III. Physical Characteristics.
A. Size.
Adult males and females are equal in size.
1. Green sea turtles reach about 78 to 112 cm (31-44 in.) and 68 to 186 kg (150-410
lb.). The largest individual collected was 1.5 m (5 ft.) and 395 kg (871 lb.).
2. Black sea turtles reach about 59 to 117 cm (23-46 in.) and 42 to 126 kg (93-278
lb.).
3. The Kemp's ridley and olive ridley are the smallest species, and reach about 55 to
65 cm (22-30 in.) and 30 to 50 kg (66-110 lb.).
The leatherback turtle is the largest sea turtle species; the Kemp's
ridley is one of the smallest. Compare their sizes to the size of a human.
4. Loggerheads reach about 82 to 105 cm (32-41 in.) and 66 to 101 kg (146-223 lb.).
5. Hawksbills reach about 53 to 114 cm (21-45 in.) and 27 to 86 kg (60-190 lb.).
6. Flatbacks reach about 81 to 97 cm (32-38 in.) and 60 to 84 kg (132-185 lb.).
7. The leatherback is the largest of all living sea turtles. Mature leatherbacks reach
about 1.2 to 1.9 m (4-6 ft.) and 200 to 506 kg (441-1,116 lb.). The largest leatherback
recorded was 916 kg (2,019 lb.).
B. Body shape.
Sea turtles are characterized by a large, streamlined shell and nonretractile head and
limbs.
C. Coloration.
1. Depending on the species, sea turtles range in color. They may be olive-green,
yellow, greenish-brown, or black.
2. The green sea turtle gets its name from the color of its body fat.
D. Flippers.
1. A sea turtle cannot retract its limbs under its shell as a land turtle can.
2. Flippers are adapted for swimming. Sea
turtles are awkward and vulnerable on land.
3. Foreflippers are long and paddlelike.
a. Long digits are fused throughout the flipper.
b. Only one or two claws are present on each foreflipper.
c. A sea turtle swims with powerful winglike beats of its foreflippers.
4. Hind flippers serve as rudders, stabilizing and directing the animal as it swims.
The hind flippers of some species are quite dexterous in digging nests in the sand.
E. Head.
1. A sea turtle cannot retract its head under its shell as a land turtle can.
2. Sea turtles have large upper eyelids that provide protection for their eyes.
3. Sea turtles do not have an external ear opening.
4. Like other turtles, sea turtles lack teeth. Jaw shape varies among species. Each
species has a jaw shape adapted for its diet.
F. Shell.
1. The large, bony shell provides protection from predation and abrasion.
2. In all species except the leatherback, the shell is covered with a layer of horny
plates called scutes.
a. Scutes are firm but flexible, not brittle.
b. Scientists can identify sea turtle species by the number and pattern of scutes.
c. The leatherback turtle has a thick and oil-suffused skin, which is an excellent
insulator allowing this species to venture into colder waters.
3. The dorsal (top) side of the shell is called the carapace.
a. Depending on species, the adult carapace ranges in shape from oval to heart-shaped.
b. In all species except the leatherback, the bony shell is composed of broadened,
fused ribs, and the backbone is attached to the carapace.
In all species except the leatherback, the backbone is attached to the
carapace.
c. The leatherback's carapace is composed largely of cartilage raised into prominent
logitudinal ridges. A layer of thoursands of small dermal bones lies just below the
leathery skin.
4. The ventral (bottom) side of the shell is called the plastron.
G. Sexual dimorphism.
1. Male and female sea turtles do not differ externally until they approach maturity.
2. Adult males have longer, thicker tails, because the male reproductive organ is
housed in the base of the tail. In males, the tail may extend beyond the hind flippers.
3. On some species, the claws on the foreflippers of males are elongated and curved,
which may help in grasping the females' shells during mating.
Senses
| 
