AMERICAN ALLIGATOR Alligator mississippiensis

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AMERICAN ALLIGATORAlligator mississippiensis
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IDENTIFICATION

• One of the largest living reptiles
• Has a large rounded body with thick limbs
• Size
• Adult males avg. length 13-14 ft,
  occasionally up to 16 ft,
• weight 400
  500 pounds
• Adult females avg. length 8 10
  ft and weigh 160 230
• pounds
• Both sexes have armored body with a muscular
  flat tail
• Nostrils located on the upper end of snout for
  submerged breathing

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IDENTIFICATION

• ALLIGATOR
• Broad head blunt snout
• Lower teeth do not show with mouth closed
• Black in coloration
• Prefer fresh water

• CROCODILE
• Narrow head- long snout
• Lower teeth visible when mouth is closed
• Brown in coloration
• Prefer salt/brackish water

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Alligator mississippiensis                      
                                                  
 
Crocodylus acutus                               
                                         
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LIFE HISTORY

• Living Fossil from the Age of Reptiles
• Has survived for over 200 million years
• Market Hunting and Habitat Loss depleted them
  from most of their natural range (est. 10 million
  skins taken)
• 1967 placed on Endangered List

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LIFE HISTORY

• USFWS, State Agencies, and concerned stakeholders
  joined forces
• KEY TO RECOVERY multi-discipline management
  practices
• 1987 removed from Endangered List
• Today widely distributed and numerous
  throughout most of its natural range
• Listed as Threatened due to
• - American crocodile listed as Endangered
• - Listed on CITES Appendix II
• - IUCN Red List LRIc (low risk, least
  concern)

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RANGE POPULATION

• National population gt 1 million naturally
  occurring
• 150 active farming operations
• Natural Range Central America and Southern
  United States to include Alabama, Arkansas,
  North South Carolina, Florida, Georgia,
  Louisiana, Mississippi, Oklahoma, and Texas.

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ECOLOGY

• HABITAT
• - Primarily freshwater edges around
• swamps, marshes, rivers, lakes, and
  ponds.
• - Will venture into brackish or salt water
• for short periods, lacks the buccal (
  salt
• secreting gland) found in crocodiles.

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ECOLOGY

• FEEDING HABITS
• - Carnivorous, opportunistic feeder, will eat
  anything it
• can catch.
• - Hunts primarily in water will take small
  mammals at
• waters edge.
• - Eats small prey whole large prey is
  drowned
• (tenderized) then eaten in large pieces
• - Have a specialized valve (glottis) allows
  for catching prey
• underwater
• - Feeding activity ceases if water
  temperature falls
• below 20º to 23ºC (68-73ºF)

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ECOLOGY

• FEEDING HABITS
• - Preferred Foods
• Adult fish, turtles, wading birds,
  snakes,
• frogs, carrion, and small
  mammals.
• Juvenile small fish, crustaceans, snails,
• shrimp, tadpoles, and
  frogs.
• - Food for juveniles are preyed on by
  snakes,
• raccoons, wading birds,
  large fish,
• otters, osprey, and other
  alligators.
• - Consumption adults consume 20 lbs of meat
  per week
• in warm weather
  0 lbs during winter

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ECOLOGY

• BREEDING HABITS
• - Breed annually in April and May
• - Mating occurs in open waters at night
• - Males and females reach sexual maturity
• at 6 ft, in length (10-12 yrs of age)
• - Males roar to attract females and ward off
• other males
• - Mature males establish a territory and will
• service up to 10 or more females and will
• defend the territory against intruders

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ECOLOGY

• BREEDING HABITS
• - Once breeding occurs the female will seek
  out a secluded
• location and construct a large mound nest
  out of muddy
• vegetation
• - 1 wk later female lays 30-70 eggs
  (Jun-Jul)
• - 60-65 day incubation period
• - young hatch with aid of egg tooth
• - the young immediately signal mother with
  high pitched
• grunts

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ECOLOGY

• BREEDING HABITS
• - Mother will then open the nest and gently
• carry the young in her mouth to water
• - Females tend to their young up to 3 years
• - Young are born 6-9 inches long and have
• yellow bands for camoflage
• - Approx. 80 of the young fall to predation

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ECOLOGY

• PHYSICAL ADAPTATIONS
• --Large strong jaw has 80 teeth, and is
  used to
• capture, crush, and dismantle
• --Cannot chew must swallow food whole or
  in
• large chunks
• --Eyes, ears and nostrils are near top of
  head, with valves
• to close ears and nostrils when
  sumerged. This allows
• the alligator to be able to submerge
  its entire body and
• still breath
• --Can stay submerged 45-60 minutes
• --Toes are joined at base by webbing
• --Good binocular vision

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ECOLOGY

• LOCOMOTION
• -- Moves efficiently in water, swimming
• with serpentine movement of body and
• tail, uses hindfeet as rudders
• -- On land, slides on its belly, walks or
• gallops for short distances
• HEAT REGULATION
• -- Ectothermic
• -- Lies on the banks to bask in sun for
  warmth
• -- Submerges in heat of day to cool off

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ECOLOGY

• ENVIRONMENTAL ADAPTATIONS
• -Denning alligators create dens to survive
  the dry season
• and winters accomplished
  by digging tunnels
• into over hanging banks
• - Icing response Alligators can survive
  freezing
• conditions if they are in
  water, they submerge
• their bodiesbut keep their
  nostrils exposed.
• When the surface freezes they
  can still breathe.
• Essentially their upper body
  becomes trapped in
• ice. Testimony to their
  survival ability.

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TAXONOMY

• Kingdom Animalia
• Phylum Chordata
• Subphylum Vertbrata
• Class Reptilia
• Order Crocodilia
• Family Crocodylidae
• Subfamily Alligatorinae
• Genus Alligator
• Species alligator mississippiensis

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ECOSYSTEM ROLE

• KEYSTONE SPECIES
• -- Controls populations of prey species
• -- Creates peat beds (old or abandoned nest)
• providing for Red-bellied turtle
• (Chrysemys nelsoni) nesting sites
• -- 1 Value Gator Holes fill with water
  during
• rainy season and hold water well into the
  dry
• season creating miniature wetlands that
• provide critical habitat for a variety of
  species

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ECONOMIC ROLE

• NEGATIVE IMPACTS
• -- Threat to humans in highly populated
• areas have been known to eat pets and
• small children
• -- Nuisance alligator programs have been
• put into place with good success
• POSITIVE IMPACTS
• -- Tourism
• -- Hunting revenues hunted for skins and
  meat
• -- Multi-million dollar farming industry
  farmed
• for skins and meat

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FUTURE RESEARCH AND MANAGEMENT

• American alligator is the best studied species of
  crocodalian
• Research is currently being conducted by private,
  industrial, governmental, and educational
  institutions in the following areas population
  size, distribution and trends, animal sizes,
  sexes, activity periods, growth rates, and
  reproduction efforts, diet, nutritional
  energetics, responses to thermal effluent from
  reactors into cooling reservoirs, uptake of
  radionucleides, genetic patterns, and the
  conservation of the species.

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SAFETY NOTES

• 1) Dont feed the alligators
• 2) Keep your distance
• 3) Never disturb nest or small alligators
• 4) Keep your pets and children away from
  alligators
• 5) Dont swim in areas that are known alligator
  habitats
• 6) Be cautious when fishing in waters with
  alligators