Gator Fact Sheet

temperatures rose to such extremes? By Alligators from the Par Pond population have human identification at crime scenes. Using these markers to using the combination of external and also been the subjects of contaminant determine paternity in alligators led to the discovery that about internal temperature-sensitive transmitters, studies. Elevated levels of the radioactive one-third of all gator nests contain offspring from multiple researchers learned that alligators element radiocesium (137Cs) occur in some fathers. In addition, although there are many 8-10 ft (2.4-3 m) responded to thermal cues very rapidly, portions of Par Pond as a result of reactor male alligators in the gator population on the SRS, only the few seeking cooler waters in coves, stream operations. Cesium-137 mimics elemental very large males (11+ ft; 3.4+ m) sire offspring. Finally, edges, or on stream bottoms potassium when incorporated microsatellites have been used in investigations of the effects of once their body temper- into plant and animal tissues; contaminants, leading to the discovery that the Hg and low- ature reached about in animals it tends to levels of radioactive contamination in some alligators on the Federal status The American alligator and some crocodile “Threatened due to similarity of 91°F (33°C). concentrate in muscle SRS are not resulting in increased mutation rates relative to species are prime examples of the concept of The American alligator, Alligator mississippiensis, appearance” to other crocodilian tissue. SREL studies gators from other populations. Continuing research will use “sustainable use.” Sustainable use simply means occurs throughout most of the southeastern United States. Alligators species Like many wildlife concluded that al- these genetic markers to make more discoveries about the that an organism is harvested at levels that can were once hunted primarily to produce leather products, which became Size/age at maturity species, alligators though some indiv- biology of alligators, solve other environmental problems, and be continued indefinitely. The specifics of fashionable in the late 1800s. Untold numbers of animals were killed during 6 ft./dependent on growth rates are vulnerable to iduals had elevated even produce a map of the alligator genome. sustainable use programs vary among croco- decades of unregulated hunting. Even after limited protection was put into effect in Typical maximum size environmental con- levels of 137Cs in their dilian species, and among populations within a some areas in the mid-1900s, animals continued to be poached. As a result, alligator numbers species in different parts of its geographic range. males–13 to 14 feet, taminants. Because bodies, there were no Humans and Alligators were dramatically reduced and in some regions it was feared that local populations would go females–9 to 10 feet alligators are top-level detectable effects on For example, the harvesting program for extinct. Federal legislation in the 1970s and 1980s, including the Endangered Species Act of Largest SRS alligator carnivores, they can bio- individual or population The recovery of alligator populations throughout the Southeast, alligators in Florida differs from programs in 1973 and amendments to the Lacey Act in 1981, ensured the alligator’s protection, and eventually its comeback. Today Louisiana and other southeastern states; even 12’10” male that died in 1996 accumulate contaminants health. combined with human population growth and encroachment alligator numbers are estimated in the millions and they are common throughout most of their historic range. populations in different lakes within Florida are Weight in their tissues through the prey on wetland habitats, has increased the likelihood of gator-human managed differently. The numbers of adult varies; adult males can be items they ingest. Some environmental There is, however, reason for concern about interactions. Even so, the fact remains that the probability of an animals that can be killed, as well as the The story of the American alligator, both tragedy and success, is similar 500+ pounds contaminants can be passed from female human consumption of alligators due to a alligator attacking a proportions of eggs and hatchlings that can be to that of many of its close kin, the crocodiles. Worldwide there are 23 Longevity alligators to eggs, potentially adversely much more widely distributed environ- person is extremely removed from the wild, are based on annual species of crocodilians; most were also hunted for food and skins, 40 or more years in the wild, affecting the health of developing offspring. mental contaminant, mercury (Hg). Point- low. The number of population trends. The end result is that the legal, and by 1971 all crocodilians were endangered, threatened, or declining record 66 years in captivity Scientists at SREL are studying maternal source pollution and atmospheric transport alligators throughout regulated harvest of various life stages does not in numbers. Habitat destruction in many countries exacerbated the Home range size transfer of contaminants from females to of this metal have resulted in many wildlife the range at any given harm the population, and gator and croc declines. But a combination of legislation, effective law enforcement, up to 2,000 acres for their offspring. On the SRS, alligators nest species having elevated Hg levels, even in point in time is populations can thrive even as humans use them dedicated conservationists, and innovative sustainable yield harvesting adult males in a swamp downstream from a coal- “pristine” habitats. High Hg levels are probably more than commercially. In fact, many scientists believe that programs reversed the decline for many species, despite continuing some crocodile species would be in far worse Hatchling size burning power plant. The swamp is common in wetland habitats and in top-level three million animals, habitat loss. Since the 1970s 16 of the 23 crocodilian species have shape, and perhaps would have become extinct, contaminated with a variety of potentially predators. Alligators are therefore prime yet on the average there 8 to 10 inches if there were not a sustainable use management increased in population size. However, some species, such as the Clutch size toxic trace elements including arsenic, candidates for exhibiting high Hg are fewer than 10 program for those species. Carefully managed Chinese alligator, remain highly endangered in the wild. 20–60 eggs cadmium, and selenium (Se). Of these concentrations. Mercury levels in the tissues attacks per year. The sustained-yield harvest programs provide direct Incubation period elements, selenium is of great concern of SRS alligators, as well as those from other majority of attacks have economic benefits to local people and The current federal protection status of the alligator remains as “threatened due to similarity of appearance” to endangered approximately 65 days because it readily bioaccumulates and southeastern wetlands, have been analyzed. occurred in Florida, communities, giving everyone an incentive to crocodiles (and products made from their skin). In some states alligators may be harvested using controlled hunts. Alligators are Teeth causes developmental abnormalities when Although there are no national standards for where there have been protect both the species and its habitat. also bred and raised in captivity for the production of meat and skins, but most of the half million farmed alligators are hatched 74 to 80 transferred from females to developing Hg concentrations in reptile meat, if the 11 fatalities during a from eggs collected from the wild. The products from these tightly regulated wild harvests and alligator farms are now sold legally, Name origin embryos. Monitoring efforts in the same standards that are used for fish were 50-year period. Most This brochure was produced by the Savannah River Ecology providing important funds for the conservation of this species and its habitat. Alligator is derived from the contaminated system revealed that adult applied to alligators (1 mg Hg/kg wet weight attacks occur either because alligators have lost their natural Laboratory Environmental Outreach Program, in support of Spanish el lagarto which means female alligators accumulate Se and of tissue), then a high proportion of fear of humans (due to being illegally fed by people and learning Partners in Amphibian and Reptile Conservation (PARC; Alligator Ecology “the lizard”; mississippiensis transfer significant quantities to their eggs. alligators from the Everglades, other areas to associate humans with food) or because they are defending www.parcplace.org). Printing was sponsored by SREL means “of or belonging to the Concentrations of Se in eggs and hatchlings of Florida, and the SRS would be considered a territory. Humans can do several things to minimize the risk (www.uga.edu/srel/), with additional program support from The Habitat Mississippi” collected from the contaminated site are unsafe for human consumption. of attack: Christensen Fund and the Department of Energy. Text by David Alligators live in fresh and brackish water habitats but will venture into salt Ancestry 3-5 times higher than levels from n Do not feed alligators, thereby causing them to become E. Scott, I. Lehr Brisbin, Jr., Travis C. Glenn, and William A. water. Alligators inhabit swamps, tidal marshes, creeks and rivers, canals, ponds, fossil records of crocodilian uncontaminated samples. Fortunately, the SREL scientists are also developing

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