FWS Focus

Overview

Characteristics
Overview

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

Scientific Name

Macrochelys temminckii
Common Name
Alligator Snapping Turtle
Western Alligator Snapping Turtle
FWS Category
Reptiles
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Physical Characteristics

Characteristics
Color & Pattern

They are deep brown and often have algae growth, which aids in their camouflage.

Size & Shape

Alligator snapping turtles are the largest freshwater turtle species in the United States. Adult males can reach lengths of up to 29 inches and weigh up to 249 pounds. Adult females can reach lengths of up to 22 inches and weigh up to 62 pounds.

Their shells have three rows of spikes giving them a prehistoric appearance. They have a long tail and muscular legs with webbed toes and long, pointed claws. Pointed, fleshy projections surround their eyes on the sides of their huge heads.

Characteristic category

Life Cycle

Characteristics
Life Span

The oldest snapping turtle documented in captivity was 80 years old but may live longer in the wild.  

Reproduction

The species does not reach sexual maturity until 11 to 21 years. A mature female produces only one clutch each year, ranging from eight to 52 eggs.

Characteristic category

Food

Characteristics
Food

Alligator snapping turtles consume a variety of foods. They feed on:

  • fish
  • crayfish
  • mollusks
  • smaller turtles
  • insects
  • nutria
  • snakes
  • birds
  • some vegetation
Characteristic category

Habitat

Characteristics
Habitat
  • Preferred Habitats:
    • Large rivers (deeper water)
    • Streams, canals, lakes, swamps
  • Favored Features:
    • High canopy forest areas
    • Structures like tree root masses, stumps, submerged trees
  • Seasonal Preferences:
    • Winter: Shallow areas
    • Summer: Deeper areas
  • Hatchlings:
    • Shallow water
    • Abundant canopy and vegetation

River or Stream

A natural body of running water.

Characteristic category

Behavior

Characteristics
Behavior

The alligator snapping turtle is the only turtle species that has a part of their body for luring prey. The lure is a small worm-like part of their tongue. This is how it works:

  1. The turtle will lay motionless.
  2. It will open its jaws slowly in a process that takes one to two minutes.
  3. The turtle will wriggle the lure on its tongue to attract the prey into striking distance.
  4. When the prey moves into the turtle’s mouth, its jaws will snap shut on the prey holding it there before it begins swallowing.

Geography

Characteristics
Range

Historic Range:

  • 14 states: Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Missouri, Mississippi, Oklahoma, Tennessee, and Texas.

Current Range:

  • 12 states: Alabama, Arkansas, Florida, Georgia, Illinois, Kentucky, Louisiana, Missouri, Mississippi, Oklahoma, Tennessee, and Texas.
  • The turtles are extremely rare in Kansas and Indiana and may be locally extinct in these areas.

Launch Interactive Map

Timeline

Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.

11 Items

Listing

Listing

Listing

Listing

Listing

Listing

Listing

Listing

4d

Listing

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Listing

Dec 30, 1982

Dec 30, 1982 Listing
Review of Vertebrate Wildlife for Listing as End. or Thr. Species
  • Publication type: CNOR
Item 1

Listing

Jun 14, 1983

Jun 14, 1983 Listing (Substantial)
Findings on Certain Petitions; 48 FR 27273-27274
  • Publication type: 90 day petition finding
Item 2

Listing

Feb 29, 1984

Feb 29, 1984 Listing (Not Warranted)
Finding on Petition to List Alligator Snapping Turtle as Thr. Species; 49 FR 7416-7417
  • Publication type: 12m petition finding
Item 3

Listing

Sep 18, 1985

Sep 18, 1985 Listing
Review of Vertebrate Wildlife; Notice of Review; 50 FR 37958-37967
  • Publication type: CNOR
Item 4

Listing

Jan 6, 1989

Jan 6, 1989 Listing
ETWP; Animal Notice of Review; 54 FR 554 579
  • Publication type: CNOR
Item 5

Listing

Nov 21, 1991

Nov 21, 1991 Listing
ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species; 56 FR 58804 58836
  • Publication type: CNOR
Item 6

Listing

Nov 15, 1994

Nov 15, 1994 Listing
ETWP; Animal Candidate Review for Listing as Endangered or Threatened Species.
  • Publication type: CNOR
Item 7

Listing

Jul 1, 2015

Jul 1, 2015 Listing (Substantial)
90-Day Findings on 31 Petitions
  • Publication type: 90 day petition finding
Item 8

4d

Nov 9, 2021

Nov 9, 2021 4d
Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for…
  • Publication type: Proposed
Item 9

Listing

Nov 9, 2021

Nov 9, 2021 Listing (Threatened)
Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for…
  • Publication type: Proposed
Item 10

Listing

Nov 9, 2021

Nov 9, 2021 Listing (Warranted)
Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for…
  • Publication type: 12m petition finding
Item 11