Reaching sexual maturity at 2.5 m, females prepare nests during the dry season either in holes or on mounds of mud or sand (3). After two months of surprisingly gentle courtship, during which the female must reduce the male's territorial aggression by making audible signals and by lifting her head to expose her throat, and nuzzling his head and neck (6), the female lays between 30 and 60 eggs. These are covered with sand and left to incubate under the heat of the sun for 90 days (3). The female guards the nest and assists during the hatching process, which coincides with the start of the annual rains. Both parents may guard the hatchlings (6) although they can fend for themselves immediately (2). Only a few survive due to predation particularly by raccoons (7). Adults make dens, dug 3 – 9 m into the river bank, near their nest site, but move inland during the winter, as they are unable to tolerate water temperatures of much below 18 ºC (6). The American crocodile's diet consists mainly of fish, but birds, small mammals, crabs and turtles are also taken and eaten underwater (3). Crocodiles hunt by waiting motionless in the water until their prey is close enough, then attacking the prey and drowning it. They will even regurgitate small amounts of food to attract fish. During winter, the digestion rate is very slow, so they can go for months without food (2).

A fairly large crocodile species, the American crocodile has a stocky body with a long, powerful tail. The short but muscular legs end in sharp claws (2) and the long triangular snout contains 14 to 15 sharp, conical teeth on each side. The large fourth tooth of the lower jaw fits into a pit in the upper jaw, but remains visible (5). The American crocodile is neatly adapted to life in the water. The ears, eyes and nostrils are located on the top of the head so that nearly the whole body can be submerged (5). A fold of skin can close the windpipe to enable the crocodile to open its mouth underwater and breathe through the nostrils (5). The eyes can be covered with a third eyelid to protect them underwater and the ears are covered with a flap of skin (2). The pupils are vertical slits to help with night vision (2) and there is a distinct swelling in front of each eye (3). Very young American crocodiles are green with dark banding on the back and tail (2) (6). Juveniles are olive green and are no longer banded (6). Adults are dull grey, with a white to yellow belly (2). Compared with other crocodile species, the armour is less prominent. Rows of raised scales contain knobs of bone (5).

American crocodiles live along both the Atlantic and Pacific coasts, from Central America through South America and the Caribbean Islands. They can also be found along the southeastern coast of Florida. Lake Worth and Cape Sable are the most northern limits of the species. They are more commonly found in the lowlands of Florida, and salt-water marshes throughout Central and South America.

Biogeographic Regions: nearctic (Native ); neotropical (Native )

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Range extends from southern Florida, Sinaloa (Mexico), and Yucatan (Mexico) south through Middle America (Pacific and Atlantic) and the West Indies to northern South America (to northern Peru and Venezuela) (Ernst et al. 1999).

Florida: Historical range centered on the southern tip of mainland Florida but extended at least as far north as Sanibel Island and Sarasota County on the west coast and Indian River County on the Atlantic coast, and southward into the Florida Keys (USFWS 2007). The primary historical nesting area in Florida was on the mainland shore of Florida and Biscayne bays, including many of the small islands near shore, in what is today Everglades National Park, and it also included the upper Florida Keys from Key Largo south to Lower Matecumbe Key (see USFWS 2007). Today most nesting occurs on the mainland shore of Florida Bay between Cape
Sable and Key Largo, but the nesting range also includes Biscayne Bay and the upper Florida Keys, with unsuccessful nesting north to Marco Island (USFWS 2007).

Middle America: both coasts from Mexico south to Panama. See Kaiser et al. (2001) for information on a breeding population on Roatan, Honduras.

Antilles: Cuba (Isla de la Juventud, and nearby islands), Hispaniola, Jamaica (along south coast and is especially abundant in marshes of Black River in west), Martinique, and Maragarita. The population in Cuba is of uncertain taxonomic status (see Milián-García et al. 2011 and taxonomy comments).

Northern South America: Venezuela, Colombia, Ecuador, and northern Peru.

Occasional vagrant to Cayman Islands (Schwartz and Henderson 1991).

