Natural History of the Ornate Box Turtle, Terrapene ornata ornata AgassizLegler, John M.
Science
Natural History of the Ornate Box Turtle, Terrapene ornata ornata Agassiz
Legler, John M.
Ornate box turtle
Fractures of the limb bones are common. A female from Stafford County,
Kansas (Pl. 29, Fig. 4), showed a typical case of fracture and
subsequent repair; the right fibula had been broken and the ends
dislocated; a great mass of bone joined the repaired break to the
middle of the tibia, giving the entire skeleton of the leg the
appearance of the letter "H." The fibula, shortened by the
dislocation, no longer articulated by its proximal end with the femur;
the tibia probably bore the entire load in the period of repair and
the transverse connection that formed between the bones later took
over the function of the fibula.
There is little doubt that ornate box turtles are stepped on or
trampled by cattle, at least occasionally, but I never observed such
an incident; the predilection of ornate turtles for dung insects and
for moving along cattle pathways brings them to close quarters with
cattle and probably did likewise with native ungulates. A steer,
stepping on a box turtle, could inflict superficial damage to the
shell or cause broken limbs but would probably not crush the turtle
unless on a hard substrate.
REPAIR OF INJURIES TO THE SHELL
Most adults and a few juveniles examined in the field and laboratory
had one or more small injuries on the carapace that had healed or were
undergoing repair. Such injuries almost never occurred on the
plastron. In an injury that was undergoing repair, a small piece of
smooth, whitened bone was exposed where a piece of epidermis was
missing from the shell. One or more edges of the exposed bone
characteristically projected over the surrounding epidermis, making
the bone appear as though it had been driven forcefully, like a
splinter, into the shell (Pl. 29, Figs. 1 and 2). Because of their
curious appearance, small areas of repair were referred to in my notes
as "splinter scars." The position and number of splinter scars were
often recorded as supplementary means of individualizing turtles in
the field.
Splinter scars result from minor abrasions that damage a few square
millimeters of the shell. Larger areas of exposed bone were noted in
only a few specimens. Two turtles at the Damm Farm had bone exposed on
more than one-half the surface area of the carapace; both of these
turtles were probably burned in the grass fire of 1955. Ordinarily, a
break in the shell does not induce extensive regeneration of tissues;
when shells are damaged by crushing or cracking, regeneration of
epidermis and bone occurs only along the lines of fracture, unless the
broken parts have been dislocated. Ligamentous tissue develops in some
breaks on the plastron, the broken area remaining slightly movable
after healing is completed (Pl. 24).
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