Diamondback terrapins drink rain straight from the sky
A diamondback terrapin lives where rivers meet the sea, in water too salty for most freshwater turtles. To get a fresh drink, it sips the thin layer of rainwater that floats on top of salt water after a storm, or simply tilts its head back and opens its mouth to catch the falling drops.
Terrapins occupy a thin ribbon of American tidal marsh on two coastlines, stretching from Cape Cod to the Florida Keys and around to Texas, plus an isolated population in Bermuda that got there without human help. The name comes from the Algonquian word torope, which early settlers used for turtles that lived neither in freshwater nor at sea. Their skin largely keeps salt out, and special tear glands can shed excess salt when they are dehydrated. Each has its own pattern of black wiggly markings, so no two look alike.
Females are much bigger than males and have heavier, more muscular jaws for crushing clams, snails and crabs. Where terrapins are numerous, their appetite for saltmarsh periwinkles may help protect cordgrass, which the snails can otherwise overgraze. Females can store sperm for years, so a single clutch may have several fathers, and nest temperature decides whether hatchlings become male or female. Clutches average about 5.8 eggs in southern Florida but 10.9 in New York. Hatchlings can survive freezing, which may help them spend winter on land.
Males mature in 2 to 3 years, while females take 6 to 7, or 8 to 10 in the northern subspecies. Wild terrapins typically live around 25 years, and captive ones up to 40. Because they leave the water only to nest, much of their behaviour remains poorly understood.
In the early 1900s terrapin was a prized delicacy, and hunting nearly wiped the species out. Today crab traps are a major threat, since terrapins go after the same bait; an estimated 14,000 to 15,000 drown in traps each year along the New Jersey coast alone. Boat propellers, raccoons raiding nests and seawalls that replace sandy nesting shores add to the pressure.
Source: Diamondback terrapin
