Estimates for ASM ranged from 12.0 to 23.0 years (mean: 16.3 ± 0.53 SE), SSM ranged from 76.1 to 94.0 cm CCL (mean: 84.9 ± 0.90 SE), and maximum observed reproductive longevity was 31 years for a 45-year old male flatback. We identified the onset of sexual maturity for 29 turtles, based on rapprochement growth patterns in the bones. We analyzed humeri from 74 flatback sea turtles ranging in body size from 6.0–96.0 cm curved carapace length (CCL), and recovered from Western Australia (n = 48), Eastern Australia (n = 13), central Australia (n = 8 Northern Territory n = 3, the Gulf of Carpentaria n = 5), and unknown locations (n = 5). Using a rare collection of bone samples gathered from across northern Australia, we applied skeletochronology and characterized the length-at-age relationship, established baseline growth rates from the hatchling to adult life stages, and produced empirical estimates of age-at- and size-at-sexual-maturation (ASM, SSM). Because of this danger, many beachfront communities have adopted lighting ordinances requiring lights to be shut off or shielded during the nesting and hatching season.To address a major knowledge gap for flatback sea turtles (Natator depressus), a species endemic to Australia and considered ‘Data Deficient’ for IUCN Red List assessment, we present the first-ever skeletochronology-derived age and growth rate estimates for this species. After their first frantic crawl from the nest to the ocean, male sea turtles never return to the shore again, and females come back only long enough to lay eggs.Īrtificial lights on beachfront buildings and roadways-often called light pollution-can distract hatchlings on their way to the ocean. This usually occurs at night, and the hatchlings use the bright, open view of the night sky over the water to find their way to the sea. Hatchlings range from 1.5 to 3 inches (3.8 to 7.6 centimeters) in size, depending on the species, and emerge from the nest as a group. For this reason, conservationists and wildlife managers leave turtle eggs in their original location whenever possible so that sex ratios are determined naturally.Īfter incubating for about two months, the eggs begin to hatch. Warmer temperatures produce more females, whereas cooler temperatures result in more males. Nesting turtles may come to shore several times in a nesting season to repeat the process.Īs is true for some other reptiles, the temperature of the sea turtle nest determines the sex of the hatchlings. When egg-laying is complete, the turtle covers the eggs, camouflages the nest site, and returns to the ocean. She uses her rear flippers to dig the nest hole, then deposits 80 to 150 eggs that look a lot like Ping-Pong balls. In summer, an ancient reproductive ritual begins when the female leaves the sea and crawls ashore to dig a nest in the sand. Mating occurs roughly every two to three years in shallow waters. Most sea turtles grow slowly and have a lifespan of many decades. Leatherbacks are the biggest and can grow to 2,000 pounds (900 kilograms). The smallest of the sea turtles are the two species of ridleys, weighing in at 85 to 100 pounds (38 to 45 kilograms) as adults. Unlike their terrestrial relatives, they cannot retract their heads into their shells. In most sea turtles, the top shell-or carapace-is composed of many bones covered with horny scales, or scutes. Sea turtles are among the oldest creatures on Earth and have remained essentially unchanged for 110 million years. There are seven species of sea turtle: the green sea turtle, Hawksbill sea turtle, loggerhead sea turtle, olive ridley sea turtle, Kemp’s ridley sea turtle, leatherback sea turtle, and flatback sea turtle. Although sea turtles can remain submerged for hours at a time while resting or sleeping, they typically surface several times each hour to breathe. These front flippers are long, narrow, and winglike, while their hind flippers are shorter. Their hydrodynamic shape, large size, and powerful front flippers allow them to dive to great depths and swim long distances. Sea turtles are reptiles remarkably suited to life in the sea.
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