Fig. 4. Typical dives at (A) Big Razorback Island, with a gradual slope, and (B) Turks Head, with a steep slope. The x-axis is time, swimming speed is in red, and dive depth is in black; the black dots over the green lines represent strokes recorded as swaying acceleration, and the vertical dashed lines delineate the separation of the dive into three phases: descent, bottom and ascent. Swimming behavior is categorized as continuous stroking (black horizontal bar), stroke-and-glide swimming (grey horizontal bar) and prolonged gliding (open horizontal bar). Blue lines represent the body angle calculated from surging acceleration.