This species is unique in being able to use its tongue as a lure to entice fish into its mouth. The alligator snapping turtle feeds mainly on fish, but will also capture and eat small turtles. Alligator snapping turtles are sexually mature between 11 and 13 years of age. Courtship probably begins in late spring. Females lay 16 to 56 eggs during May and June.
Eggs are round, white and hard-shelled.
Hatching probably occurs in late summer. Females may produce eggs only every other year. The alligator snapping turtle seldom comes out of the water to bask in the sun. Females will leave the water to find an egg-laying site. Most of their time is spent in deep water in mud and hiding among root snags.