to
early May (13,16,17,21,22). Incubation takes approximately three
months (13,14,17). Reported clutch size ranges from 19 to 81 eggs
(22), although the larger clutches may represent the combined clutches
of more than one female (13,17,24). Mean clutch size is about 35-45
(13,17,22).
PARENTAL CARE:
The female visits the nest periodically during incubation (17,
18,20,22) and ultimately opens the nest to release the young (23),
Life History - 1 (DRAFT) - Life History
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
but defense of the nest against man is unknown (13,17,19,20,25). The
young are precocial, and parental care after hatching is unknown (13,
16,17). The young may remain together loosely for several days to a
few weeks following hatching (14,16,17), but they are rarely seen with
adults (13,14,16,17).
POPULATION BIOLOGY:
Current limiting factors are not known; possible contributing
factors are low hatchling survival in some areas, highway mortality,
malicious killing and natural catastrophes such as drought or flooding
during nest incubation (16,22). Hatchling survival appears to be low
in Everglades National Park (16), but appears to be fairly high in the
more sheltered environs of north Key Largo (17). Reported sex ratio
is biased 2:1 in favor of females (16), but this may in part result
from sampling bias (17). The sex ratio at Turkey Point Power Plant
is only 1.3:1 females/males (27). Longevity and turnover rates are
unknown. The population density objective is to increase the number
of nesting females in the United States population to approximately 60
individuals (25).
SPECIES INTERRELATIONSHIPS:
None.
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 2 (DRAFT) - Management Practices
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling/Restricting Boating Activities
Beneficial Controlling/Restricting Off-Road Vehicles
Beneficial Restricting/regulating human disturbance of populations
Beneficial
Beneficial Developing/maintaining/protecting wetlands
Beneficial Controlling/Restricting Mining
Beneficial Controlling/Restricting Road Maintainance Actions
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Water Right Acquisition
Beneficial Creating Artificial Habitat/Nesting Structure
Beneficial Reforestation
Beneficial Controlling/Removing Nonnative Vegetation
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting Wild Eggs/Wild Seeds
Beneficial Rehabilitating Individuals
Beneficial Controlling/Removing Native Vertebrates
Adverse Harassment/Vandalism/Indiscriminate Killing
Existing Harassment/Vandalism/Indiscriminate Killing
Adverse Collecting
Existing Collecting
Adverse Boating
Existing Boating
Adverse
Existing
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Draining wetlands, marshes, ponds, lakes
Existing Draining wetlands, marshes, ponds, lakes
Adverse Shoreline modification/development
Existing Shoreline modification/development
COMMENTS ON MANAGEMENT PRACTICES -
During the late 19th century and the first half of the 20th
century, many Florida crocodiles were collected for museums and live
exhibits (03,04,05,06,12). The species was legally hunted in
Florida until about 1962 (17). Formerly occupied habitats from Lake
Worth, Palm Beach County south to central Biscayne Bay, Dade County
have been largely destroyed by urbanization, and crocodiles have been
essentially extirpated from these areas (04,25). Similarly,
development has led to the extirpation of crocodiles from most of the
Florida Keys (17,22,25). Indirect disturbance by apparently innocuous
human activities such as camping, fishing, and boating, may adversely
affect nesting. Observations suggest that repeated close human
presence may cause female crocodiles to abandon or relocate nests or
nest sites (25). Both hurricanes (22) and catastrophic freezes (02,
06,16) may have resulted in some mortality, but their overall
Management Practices - 1 (DRAFT) - Management Practices
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
significance is unclear (16). Some laboratory studies have suggested
that hatchlings are unable to tolerate salinities > 50-75 percent
seawater (07,08,09,10), but under conditions of normal rainfall they
seem to tolerate salinities at least as high as 100% seawater (16,17).
Malicious killing and highway mortality continue to account for
several deaths annually (16,17).
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1984. Recovery Plan for the
American Crocodile. U.S. Fish and Wildlife Service, Atlanta, GA.
26 pp.
