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| Subspecies: | Unknown |
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| Est. World Population: | 750000-1060000 |
| CITES Status: | NOT LISTED |
| IUCN Status: | Least Concern |
| U.S. ESA Status: | NOT LISTED |
| Body Length: | |
| Tail Length: | |
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| Jumping Ability: | (Horizontal) |
| Life Span: | in the Wild |
| Life Span: | in Captivity |
| Sexual Maturity: | (Females) |
| Sexual Maturity: | (Males) |
| Litter Size: | |
| Gestation Period: | |
The ecology of A. mississippiensis is one of the best-known of all crocodilian species (see Joanen and McNease 1987; Mazzotti and Brandt 1994). Maximum adult sizes rarely exceed 4.5 m total length (TL) for males and 3.0 m TL for females (Woodward et al. 1995; Brunell et al. 2015). The name “alligator” presumably derives from a corruption of the Spanish word “el lagarto”. The work of McIlhenny (1935) in Louisiana was among the first to document some of the remarkable aspects of the natural history of this species. Studies on alligator social behaviour have demonstrated a remarkable degree of complexity in the species’ ability to communicate vocally, through bellows and headslaps, and visually through a complex series of body postures (Garrick et al. 1978; Vliet 1989, 2001).
Females become sexually mature at 1.8-2.1 m TL and 10-16 years of age depending on climate and habitat productivity (Joanen and McNease 1989; Woodward et al. 1992; Wilkinson et al. 2016). Courtship and mating take place during the spring (April-May) warming period. Nest construction and egg-laying occur in June and early July (Joanen and McNease 1989; Woodward et al. 1989). Females construct a mound nest of vegetation or peat and lay an average of 30-50 eggs, depending on age and size of the female, and habitat quality. Incubation of eggs takes 63-84 days, depending on temperature (Lang and Andrews 1994), and young hatch in late August or early September. Females typically open the nest to help the young emerge, and will remain near the pod of hatchlings for up to 9 months and sometimes longer. In some cases, hatchlings overwinter with the female in dens, a burrow they excavate in thick vegetation or mud.
In some habitats, alligators use dens as refuges during droughts or winter freezes for protection against severe weather conditions. In marsh ecosystems, alligators create and maintain small ponds, called “alligator holes”, which play an important ecological role by providing both wetter and drier habitats for alligators and other organisms (Campbell and Mazzotti 2004). Alligators are one of the most temperate species of crocodilians, and are known to survive short spells of below-freezing weather by resting in shallow water with their snouts at the surface, thus keeping a breathing hole open in the surrounding ice (Brisbin et al. 1982).
Alligators are listed on Appendix II of CITES and as Threatened on the US Endangered Species Act. International trade is regulated by the U.S. Fish and Wildlife Service through CITES. However, on-the-ground conservation and management is delegated to each U.S. state which sets protective and harvest regulations. The alligator benefits from a very large number of protected habitats in state and national parks and other protected areas, but a large proportion of the population occurs in unprotected habitat and on privately-owned lands. Conservation has been achieved by protecting key habitat, regulating harvest at sustainable levels and providing economic incentives for private land-owners to maintain habitat. A constituency of individuals and business interests that derive benefit from alligators support their conservation and provides funding, both directly and by use and access fees, to support conservation. Effective management of 'nuisance alligators' has also broadened public support and tolerance of alligators, despite instances of alligator predation on pets, livestock and occasionally humans. Recommendations for research and conservation to address current and future threats include:
1. Investigations on the effects of water management in the Everglades ecosystem: The construction of a network of canals in the greater Everglades ecosystem of Florida during the early part of the 1900s altered hydrological patterns and the long-term productivity of alligators in that ecosystem. Alligator ecology investigations, as part of the Comprehensive Everglades Restoration Plan, have been conducted since the 1990s and are still underway to measure the long-term effects of hydrological restoration of this ecosystem (Mazzotti et al. 2009).
2. Research on human dimensions in alligator conservation: Alligators present a bone fide safety threat to humans and their domestic animals. State alligator management programmes have been challenged in recent years with trying to maintain public safety while keeping alligator populations at levels that conserve the species and allow sustainable harvests for commercial and recreational purposes. Research into approaches to optimize the ecological, aesthetic, and economic values of alligators while maintaining public safety is needed.
3. Investigations on population biology: The presence of healthy alligator populations, and the availability of institutional and financial resources, have led to numerous investigations of alligator biology over many years. Although the American alligator is the most thoroughly studied of all crocodilians, we still know relatively little about its population dynamics in the wild. A better understanding of the population ecology of this species would not only benefit the management of alligators but other large crocodilian species as well. These investigations are facilitated and financed by the presence of management programmes such as cropping and ranching, and are currently underway in several states. For example, a recent long-term study on growth and reproductive lifespan demonstrated female alligators can nest for up to 46 years, and that alligators commonly live to 50 and can possibly over 70 years (Wilkinson et al. 2016).
4. Research on husbandry techniques: Because of the extensive commercial ranching and farming industry in the USA, the American alligator is a prime candidate for research on captive husbandry. Incubation and rearing techniques need to be improved to increase the efficiency of the alligator ranching industry. Extensive research on these topics is currently underway, particularly in Louisiana (Reigh and Williams 2016) and Florida.
5. Research on international market dynamics of alligator skin prices: The economic stability of state alligator management programmes is largely dependent on revenues generated from the sale of skins and meat from harvested alligators. Low skin prices over the past several years have constrained alligator farming, wild harvest, and nuisance control enterprises, jeopardizing the ability of states to maintain alligator management and conservation programmes at optimum levels. A better understanding of alligator skin production supply chains, as well as supply and demand dynamics. will help both government and private participants in alligator management to understand and adapt to changing economic conditions.