Snapping turtles are captivating reptiles native to North America, often found in freshwater environments. Their impressive size frequently leads to questions about how large they can become.
Common Snapping Turtle Dimensions
The common snapping turtle (Chelydra serpentina) is the more widespread of the two major snapping turtle species. Adults typically have a straight-line carapace length ranging from 25 to 47 centimeters (9.8 to 18.5 inches), though some may reach nearly 50 cm (20 inches). In terms of weight, common snapping turtles generally fall between 4.5 and 16 kilograms (9.9 to 35.3 pounds).
Male common snapping turtles tend to grow larger than females. The average breeding common snapping turtle has a carapace length of about 28.5 cm (11.2 inches) and weighs approximately 6 kg (13 pounds).
Alligator Snapping Turtle Dimensions
Alligator snapping turtles (Macrochelys temminckii) are significantly larger than common snapping turtles and are the largest freshwater turtles in North America. Adults typically have a carapace length between 35 and 80.8 centimeters (13.8 to 31.8 inches) and commonly weigh from 8.4 to 80 kilograms (19 to 176 pounds).
Males of this species are generally larger than females. They possess distinctive physical traits, including a large head, a hooked beak, and three prominent rows of spiked scutes along their carapace, which help distinguish them from common snapping turtles.
Influences on Growth
Several biological and environmental elements shape the ultimate size a snapping turtle achieves. Age is a primary factor, as both common and alligator snapping turtles exhibit indeterminate growth, meaning they continue to grow throughout their lives, albeit at a slowing rate after reaching maturity.
Diet and food availability also play a substantial role. A consistent supply of nutrient-rich food allows for more robust growth. Snapping turtles are opportunistic omnivores, consuming various aquatic invertebrates, fish, amphibians, and even some plant matter.
Habitat quality, encompassing factors such as water temperature, space, and overall environmental conditions, also impacts growth rates. Warmer temperatures can increase metabolic rates, potentially accelerating growth. Lastly, genetics determine an individual turtle’s inherent potential for maximum size.
Exceptional Cases and Longevity
While average sizes provide a general understanding, some snapping turtles grow to truly exceptional dimensions. For common snapping turtles, weights exceeding 16 kg (35.3 pounds) are considered unusual, though wild specimens up to 34 kg (75 pounds) have been reported. Captive common snapping turtles, often due to overfeeding, have reached weights as high as 39 kg (86 pounds). One notable common snapping turtle, named “Big Snap Daddy,” reportedly weighed 98 pounds and was estimated to be over 90 years old.
Alligator snapping turtles hold the records for the largest verified sizes among snapping turtles. A documented individual at the Shedd Aquarium reportedly weighed 113 kg (249 pounds). Another large specimen was noted at 107 kg (236 pounds) at the Brookfield Zoo. Unverified claims suggest even larger individuals, with one from Kansas in 1937 rumored to weigh 183 kg (403 pounds). The ability of these turtles to reach such impressive sizes is closely linked to their long lifespans, as they can live for many decades, allowing for continuous growth over an extended period.