Fig. 1
From: Head-mounted accelerometry accurately detects prey capture in California sea lions
Diagnostic signal phrase for detecting prey capture in California sea lions. Prey capture is detected from (A) a peak in heave axis smoothed Jerk data surpassing a threshold (‘Jerk threshold’) determined from sampling rate (shown in Fig. 2), resulting from a dorsal head tilt as the jaw opens; B a deceleration in estimated dynamic surge axis data surpassing −0.7 g (‘Deceleration threshold’) within 0.2 s of the end of A, as the head retracts during suction or pierce feeding; and C a surge axis estimated dynamic acceleration surpassing 1.0 g (‘Acceleration threshold’) within 0.5 s of B, as the mouth closes and head rocks ventrally. The detected event duration and integrals of heave axis smoothed Jerk and surge axis estimated dynamic acceleration, which were evaluated for their relationships with prey length, are shown here graphically