by Pat McShea
A cast of a large leatherback sea turtle now swims overhead near the microscope station in
Discovery Basecamp. In its suspended position, this reptile model provides a clear example of the principle known as counter shading.
The term refers to a common animal color pattern in which the top (dorsal side) is dark while
the underside (ventral side) is light.
While swimming or resting in the ocean the turtle’s counter shading helps to camouflage it
from both the prey it seeks and the predators it must avoid.
Viewed from below during the day, the creature’s light colored underside blends with light
saturated water. Viewed from above, its dark back offers little contrast with murky waters beneath it.
Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.