Alligator Snapping Turtle

The alligator snapping turtle (Macrochelys temminckii) is the largest freshwater turtle in the United States. This hulking, dinosaur-like turtle lurks along the bottom of waterways in the Midwest, Southeast, and some parts of the Southwest. It is a member of the Chelydridae family ofturtles, which includes the common snapping turtle of the order Chelydra. People often mistake the common snapping turtle for the alligator snapping turtle, but the alligator snapping turtle stands out due to its prehistoric appearance and massive size.

Threats:

Harvest, Poaching and Bycatch

Commercial harvesting in the late 1960s and 1970s caused a significant decline in alligator snapping turtle populations across its historic range. At one point, people harvested three to four tons of alligator snapping turtles per day from Flint River, Georgia. Commercial harvest of alligator snapping turtles is against the law in all states within its range. However, Mississippi and Louisiana allow recreational harvest with some restrictions.

Despite efforts to end commercial harvest, illegal harvest poses a threat to the species due to the global demand for pet turtles and turtle meat. In 2017, three men were convicted of illegally collecting 60 large alligator snapping turtles in a single year and transporting them across state lines in violation of the Lacey Act.

Alligator snapping turtles also face threats from incidental harm from fishing and recreational activities. They are at risk of,

• accidental capture
• swallowing fishhooks
• drowning when captured on trotlines and limb-lines (Trotlines are multiple hooks strung across a stream and limb lines are hooks hung from branches.)
• drowning from entanglement in fishing line
• suffering life-threatening injuries from boat propeller strike

Despite their decades-long lifespans, their chances of survival are low before they reach maturity. This makes their populations sensitive to the effects of harvest, especially that of adult females. Surveys conducted in Flint River 22 years after commercial harvest ended showed populations had not recovered.

Habitat Alteration

Both natural and human-caused changes to freshwater habitat in the alligator snapping turtle’s range pose challenges to the alligator snapping turtle’s survival. These include:

• Dredging, logging for submerged wood, erosion, changes in the near shore freshwater areas, climate change climate change
  Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.
  
  Learn more about climate change
• Run-off from farming and urban areas increases pollution in waterways.
• When water is no longer in an area, the turtles must move across dry land. There, they are less agile and more vulnerable to predators and humans. 

Nest Predators and Parasites

Although adult alligator snapping turtles do not have predators other than humans, their nests and young are vulnerable to natural predators.

• raccoons
• opossums
• bobcats
• river otters
• invasive red imported fire ants

The phorid fly (Megaselia scalaris) can infest alligator snapping turtle nests. The fly lays its eggs on the ground, and its larvae consume nearby organic material. Scientists have seen evidence of the phorid fly larvae damaging eggs and killing turtle hatchlings.The extent of the threat phorid flies pose on the species is unknown. 

Recovery Efforts

Tishomingo and Natchitoches National Fish Hatcheries raise alligator snapping turtles for release into the wild to restore and bolster populations. We have released them in: 

• Southern Illinois

• Oklahoma

• Louisiana

• Kansas