Gulf of Mexico

occurs (regularly, as a native taxon) in multiple nations

Continent: Middle-America Caribbean South-America North-America
Distribution: USA (S Florida), Mexico (Chiapas) Belize, Costa Rica, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Mexico, Panama,  Cayman Islands, Cuba, Dominican Republic, Haiti, Hispaniola, Jamaica,  Margarita, Martinique, Trinidad, Colombia, Peru, Venezuela  
Type locality: "La grande ile de Saint-Domingue, Antilles, Amerique" (=Hispaniola; most probably the French portion which today is Haiti); restricted to "Santo Domingo, Puerto Plata," by Smith and Taylor (1950: 364); and further restricted to "L'Etang, Saumatre, Haiti," by Schmidt (1953: 111).

Historic Range:

U.S.A. (FL), Mexico, Caribbean, Central and South America

American crocodiles are found along the eastern coast of the Pacific Ocean from western Mexico south to Ecuador, and along the western coast of the Atlantic Ocean from Guatemala north to the southern tip of Florida (6). They are present in southern United States, Central America and northern South America (3).

American crocodiles are moderate sized crocodiles, although some individuals can grow longer than 4 long. There are unconfirmed reports of individuals 7 m long. Males tend to be larger than females. Adults have an olive-brown coloration, whereas younger crocodiles are lighter tan color.  They have a narrow head and a long snout (which distinguishes them from alligators). Their sharp, jagged teeth interlock with each other. They have 28 to 32 teeth in their lower jaw and 30 to 40 in the upper jaw. They also have a protective eyelid that allows them to see underwater and the design of their iris gives them good night vision. American crocodiles are distinctive from other crocodile species in their reduced amount of scaly armor. Their tail is extremely long and powerful, and is used for swimming.

Range mass: 907.2 (high) kg.

Average mass: 220-450 kg.

Range length: 7 (high) m.

Average length: 3.5 m.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: male larger

Length: 460 cm

Syntype for Crocodylus acutus
Catalog Number: USNM 211273
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Sex/Stage: Female; Adult
Preparation: Dry
Year Collected: 1875
Locality: Arch Creek, head of Biscayne Bay, Dade, Florida, United States, North America

Habitat and Ecology

Systems

• Terrestrial
• Freshwater

The habitat of American crocodiles includes a broad range of aquatic environments. They inhabit freshwater, including rivers, lakes and reservoirs, and can also be found in brackish environments, such as example estuaries and swamps. There is also a population in a unique hyper-saline lake in the Dominican Republic. Another unlikely environment where American crocodiles are found is along brackish canals bordering a Florida power plant.  American crocodiles create complex burrow systems to provide them an alternative shelter when they are vulnerable to low water levels. These burrows are used as shelter from cold weather, as hiding places, and as a spot to rest. Crocodiles may make the burrow large enough for movement or they may be as shallow as only two feet below the ground. The entrance to the burrow is built at least partially submerged, if not fully submerged underwater. American crocodiles choose an area based on the reliability of a food source. As long as there is a sustainable amount of food, they do not leave the area, with the exception of mating season.

Habitat Regions: tropical ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams; coastal ; brackish water

Wetlands: marsh

Other Habitat Features: estuarine

Depth range based on 2 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 1.5 - 1.5
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Comments: Habitat includes coastal mangrove swamps, brackish and salt water bays, lagoons, marshes, tidal rivers, brackish creeks; also abandoned coastal canals and borrow pits. Individuals may wander widely in coastal waters and may range inland into lakes and lower reaches of large rivers. American crocodiles occupy mostly nonsaline waters in the nonbreeding season, move to saline waters when breeding. In Florida, primary habitat is inland mangrove swamps protected from wave action; females use open waters of Florida Bay only for access to nesting sites (Kushlan and Mazzotti 1989).

