Common Snapping Turtle Growth

The common snapping turtle (Chelydra serpentina) is one of the largest freshwater turtles, and it lives in ponds, lakes or streams throughout North and South America. Easily recognizable due to large, beak-like jaws and a wide carapace or upper shell, common snapping turtles can be kept as household pets. Throughout their 40 to 50 year lifetime, turtles grow an average of 20 inches in diameter.

  1. Eggs and Hatchlings

    • Female snapping turtles lay 20 to 40 eggs in open sand or vegetation, and the eggs incubate for around 100 days. After incubation, the hatchlings emerge and hide in nearby water. Hatchling common snapping turtles are only an inch in length when they emerge, and the hatchlings are extremely susceptible to predation.

    Zero to Four Years

    • After hatchlings emerge and begin feeding on insects, small fish, crustaceans and other small animals, they gain diameter and weight. In the first four years of growth, snapping turtles will grow from one inch to six inches in diameter. Weight is more variable based on the time of year and the diet of the individual turtle, but on average young turtles weigh 10 to 15 pounds and have an average carapace diameter of one to 10 inches. Due to the long lifespan of the snapping turtle, growth is very slow and intermittent. Turtles enter hibernation in late autumn and do not emerge until spring, so growth stops during winter months.

    Four to Seven Years

    • Male common snapping turtles reach sexual maturity at five years, and females take an additional two years. Once turtles reach sexual maturity, growth slows significantly. At seven years, male and female turtles reach an average of 10 to 35 pounds and have an average carapace diameter of 10 to 18 inches.

    Maturity

    • Common snapping turtles can live 40 to 50 years in the wild. After sexual maturity, weight gain and carapace growth slow, so on average turtles remain the same weight and size after seven years. Exceptionally large snapping turtles exist, but individuals are rare and usually bred in captivity. Healthy mature snapping turtles weigh an average of 35 pounds and have a carapace diameter of 18 to 20 inches. Males tend to be slightly larger than females

    Growth in Captivity

    • If common snapping turtles are raised in captivity, their growth pattern is similar to in the wild. However, overfeeding and under-exercising can lead to obesity. Obese turtles are larger and heavier than healthy turtles, and can reach up to 70 pounds. Captive turtles do not live as long as wild turtles, but on average healthy captive turtles weigh 35 pounds and have a shell diameter of 18 inches, similar to wild turtles.