Michigan Alligators

Identification

The American alligator (Alligator mississippiensis) is one of 22 crocodilian species worldwide. The other native crocodilian is the American crocodile (Crocodylus acutus). The American alligator is distinguished from the American crocodile and caiman by its more rounded snout and black and yellow-white coloration. American crocodiles and caimans are olive-brown in color and have more pointed snouts. American alligators and crocodiles are similar in physical size, whereas caimans are 40% smaller.

Range and Habitat
The American alligator is found in wetlands throughout the coastal plain of the southeastern United States. Viable alligator populations are found in Texas, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama, Florida, Georgia, South Carolina and North Carolina. They can be found in almost any type of fresh water, but population densities are greatest in wetlands with an abundant food supply and adjacent marsh habitat for nesting.

The northern range is limited by low winter temperatures. Alligators are rarely found south of the Rio Grande drainage. They prefer fresh water but also inhabit brackish water and occasionally venture into salt water.

Fun Facts

Alligators are ectothermic — they rely on external sources of heat to maintain body temperature. They are most active at warmer temperatures, stop feeding when ambient temperature drops below 70o F (21o C) and become dormant below 55o F (13o C).

Alligators are among the largest animals in North America. Males can attain a size of more than 14 feet (4.3 m) and 1,000 pounds (473 kg). Females can exceed 10 feet (3.1 m) and 250 pounds (116 kg).

Alligators begin courtship in April throughout most of their range and breed in late May and early June. Females lay a single clutch of 30 to 50 eggs in a mound of vegetation from early June to mid-July. Nests average about 2 feet (0.6 m) in height and 5 feet (1.5 m) in diameter. Nests are constructed of the predominant surrounding vegetation, which is commonly cordgrass (Spartina spp.), sawgrass (Cladium jamaicense), cattail (Typha spp.), giant reed (Phragmytes spp.), other marsh grasses, peat, pine needles, and/or soil. Females tend their nests and sometimes defend them against intruders, including humans. Eggs normally take 65 days to complete incubation. In late August to early September, 9 to 10-inch (23 to 25-cm) hatchlings are liberated from the nest by the female. She may defend her hatchlings against intruders and stay with them for up to 1 year, but gradually loses her affinity for them as the next breeding season approaches.

Alligators are not normally aggressive toward humans, but can and will occasionally attack humans and cause serious injury or death. Most attacks are characterized by a single bite and release with resulting puncture wounds. Single bites are usually made by smaller alligators (less than 8 feet [2.4 m]) and result in an immediate release, possibly because they were unsure of their intended prey. One-third of the attacks, however, involve repeated bites, major injury, and sometimes death, normally made by alligators greater than 8 feet in length and are most likely the result of chase and feeding behavior.

In most serious alligator attacks, victims were unaware of the alligator prior to the attack. Female alligators frequently defend their nest and young, but there have been no confirmed reports of humans being bitten by protective females. Brooding females typically try to intimidate intruders by displaying and hissing before attacking.

Alligators quickly become conditioned to humans, especially when food is involved. Habitually feeding  alligators cause them to lose their fear of humans and can be dangerous to unsuspecting humans, especially children. Many aggressive or “fearless” alligators have to be removed each year following feeding by humans. Ponds and waterways at golf courses and high-density housing create a similar problem when alligators become accustomed to living near people.

Myths

Alligators have not been known to break the legs of full-grown men with their tails.

Damage Identification

Damage by alligators is usually limited to injuries or death to humans or domestic animals. Most alligator bites occur in Florida.

Alligators inflict damage with their sharp, cone-shaped teeth and powerful jaws. Bites are characterized by puncture wounds and/or torn flesh. Alligators prefer to seize an appendage and twist it off by spinning. Many serious injuries have involved badly damaged and broken arms on humans and legs on animals. Sometimes alligators bite or eat previously drowned persons. Coroners can usually determine whether a person drowned before or after being bitten.

Alligators sometimes excavate extensive burrows or dens to take refuge from cold temperatures, drought, and predators (other alligators and humans).

Legal Status

The American alligator is federally classified as “threatened due to similarity of appearance” to other endangered and threatened crocodilians. This provides federal protection for alligators but allows state-approved management and control programs. Alligators can be legally taken only by individuals with proper licenses or permits. Florida, Louisiana, Georgia, South Carolina and Texas have problem or nuisance alligator control programs that allow permitted hunters to kill or facilitate the removal of nuisance alligators. Other states call state wildlife officials to remove problem animals.

Damage Prevention and Control Methods

Exclusion
Bulkheads along edges of lakes and waterways. Wire mesh fences.

Habitat Modification
Minimize emergent vegetation. Drain ponds and borrow pits where appropriate and permitted.

Frightening
Prodding or other harassment can increase wariness. Hunting pressure increases wariness and avoidance of people.

Repellents
None are registered.

Toxicants
None are registered.

Fumigants
None are registered.

Trapping
Baited hooks and trip-snare traps are most effective.

ACKNOWLEDGEMENTS
The above information was adapted from PREVENTION AND CONTROL OF WILDLIFE DAMAGE with permission of the editors, Scott E. Hygnstrom, Robert M. Timm, and Gary E. Larson (Cooperative Extension Division, Institute of Agriculture and Natural Resources University of Nebraska-Lincoln, United States Department of Agriculture Animal and Plant Health Inspection Service, Animal Damage Control, Great Plains Agricultural Council Wildlife Committee).