Eggs are laid in a mounded nest of soil, sand, or peat, or in a hole in the ground (Kushlan and Mazzoti 1989). Florida Bay nest sites usually are at edge of hardwood thickets on small sand beaches, or on high marl banks of coastal creeks, or in mangrove swamps along old canal banks; also on berms of power plant cooling canal systems (Gaby et al. 1985). In the West Indies, nests most often are in the ecotone between Conocarpus-dominated riparian strip and xeric uplands (Schwartz and Henderson 1991). In Belize, most nesting areas were on elevated beach ridges of coarse sand; adjacent shallow brackish lagoons provided critical nursery habitat (Platt and Thorbjarnarson 2000). See also Lutz and Dunbar-Cooper (1984).

In Florida, shortly after hatching, hatchlings disperse from nest sites to nursery habitats that are generally more sheltered, have lower salinity (1-20 parts per thousand), shallower water (generally), and more vegetation cover (USFWS 2007). Lazell (1989) reported that young generally occupy brackish water but seem to do well in full salt water on North Key Largo (Florida), perhaps due to the effect of abundant rainfall.

American crocodiles can be found in both freshwater and saltwater habitats, but are most commonly found in tropical wetlands such as mangrove-lined saltwater estuaries and lagoons (6). They construct long burrows to avoid adverse conditions (3).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Crocodiles may make seasonal movements between freshwater and saline habitats (Gaby et al. 1985).

American crocodiles are carnivorous, feeding mostly on fish, frogs, turtles and the occasional bird or small mammal. Juvenile individuals eat more aquatic invertebrates and small fish, while recent hatchlings hunt insects on land. A full digestive cycle from swallowing to excretion takes approximately 72 hours. During hunting, prey is grabbed with their powerful jaws, swallowing it whole. American crocodiles also ingest small stones to aid in grinding up their food.

Animal Foods: birds; mammals; amphibians; reptiles; fish; carrion ; insects; terrestrial non-insect arthropods; mollusks; aquatic crustaceans

Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore , Insectivore , Eats non-insect arthropods, Scavenger )

Comments: Adults are believed to eat primarily fishes (USFWS 1980) but probably also eat large invertebrates and various vertebrates (mammals, birds, turtles). Young feed mainly on aquatic invertebrates (USFWS 1980, Platt et al. 2002).

American crocodiles are top predators in aquatic ecosystems they inhabit. Their waste products and uneaten prey also contribute to other animals in the ecosystem.

American crocodiles are only vulnerable as prey to other predators when they are young. Until they mature to a larger size, the young are vulnerable to raccoons, certain larger fish and wild cats. In order to protect themselves, they attempt to hide and conceal themselves with their surroundings. Later in life their crypsis is useful to prevent detection by prey.

Known Predators:

• racoons (Procyon lotor)
• cats (Felidae)
• large fish (Actinopterygii)

Anti-predator Adaptations: cryptic

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 21 - 80

Comments: This species is represented by at least several dozen occurrences (subpopulations). Occurrences are discontinuous. Most are small, isolated, and in remote areas.

2500 - 100,000 individuals

Comments: Total adult population size is unknown but presumably exceeds 2,500 and may exceed 10,000.

The American crocodile population in Florida has grown to an estimated 1,400 to 2,000 individuals, not including hatchlings, with 91-94 documented nests in 2005 (see USFWS 2007).

As of the 1990s, perhaps 200 adults and subadults existed in the Dominican Republic (Schubert 1994). Others are scattered throughout the range.

In Florida, most nest failures are due to raccoon predation and failure of eggs to hatch (USFWS 1980). Crocodiles in Florida have large (86-262 hectares) overlapping activity areas (Kushlan and Mazzotti 1989).