The approved Recovery Plan strategy is to establish secure
habitat for all phases of the life cycle, and to establish
self-sustaining populations at natural carrying capacity in
appropriate habitats. The plan calls for research to determine
habitat needs, habitat distribution, ownership, and habitat
availability to crocodiles. Acquisition of important habitat is
essential in assuring recovery. Management options include control of
man-related mortality, educating the public, increasing recruitment by
captive propagation and release, reducing natural mortality and
protecting nest sites.
Ongoing conservation/recovery actions include continuing
acquisition (FWS) at Crocodile Lake NWR, nest monitoring by the
Florida Game and Fresh Water Fish Commission, and in 1984,
installation of crocodile highway crossing signs to reduce highway
related mortality, and studies on the effects of water levels on
creek nests in Everglades NP (28).
Management Practices - 2 (DRAFT) - References
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Alvarez del Toro, M. 1974. Los crocodylia de Mexico (estudio
comparativo). Instituto Mexicano de Recursos Naturales Renovables,
Mexico, D. F.
02 Barbour, T. 1923. The crocodile in Florida. Occas. Pap. Mus.
Zool., Univ. Michigan 131:1-6.
03 Cory, C. B. 1896. Hunting and Fishing in Florida. Estes and
Lauriat. Boston, MA. 304 pp.
04 DeSola, C. R. 1935. Herpetological notes from southeastern
Florida. Copeia 1935 (1):44-45.
05 Dickinson, W. E. 1953. In quest of an adult crocodile.
Everglades Nat. Hist. 1(4):151-156.
06 Dimock, A. W. 1915. Florida enchantments (Revised edition).
Outing Publ. Co., Peekamose, NY. 388 pp.
07 Dunson, W. A. 1970. Some aspects of electrolyte and water balance
in three estuarine reptiles, the diamondback terrapin, American and
"salt water" crocodiles. Comp. Biochem. Physiol. 32:161-174.
08 Dunson, W. A. 1980. Osmoregulation of crocodiles in Everglades
National Park. S. Fla. Res. Ctr. Report T-599. Everglades
National Park, Homestead, FL.
09 Dunson, W. A. 1982. Salinity relations of crocodiles in Florida
Bay. Copeia 1982(2):374-385.
10 Evans, D. H. and T. M. Ellis. 1977. Sodium balance in the
hatchling American crocodile, Crocodylus acutus. Comp. Biochem.
Physiol. 58A:159-162.
11 Garrick, L. D. and J. W. Lang. 1977. Social signals and behaviors
of adult alligators and crocodiles. Amer. Zool. 17:225-239.
12 Hornaday, W. T. 1914. Pages 18-20. The American Natural History.
Vol. IV - Reptiles, amphibians and fishes. Charles Scribner's
Sons, NY.
13 Kushlan, J. Personal communication. Dept. Biology, East Texas
State University, Commerce, TX 75428.
14 Lang, J. W. 1975. The Florida crocodile: Will it survive?
Chicago (Field) Mus. Nat. Hist. Bull. 46(8):4-9.
15 LeBuff, D. R., Jr. 1957. Observations on captive and wild North
American crocodilians. Herpetologica 13:25-28.
16 Mazzotti, F. J. 1983. The ecology of Crocodylus acutus in
Florida. Ph.D. diss. Pennsylvania State University. xiii +
161 pp.
17 Moler, P. Personal communication. Florida Game and Fresh Water
Fish Commission, 4005 S. Main St., Gainesville, FL 32601.
18 Moore, J. C. 1953a. The crocodile in the Everglades National
Park. Copeia 1953(1):54-59.
19 Moore, J. C. 1953b. A mound on a key in Florida Bay, Everglades
Nat. Hist. 1(2):67-75.
20 Neill, W. T. 1971. The Last of the Ruling Reptiles. Columbia
Univ. Press, New York and London. xvii + 486 pp.
