Difference in Flipper Beating Frequency of Green Turtles in Water and on Land

Abstract

Sea turtles spend most of their lives in marine habitats, but they require a terrestrial environment for oviposition. In both conditions, they use limbs for thrust production. We attached animal-borne data loggers on green turtle and calculated the stroke frequency during swimming in water and crawling on land from surging acceleration. Stroke frequency was compared during swimming and crawling. The results showed that stroke frequency during terrestrial crawling is significantly higher than during swimming. This contrasts with previous studies of animals performing drag-based swimming. Because green turtles are considered to be lift-based swimmers that produce thrust mainly by dorsoventral excursion, one hypothesis is that anteroposterior excursion may be restricted despite its importance in terrestrial crawling and drag-based swimming. Small anteroposterior excursion resulting in short stride length may be complemented by higher stroke frequency during crawling.