American crocodiles communicate through vocalizations. Roaring acts to defend territory and attract mates. Territorial communication is also displayed through slapping the water with the head and tail. Infrasonic sound is also used which creates ripples on the water's surface. This infrasonic rumbling is used during the mating season to court potential mates. Young American crocodiles communicate to the mother when hatching time approaches. Newly hatched young emit distress calls eliciting protective measures from the mother. The position of the body is also used to indicate dominance or submission. Dominant males swim along the surface of the water, exposing their entire body, while females and submissive males only expose their head or snout while swimming. Tail-thrashing is also used in aggressive behaviors and interactions as a visual cue. Finally, chemosensory cues are used in communication, but have been poorly documented.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: pheromones

Perception Channels: visual ; tactile ; acoustic ; chemical

Female American crocodiles incubate their eggs to keep them warm. The sex of the offspring is determined by the temperature at which the eggs are incubated. High temperatures of 88 to 91 degrees Fahrenheit produce male offspring, while anything lower than 88 degrees results in females. However, the temperature must remain above 82 degrees in order for the eggs to hatch. After the young hatch, they rely on the yolk of the egg for nourishment for as long as two weeks. As they age the number of potential predators decreases, but newly hatched and young American crocodiles are particularly vulnerable and therefore must hide. The food supply of the yolk keeps them nourished until they are more competent and secure. As they mature and grow, young American crocodiles start to hunt insects on land, much like the foraging style of other lizards.

Development - Life Cycle: temperature sex determination

American crocodiles have the potential to live as long as 100 years, however their average life expectancy ranges from 60 to 70 years.  There is a high mortality rate of offspring. Only 1 in 4 reach the age of 4. This is due to their vulnerability at their hatching size. Young American crocodiles have not yet developed the size and strength necessary to protect themselves from predators. Their vulnerable status along with the lack of parental care puts the young at risk. Also, if nests are built below the water line, flooding can result in mass death of the eggs. In addition, the eggs themselves are at risk to thieves such as raccoons.

Range lifespan

Status: wild: 100 (high) years.

Average lifespan

Status: wild: 60-70 years.

Average lifespan

Status: captivity: 45 years.

Maximum longevity: 32.9 years (captivity)

Courtship takes place in January and February, when males attract females to mate. Courting can last as long as two months. During mating season American crocodiles display territoriality by males engaging each other in competition for access to females. Males roar loudly, raising their heads and opening their mouths, displaying their impressive teeth as part of the mechanism to attract mates. Females respond to male roars with roars of their own.

Mating System: polygynous

American crocodiles breed seasonally between April and May. Female American crocodiles lay 30 to 60 eggs in a hole or a mount that take approximately 9 to 10 weeks to hatch. Eggs are kept warm through the generation of heat from rotting vegetation placed on the eggs. Females guard nests throughout that period. Sexual maturity in American crocodiles occurs at a length of 1.8 to 2.4 meters, or between 8 and 10 years old.

Breeding interval: American crocodiles breed once yearly.

Breeding season: Egg-laying occurs during April or May.

Range number of offspring: 30 to 60.

Range gestation period: 2 to 3 months.

Range time to independence: 2 to 14 days.

Range age at sexual or reproductive maturity (female): 8 to 10 years.

Range age at sexual or reproductive maturity (male): 8 to 10 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous

Females build a nest prior to mating. The nest is constructed in an open area, usually above the high water mark. Females dig nests up to 1.5 m deep and up to 1.8 m in diameter. Once the eggs are laid, usually between 30 and 60, the nest is covered with dirt to incubate and they are not uncovered until they hatch. Although the eggs are placed close together, they are separated from each other to prevent them from breaking. When hatching approaches, the female increases the frequency of her visits to the nest site. While the eggs are hatching, the mother displays her protective nature through aggression. The female will rest her head above the nest, listening for noise from the young that cue her to uncover the nest in preparation for their hatching. Once uncovered, the mother aids the hatchlings in climbing out of the eggs, and later escorts the young to the water when they are ready. Once the young are taken from the hatching site they disperse quickly and are subsequently on their own.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Protecting: Female)

Eggs are laid in April-May in Florida, Mexico, Venezuela, and Honduras; December-February in Ecuador and Panama (Kushlan and Mazzotti 1989); mid-February to early April in Dominican Republic (Fitch 1985); late March-early May in Belize (Platt and Thorbjarnarson 2000). Clutch size is 20-80 (average 38 in Florida, 24 in Hispaniola, 22 in Belize). Incubation averages about 85 days in Florida; female guards nest; eggs hatch in July and August. Hatching occurs April-June in West Indies (Schwartz and Henderson 1991), late June to mid-July in Belize (Platt and Thorbjarnarson 2000). Adult opens nest and may carry hatchlings to water. Parent apparently protects young for unknown duration. Females become sexually mature at an age of around 10-13 years. Clutches are laid singly or communally in southern Florida (Kushlan and Mazzotti 1989).

