CONSERVATION:
American alligators are probably the best studied species of crocodilian, and there is a large amount of literature available on most aspects of its biology, behaviour and ecology. Population surveys are extensive and ongoing, and data are available throughout the alligators' range due to links with management and harvest programs. While populations were severely affected in the early parts of the century (with protection occurring in the early 1960's), the recovery of this species has been remarkable in most areas thanks mainly due to properly controlled and monitored conservation and sustainable use (eg. tourism, harvesting) programs. The belly skin of the alligator produces a generally high-quality leather, and this resulted in considerable hunting pressure earlier in the 20th century, particularly in Louisiana and Florida. Even after hunting was prohibited in Florida, illegal poaching continued into the 1970s. Were it not for additional changes in the law to control the movement of hides, many think extinction may have been possible. Since then, populations have improved considerably (ie. millions) and are now only considered to be threatened in a few areas by habitat degradation (including water management programs). Alligators have more recently (1979) been downgraded from IUCN listing, while CITES Appendix II classification remains to assist control in trade of other crocodilian species whose skins are similar in appearance.
In some areas, increasing alligator populations cause problems with human populations on the edge of alligator habitat, and 'nuisance alligator' programs are required to deal with them. These involve catching and removing animals which have roamed too far into human habitation, or which pose a potential threat to people. Some animals are relocated, but this has generally been shown to be ineffective as alligators often return to their home range within a matter of days. Most recent "nuisance alligator" programs either sell the animals to a farm, or use their skins to help fund the program. Given the high degree of human-alligator contact, some attacks have been reported, but these are very rarely serious. There have only been a handful of alligator-related fatalities recorded in the USA since the 1950s, and improved education and awareness is the best long-term way to avoid future incidents. An increase in recent attacks have been attributed to illegal feeding of alligators, making them less wary of humans, bolder, and more likely to attack instead of flee.
Large-scale captive and wild sustainable harvest programs (eg. over 150 farms) are well established in several states (e.g. Florida, Louisiana, Texas). This involves captive rearing, ranching and direct cropping of wild populations (eggs and adults), but all linked to proper monitoring programs. The difference between the historical hunting that nearly led to extinction and modern harvest programs is simple: today, there are very strict quotas and controls that prevent wild populations from being adversely affected. Alligators have proven themselves to be highly resilient to both natural and induced mortality, and harvest has many indirect conservation benefits not just for alligators but for entire habitats. Cropping is only allowed from certain populations, protecting peripheral populations that are still recovering. Ranching programs usually have to return a high percentage (17% in Louisiana) of juveniles back into wild populations, although recovery in these areas has now been documented and further reintroduction is likely unnecessary. Alligators have been successfully reintroduced or restocked in several states (e.g. Arkansas, Mississippi). Alligator hunting is allowed in several states under strict quota or licence guidelines. In Florida, the results of harvesting have shown that up to 13% of subadult to adult animals, plus all the eggs from 50% of all located nests, can be safely removed from the alligator population annually without affecting population stability. These kinds of figures are vitally important for proper management programs for alligators and other species.
Several areas of research still require attention, including more work on population dynamics. Much has been learned in the last few years, but management programs rely upon a sound grasp of what populations do in the wild under different circumstances. The state of the wild alligator populations provides ample opportunity for such research to be undertaken. An examination of the effects of cropping and ranching is also possible. Other research taking place involves looking at captive husbandry techniques. These findings have implications for other crocodilian species. Although habitat modification is often to the detriment of crocodilians, proper management can benefit local populations. In Louisiana, weirs and impoundments have been constructed to allow for better water and salinity control of areas of marshland. Increased alligator populations are the result in areas where these controls have been implemented.
Alligators have been shown to be an important part of their ecosystem, and are thus regarded by many as a 'keystone' species. This encompasses many areas from control of prey species to the creation of peat through their nesting activities. Several other species benefit from the presence of alligator nests, not least the Florida Red-bellied turtle (Chrysemys nelsoni) which incubates its own eggs there (up to 200, from more than one individual). The creation of 'alligator holes' is of great value not only to the alligators, but to the other species of animals which use them. For these animals, the value of the refuge outweighs any additional risks from their creators. Alligators in some areas are also showing greatly increased levels of mercury, an indicator of the state of the ecosystem. This may have long-term implications for their ability to reproduce, but the effects are still being quantified.
MORE INFORMATION:
For more information on conservation initiatives for this species, see the CSG Action Plan resource.
MISCELLANEOUS FACTS:
American alligators hibernate during the winter in burrows (or "dens") that they construct, but may occasionally emerge during brief spells of warmer weather.
Alligators do not feed during the cooler months. Studies in captivity have shown that alligators generally begin to lose their appetite below 27°C (80°F), and stop feeding altogether below 23°C (73°F). They can easily last the winter on their energy reserves.
Adult alligators can survive freezing conditions if they are in water. They submerge their body but keep their nostrils projecting above the water surface, so that when the surface freezes they can still breathe (called the "icing response"). Essentially their upper body becomes trapped in the ice. However, occasionally alligators may be trapped completely below ice, and have been known to survive for over 8 hours without taking a breath, because the freezing water slows their metabolic rate down to very low levels. Yet another example of their amazing ability to survive.
As of May 2006, there have been 19 confirmed fatalities caused by alligators in the State of Florida since records began in 1948.
SIGNIFICANT REFERENCES:
Brandt, LA (1991). Long-term changes in a population of Alligator mississippiensis in South Carolina. J. Herpetol. 25(4): 419-424
Brisbin, IL, Ross, CA, Downes, MC, Staton, MA & Gammon, B (1986). A Bibliography of the American Alligator. Savannah River National Environmental Research Park. 310 pp.
Brisbin, IL, Standora, EA & Vargo, MJ (1982). Body temperature and behavior of American alligators during cold winter weather. Am. Midl. Nat. 107: 209-218
Elsey, RM, Joanen, T & McNease, L (1994). Louisiana's alligator research and management program: an update. In: Crocodiles. Proceedings of the 12th Working Meeting of the Crocodile Specialist Group. IUCN, Gland, Switzerland. pp. 199-229
Garrick, L, Lang, J & Herzog, HA (1978). Social signals of the American alligator. Bull. Amer. Mus. Nat. Hist. 160: 155-192
Hunt, RH, Ogden, JJ (1991). Selected aspects of the nesting ecology of American alligators in the Okefenokee swamp. J. Herpetol. 25(4): 448-453
Hunt, RH & Watanabe, ME (1982). Observations on the maternal behavior of the American alligator, Alligator mississippiensis. J. Herpetol. 16(3): 235-239
Kushlan, JA, & Simon, JC (1981). Egg manipulation by the American alligator. J. Herpetol. 15(4): 451-454
Lee, JR, Burke, VJ, & Gibbons, JW (1997). Behavior of hatchling Alligator mississippiensis exposed to ice. Copeia 1997(1): 224-226
McIlhenny, EA (1935). The Alligator's Life History. Christopher Publishing House, Boston.
Rootes, WL, Chabreck, RH (1993). Reproductive status and movement of adult female alligators. J. Herpetol. 27(2): 121-126
Vliet, K (1989). Social displays of the American alligator (Alligator mississippiensis). Amer. Zool. 29: 1019-1031