Home › Volumes › Reptiles › Turtles and Tortoises
Diamond-back Terrapin
Colouration.—The carapace is grayish or olive, sometimes with darker concentric markings which appeal to the arrangement of the grooves. The lower border of the carapace is olive, each plate embracing hollow black squares or blotches. The plastron is deep yellow, with numerous black dots in rows and dusky bands extending crosswise.
Dimensions.—The present species is the smallest of the genus. The maximum size is ten inches, and this is considerably above the average, which is about eight inches. Specimens of the latter size are now becoming rare.
Distribution.—Salt marshes of the Atlantic Coast and southern borders of the Gulf States, from Massachusetts to Texas.
Habits.—In its habit of persistently selecting salt and brackish waters, this species differs from the other terrapin. It occurs principally in the salt marshes along the coast, but not a few specimens are found well up the rivers, though always within tide line. On the Hudson the writer has taken them as far north as Newburgh.
Distribution.—Eastern States.
Distribution.—New York, New Jersey, and Pennsylvania.
Distribution.—Pacific Region.
Distribution.—Eastern States.
The species differs from all the others of its genus in the rough character of the carapace. Each of the shields contains a number of concentric grooves, rising in step-like fashion. It is owing to the angular, and concentric areas embraced by the shields that the popular name--"diamond-back"--has originated. A well-defined keel is represented by a blunt ridge, rising within each of the central shields; the highest of these ridges is in the central or middle shield of the back. Examined from the side, the keel appears as a series of serrations.
With very young specimens the upper shell is almost white, with black, concentric markings.
The head markings of the adult are strong and constant. There are no stripes. The head, neck and all the exposed, fleshy parts are slaty gray, profusely covered with rounded, black dots.
Following are the measurements of a specimen now considered in the markets to be of fair size, and selling for about $6 each:
Length of Carapace . . . . . 7 1/2 inches.
Width of Carapace . . . . . 5 1/2 inches.
Length of Plastron . . . . . 6 1/2 inches.
Width, Flat Portion, of Plastron . . . . . 3 1/2 inches.
Weight . . . . . 2 pounds.
For every half an inch over these measurements, the market prices soar upward substantially. A specimen slightly over eight inches in length, from the same lot as the specimen measured was marked at $8. The man selling these turtles informed the writer that the prices for specimens over seven inches in length might actually be said to increase $1 for every additional half an inch in length. Specimens under 6 inches are of but slight value in the markets. A turtle about five inches in length will sell for about $1.50. Every year these turtles are becoming scarcer and the prices higher.
The species does not live long in captivity unless provided with salt water. Kept in fresh water its skin becomes infected with fungus which soon kills the reptile. If provided with a tank containing artificial "sea-water" it seems hardy enough and lives for an indefinite period. The water may be prepared by adding common salt until it yields a brackish taste. Chopped clams and oysters are foods of captive specimens, though they will also take small fish and raw meat. They are also fond of the small "periwinkle" snails so common on the mud flats exposed by the shore tides and the writer has observed a wild specimen voraciously eating a small "fiddler" crab. As the jaws are very powerful they have no trouble in crushing the shells of such creatures. Judging from the tendency of captive specimens to nibble at lettuce leaves that are thrown into their tank, wild individuals undoubtedly feed in part upon the various species of sea-weed. Like the other terrapin the species always takes its food under water.
Owing to the very broad, extensively webbed hind feet this turtle is perfectly at home in the water and has a habit of floating with just the tip of its snout above the surface, the shell being kept in a perpendicular position by a slow, treading motion of the hind feet.
Although this species ranges well into the North, it is more abundant and attains a larger size in warmer waters. It occurs most commonly in those numerous indentations of the Atlantic coast from the Chesapeake, to Savannah, Georgia. Its great favour as an article of diet threatens its ultimate extinction.
The Genus Chelopus: The small species of this genus are fairly aquatic, though not to such an extent as the larger terrapin. One species evinces a decided inclination toward terrestrial habits, though it is seldom found away from damp areas. Three of the species inhabit the Eastern states and one, the Pacific Region.