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There is 1 barcode sequence available from BOLD and GenBank.   Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen.  Other sequences that do not yet meet barcode criteria may also be available.


Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 3
Species With Barcodes: 1

Year Assessed

• Needs updating

Assessor/s

Reviewer/s

American crocodiles are listed as endangered under the United States Endangered Species Act. In addition, American crocodiles are protected under the Convention on International Trade in Endangered Species internationally, which prohibits commercial trade of these animals. In the past, American crocodiles were subject to poaching for their hides, but now the main threat to their existence is loss of habitat due to the invasion of human development and illegal killing.

US Federal List: endangered

CITES: appendix i

IUCN Red List of Threatened Species: vulnerable

United States

Rounded National Status Rank: N2 - Imperiled

Rounded Global Status Rank: G2 - Imperiled

Reasons: Range extends from Mexico and southern Florida to northern South America; populations are small and declining throughout most of range; some populations have been extirpated, and poaching for hides outside the United States continues to pose a major threat.

Other Considerations: USFWS and State of Florida list as Endangered. Also in CITES Appendix.

Current Listing Status Summary

Status: Endangered
Date Listed: 03/20/2007
Lead Region: Foreign (Region 10) 
Where Listed: Entire, except U.S.A. (FL)

Status: Threatened
Date Listed: 10/28/1975
Lead Region:   Southeast Region (Region 4)   
Where Listed: FL pop.


Population detail:

Population location: Entire, except U.S.A. (FL)
Listing status: E

Population location: FL pop.
Listing status: T

For most current information and documents related to the conservation status and management of Crocodylus acutus , see its USFWS Species Profile

The American crocodile is classified as Vulnerable (VU A1ac) on the IUCN Red List 2004 (1), and is listed on Appendix I of CITES, except for in Cuba, where it is listed on Appendix II (4).

Global Short Term Trend: Decline of 10-70%

Comments: Range-wide trends are poorly documented, but in most of the range this species undoubtedly has declined in population size over the past three generations (three generations is at least 45 years and may be as high as 60-75 years).

In Florida, extent of occurrence, area of occupancy, population size, nesting range, and number of known nests have been increasing in recent decades (Mazzoti et al. 2007, USFWS 2007). The maximum number of nesting females in Florida increased from 20 in 1975 to 85 in 2004 (Mazzoti et al. 2007).

See Schwartz and Henderson (1991) and Thorbjarnarson (1988) for information on status in Haiti.

Global Long Term Trend: Decline of 30-50%

Comments: Area of occupancy, number of subpopulations, and especially population size have undergone a major long-term decline, but the degree of decline is uncertain.

Degree of Threat: A : Very threatened throughout its range communities directly exploited or their composition and structure irreversibly threatened by man-made forces, including exotic species

Comments: Major threat in most parts of the range is poaching for skins. In some areas, populations have declined as a result of killing for meat or fat, killing for "fun," collection of eggs, and entanglement in fishing gear (Schubert 1994). Habitat loss is also a threat, especially in Florida. Nesting sites and non-nesting habitat have been lost to development at Miami Beach and in the upper Florida Keys, but this loss has been partially offset by creation of artificial nesting sites on spoil banks along southern Biscayne Bay and a westward addition to nesting range in Florida Bay (Kushlan and Mazzotti 1989). Future threats in Florida include stochastic natural disasters such as hurricanes and cold weather, road mortality, continued habitat degradation, and poaching (USFWS 1998). Crocodiles are sensitive to human presence (especially at nest sites). In Florida, disturbance at nest sites caused females to abandon the site (Kushlan and Mazzotti 1989).

