SWIMMING AND DIVING IN YOUNG LOGGERHEAD SEA-TURTLES (CARETTA-CARETTA L)

Young loggerhead turtles (< 400 g body weight) employ a simultaneous double hindlimb kick for 95% of their swimming. The large foreflippers are folded against the carapace in this swimming mode. This type of swimming is progressively replaced by an alternate-limb action as the turtles grow beyond 400 g and is not seen in yearling animals (1,500 g). Synchronous forelimb movement is much less common in young Caretta than in green turtles, Chelonia mydas, of similar age. Hatchling loggerheads are positively buoyant and dive with difficulty. Diving improves as the animals grow and by the time a weight of 300-400 g is reached, animals will dive to a depth of more than 2 m. Despite their positive buoyancy, young loggerheads are capable of hovering over and browsing from, benthic food organisms.