Lives lived at sea
            Humans hardly know these ancient creatures. What they know is that marine turtles belong to the order Chelonia, an order of reptiles that has existed and flourished since prehistory. Marizal Calpito and Lourdes P. Calacal of the Department of Environment and Natural Resources explain: ’’Some 200 million years ago, marine turtles developed as the earth throbbed with dramatic geophysical changes--surviving as the living conditions changed, adapting to the natural rhythms of prehistoric life. Down through the ages, they thrived, remaining much the same as their hardy ancestors.’’ Marine turtles can be differentiated from their terrestrial and freshwater relatives by their flattened forelimbs. Freshwater turtles have five claws on each forelimb with easily distinguishable individual digits. By comparison, marine turtles have flattened foreflippers with obscured individual digits. Marine turtles are air-breathing reptiles that live their long lives mostly at sea. But they spend a critically important part of their life in sandy beaches. Female marine turtles come ashore several times every two or three years to nest. Yet scientists know little about how they navigate, where they grow up, or how long they live. Why is it so difficult to study marine turtles?  "They’re a mystery,’’ said Dr. Archie Carr, a herpetologist, or a zoologist who studies reptiles and amphibians. Carr has been dubbed the ’’Father of Marine Turtle Research’’. Carr set up camp on the beach at Tortuguero, Costa Rica in 1954 to study the marine turtle. Several others have followed suit. But despite this explosion of researches, scientists are frustrated. ’’I don’t know any branch of science where we have applied so much effort and learned so little,’’ complained Dr. Richard Byles of the US Fish and Wildlife Service. 

Mating and courtship
            The reproduction life stage of the marine turtle is critical to conservation and management since it is during this period that they are most vulnerable to the adverse effects of human activities, said Calpito and Calacal in an article they wrote for Canopy International. The two cite the Green turtle as a case in point. Mating starts with courtship. ’’Green turtles’ courtship behavior is a highly charged activity punctuated by rivalry among courting males,’’ they wrote. ’’A male communicates his intentions to a female by caressing the female’s head and by raining her neck and rear flippers with gentle bites. The courted female may indicate her refusal by facing the male in vertical position, limbs widespread, as if emphatically declaring her rejection of the male. Or she may seek refuge in ’no male turtles allowed’ area or simply the areas that males apparently avoid.’’ If the female is receptive to the male, the male proceeds to embrace the female by anchoring his long front claws on the uppermost portion of the female’s carapace while his rear flippers secure the lower portion of his mate’s shell.