Earthsky Interviews
Private: American Alligator
05-13-2002 - Biodiversity
_DB:_ This alligator is North America’s largest – and most vocal – reptile. That’s its bellow you’re hearing – alligators also grumble and hiss.
_JB:_ But more often they don’t make any noise while lurking at the water’s surface, stalking their prey. These silent hunters – alligators – have themselves been hunted for generations – both for their hides and for sport. By the late 1960s, alligator populations had dwindled so much that the alligator was declared an endangered species. The good news is that – thanks mainly to conservation and harvesting programs – alligators are making a comeback. And that means, in some areas where with burgeoning human populations are encrouching on alligator habitats – there’ve been more alligator attacks on people and their pets.
_DB:_ Conservationists say it’s important to protect alligators, though – because their survival is directly linked to the survival of other creatures in the wetlands ecosystem. For example, the Florida red-bellied turtle incubates its eggs in alligator nests. Alligators also control prey species. And the deep water-filled holes that alligators dig – called “gator holes” – support a whole community of other creatures and plants.
_JB:_ Thanks today to the “National Fish and Wildlife Foundation”:http://www.nfwf.org/ and to the “U.S. Forest Service”:http://www.fs.fed.us/. We’re Block and Byrd for Earth and Sky.
The following individuals were interviewed for today’s show. Our thanks to:
F. Wayne King, PhD
Curator of Herpetology
Florida Museum of Natural History
H. Franklin Percival, PhD
Florida Cooperative Fish and Wildlife Research Unit
Professor of Wildlife Ecology and Conservation
University of Florida
Alligator websites:
“American Alligator”:http://enature.com/ads/popup/mem_pop_up.asp – eNature.com
The Wild Ones Animal Index – “The American Alligator”:http://www.thewildones.org/Animals/gator.html
“Crocodilians: Natural History and Conservation”:http://www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/cnhc.html (University of Florida)
University of Florida/IFAS Agrigator – “American Alligator”:http://www.ifas.ufl.edu/AgriGator/gators/
Author’s Notes:
The alligator is an ancient species – but today, only two species of alligator exist – the Chinese alligator and the American alligator. The gentler, smaller Chinese alligator lives in China’s Yangtze River Basin.
(Spanish el lagarto,”the lizard”), common name for two carnivorous reptiles in the crocodilian order.
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.
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.
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 They can tolerate a reasonable degree of salinity for short periods of time, being occasionally found in brackish water around mangrove swamps, although they lack the buccal salt-secreting glands present in crocodiles.