Snapping turtles are the largest freshwater turtles in North America. Just because they are small when you first adopt them does not mean they'll stay that way. Many snappers can reach up to 60 pounds when they're full grown. Read more here about how big they get. When snapping turtles are just babies, they will likely be about 2 inches in length, but they will grow quite quickly, and can reach a size of about 12-18 inches. Snapping turtles need special care to begin with, but their care is especially important when they're young. The kind of care they receive as babies will determine how healthy and big they will be when they reach maturity.