21 Ogden, J. C. 1978a. American crocodile. Pages 21-22. IN: R. W.
McDiarmid (ed.). Rare and endangered biota of Florida, Vol. 3:
amphibians and reptiles. Univ. Presses of Florida.
References - 1 (DRAFT) - References
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
22 Ogden, J. C. 1978b. Status and nesting biology of the American
crocodile, Crocodylus acutus (Reptilia,Crocodylidae) in Florida.
J. Herpetol. 12(2):183-196.
23 Ogden, J. C. and C. Singletary. 1973. Night of the crocodile.
Audubon 75:32-37.
24 Patty, P. Personal communication. 162 Dove Creed Dr., Tavernier,
FL 33070.
25 U.S. Fish and Wildlife Service. 1984. American crocodile recovery
plan. U.S. Fish and Wildlife Service, Atlanta, GA 37 pp.
26 Wermuth, H. and R. Mertens. 1961. Schildkroten krokodile
bruckenechsen. Veb Gustav Fischer Verlag Jena. xxvi + 422 pp.
27 Gaby, R., M.P. McMahon, F.J. Mazzotti, W.N. Gillies, and J.R.
Wilcox. 1985. Ecology of a population of Crocodylus actus
at a power plant site in Florida. J. Herpetology 19(2):189-198.
28 Mazzotti, F.J. 1986. Monitoring nest success of American
crocodiles in Everglades National Park in 1986. Final report
to Penn. Coop. Fish and Wildl. Res. Unit, Univ. of PA. 15 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Barbour, T. 1923. The crocodile in Florida. Occas. Pap. Mus.
Zool., Univ. Michigan 131:1-6.
02 Barbour, T. 1944. That Vanishing Eden. A naturalist's Florida.
Little, Brown & Co. 250 pp.
03 Campbell, G. 1980. Croc. Island Reporter. February 15, 1980.
Pages B1-B3. (Newspaper - Sanibel Island, FL)
04 Campbell, H. W. Personal communication. U.S. Fish and Wildlife
Service. Deceased.
05 Carr, A. F., Jr. 1940. A contribution to the herpetology of
Florida. Univ. Fla. Publ., Biol. Sci. Ser., 3:1-118.
06 DeSola, C. R. 1935. Herpetological notes from southeastern
Florida. Copeia 1935(1):44-45.
07 Dimock, A. W. 1915. Florida Enchantments (Revised edition).
Outing Publ. Co., Peekamose, NY. 338 pp.
08 Gaby, R. Connell and Assoc. Personal communication. P.O. Box
341939, Coral Gables, FL 33134.
09 Hornaday, W. T. 1914. The American Natural History. Vol. IV -
Reptiles, amphibians, and fishes. Charles Scribner's Sons, New
York. Pp. 18-20.
10 Key Deer/Great White Heron National Wildlife Refuge. Field office
records.
11 King, F. W., H. W. Campbell, and P. E. Moler. 1982. Review of the
status of the American crocodile. Pages 84-98. IN: Proc. 5th
Working Mtg. Croc. Spec. Grp. Species Survival Commission,
Internat. Union Cons. Nat. and Nat. Res. IUCN, Gland, Switzerland.
12 Kushlan, J. Personal communication. Dept. Biology, East Texas
State University, Commerce, TX 75428.
13 Lawrence, L. Personal communication. Florida Game and Fresh Water
Fish Commission, 4005 S. Main St., Gainesville, FL 32601.
14 Moler, P. Personal communication. Florida Game and Fresh Water
Fish Commission, 4005 S. Main St., Gainesville, FL 32601.
15 Ogden, J. C. 1978. Status and nesting biology of the American
References - 2 (DRAFT) - References
Species CROCODILE, AMERICAN
Species Id ESIS154001
Date 14 MAR 96
crocodile, Crocodylus acutus (Reptilia, Crocodylidae) in Florida.
J. Herpetol. 12(2):183-196.
16 U.S. Fish and Wildlife Service. 1984. American crocodile recovery
plan. U.S. Fish and Wildlife Service, Atlanta, GA. 37 pp.
References - 3