Ethogram of the Nesting Female Loggerhead (Caretta caretta)

The nesting behavior of the loggerhead (Caretta caretta) was studied on a barrier beach island in Florida during June and July of several years. Ten phases of nesting involve about 50 distinct action patterns, not counting variants and similar patterns occurring in different phases. Some phases, such as digging of the egg chamber, involve highly stereotyped action patterns that occur in a rigidly fixed sequence of complex and intricate behavior. The switch from one phase to the next appears to be controlled by external stimuli except for the termination of egg laying, which sometimes involves depletion of the egg stores. Comparisons are made with earlier reports on the loggerhead and with the other species of sea turtles. We present evidence for a hypothesis that most of the action patterns of nesting are highly modified locomotor patterns that retain the basic coordination pattern of quadrupedal-gait walking (footfall pattern: left hind, left fore, right hind, right fore).