In Florida, crocodiles remain threatened by modification of habitat because of development adjacent to crocodile habitat; they will benefit from restored freshwater flow into estuaries (Mazzoti et al. 2007). As crocodiles increase in abundance and expand into new areas, interactions with humans will occur more frequently; integration of a recovering crocodile population with ever-increasing human use of coastal areas is a major challenge (Mazzoti et al. 2007).

Between the 1930s and the 1960s, American crocodiles were hunted for their skin, which was a popular material for bags and belts (3). American crocodiles were declared endangered in 1979 and are now legally farmed for their skins. Now, the major threat to wild populations is habitat loss as a result of increasing urban development. Illegal hunting and accidental encounters with fishing nets, cars and boats are still a threat (6).

Conservation Actions

Management Requirements: The public should be educated about crocodiles. In Florida, efforts should be made to decrease accidental mortality and restore the natural hydrology of the Everglades. See USFWS (1998) for specific information on recovery and management in Florida.

Management Research Needs: Determine habitat requirements. Research methods of captive breeding and restocking.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Some occurrence are in areas that provide a degree of protection, such as Santa Rosa National Park, Costa Rica; Morrocoy National Park, Venezuela; Everglades National Park, Crocodile Lake National Wildlife Refuge, J.N. "Ding" Darling National Wildlife Refuge, and Ten Thousand Islands National Wildlife Refuge, Florida, USA. See USFWS (1998) for a description of designated critical habitat in Florida.

Needs: Crocodile habitat in Florida continues to need maintainance and enhancement to provide protection for all life stages of the existing crocodile population and to ensure that available habitat can support population growth and expansion (USFWS 2007). Further acquisition of nesting and nursery sites and additional crocodile habitat by federal, state, and local governments and implementation of management on these publicly owned
properties are necessary to ensure protection to crocodiles and their nests and enable expansion of populations size and distribution (USFWS 2007).

Protection from poaching is critical in many parts of the range.

Surveys and research into population statistics and behavioural ecology have proved extremely useful for recovery efforts in the United States, and are hoped to continue for more southerly populations. The American crocodile is fully protected in the majority of its range, but enforcement of this protection is inadequate, and legal hunters of caiman are known to illegally hunt American crocodiles as well. Management programmes have been set up in eight countries within the range, but they are commonly ignored. As well as reducing illegal hunting, crocodile farms can provide individuals for restocking the wild. For example, Venezuela contains much suitable crocodile habitat, but would benefit from restocking (3).

American crocodiles have been known on the rare occasion to attack and kill or injure humans and domestic animals.

Negative Impacts: injures humans (bites or stings)

American crocodiles have no direct economic importance for humans, however, similar species such as Alligator mississippiensis attract tourists to areas such as the Florida Everglades. In some areas they may be hunted for food or leather.

Positive Impacts: food ; body parts are source of valuable material; ecotourism

Comments: See Thorbjarnarson (1999) for a discussion of the limits to sustainable use of crocodilians.

Comments: No subspecies are recognized, although geographic variation exists among populations in Florida, Jamaica, and the Pacific coast. Populations in Florida, Jamaica, and the Dominican Republic differ from each other in their gene frequencies (Menzies and Kushlan 1991). Densmore and White (1991) used molecular data to assess phylogenetic relationships within the Crocodylia, including all species in the genus Crocodylus; the closest relative of C. acutus was C. intermedius by one analysis using rDNA, C. moreletii by another analysis that used both rDNA and mtDNA; overall, New World species of Crocodylus appeared to be more closely related to each other than to species in other parts of the world. See Ernst et al. (1999) for further taxonomic discussion.

Milián-García et al. (2011) examined microsatellite loci plus DNA sequence data from nuclear (RAG-1) and mitochondrial (cytochrome b and cytochrome oxidase I) genes of Crocodylus acutus and C. rhombifer from Cuba. They found that C. acutus from Cuba is more closely related to C. rhombifer than to C. acutus from Central America. Thus current taxonomy does not appear to be an accurate reflection of evolutionary relationships. The researchers also found evidence of hybridization between the two species in Cuba. Further study is needed before taxonomic issues can be resolved. (Milián-García et al. 2011).