The Sea Turtle got lost in the Great Barrier reef after finding its destination (after travelling 24.276km). Now it's been replaced by the green racer. I'm racing against BLUE, RED YELLOW and WHITE.
Please drop me ASAP in the next cache. Don't wanna drop me within two weeks, than leave me in the cache!
Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.
The Sea turtles have a world-wide distribution; sea turtles can be found in all oceans except for the polar regions. Some species travel between oceans. The flatback sea turtle is found solely on the northern coast of Australia.
Biology
Sea turtles are almost always submerged in water, and, therefore, have developed an anaerobic system of respiration. Although all sea turtles breathe air, under dire circumstances they may divert to anaerobic respiration for long periods of time. When surfacing to breathe, a sea turtle can quickly refill its lungs with a single explosive exhalation and rapid inhalation. Their large lungs have adapted to permit rapid exchange of oxygen and to avoid trapping gases during deep dives. However, sea turtles must emerge while breeding, given the extra level of activity.
Life history
According to SeaWorld Parks & Entertainment, a lifespan of 80 years is feasible for sea turtles. It takes decades for sea turtles to reach sexual maturity. After mating at sea, adult female sea turtles return to land to nest at night. Different species of sea turtles exhibit various levels of philopatry. In the extreme case, females return to the beach where they hatched. This can take place every two to four years in maturity. They make from one to eight nests per season.
The mature nesting female hauls herself onto the beach, nearly always at night, and finds suitable sand on which to create a nest. Using her hind flippers, she digs a circular hole 40 to 50 centimetres (16 to 20 in) deep. After the hole is dug, the female then starts filling the nest with a clutch of soft-shelled eggs one by one until she has deposited around 50 to 200 eggs, depending on the species. Some species have been reported to lay 250 eggs, such as the hawksbill. After laying, she re-fills the nest with sand, re-sculpting and smoothing the surface until it is relatively undetectable visually. The whole process takes thirty to sixty minutes. She then returns to the ocean, leaving the eggs untended.
The hatchling's gender depends on the sand temperature. Lighter sands maintain higher temperatures, which decreases incubation time and results in more female hatchlings.
Incubation takes about two months. The eggs in one nest hatch together over a very short period of time. When ready, hatchlings tear their shells apart with their snout and dig through the sand. Again, this usually takes place at night, when predators such as seagulls cannot fly. Once they reach the surface, they instinctively head towards the sea. If, as happens on rare occasions, hatching takes place during daylight, only a very small proportion of each hatch (usually 0.01%) succeed, because local opportunist predators, such as the common seagull, gorge on the new sea turtles. Thus there is an obvious evolutionary drive to hatch at night, when survival rates on the beach are much higher.
The hatchlings then proceed into the ocean, where a variety of marine predators await them. In 1987, Carr discovered that the young of Chelonia mydas and Caretta caretta spent a great deal of their pelagic lives in floating sargassum beds, where there are thick mats of unanchored seaweed. Within these beds, they found ample shelter and food. In the absence of sargassum beds, sea turtle young feed in the vicinity of upwelling "fronts". In 2007, Reich determined that green sea turtle hatchlings spend the first three to five years of their lives in pelagic waters. In the open ocean, pre-juveniles of this particular species were found to feed on zooplankton and smaller nekton before they are recruited into inshore seagrass meadows as obligate herbivores.[4][5]
Instead of nesting individually like the other species, Ridley sea turtles come ashore en masse, known as an "arribada" (arrival). With the Kemp's ridley sea turtles this occurs during the day
Conservation
All species of sea turtles are listed as threatened or endangered. The leatherback, Kemp's Ridley, and hawksbill sea turtles are critically endangered. The Olive Ridley and green sea turtles are endangered, and the loggerhead is threatened. The flatback's conservation status is unclear due to lack of data.
One of the most significant threats now comes from bycatch due to imprecise fishing methods. Long-lining has been identified as a major cause of accidental sea turtle death. There is also black-market demand for tortoiseshell for both decoration and supposed health benefits.
Sea turtles must surface to breathe. Caught in a fisherman's net, they are unable to surface and thus suffocate. In early 2007, almost a thousand sea turtles were killed inadvertently in the Bay of Bengal over the course of a few months after netting.
However, some relatively inexpensive changes to fishing techniques, such as slightly larger hooks and traps from which sea turtles can escape, can dramatically cut the mortality rate. Turtle Excluder Devices (TEDs) have reduced sea turtle bycatch in shrimp nets by 97 percent. Another danger comes from marine debris, especially from abandoned fishing nets in which they can become entangled.
Beach development is another area which threatens sea turtles. Since many sea turtles return to the same beach each time to nest, development can disrupt the cycle. There has been a movement to protect these areas, in some cases by special police. In some areas, such as the east coast of Florida, conservationists dig up sea turtle eggs and relocate them to fenced nurseries to protect them from beach traffic.
Since hatchlings find their way to the ocean by crawling towards the brightest horizon, they can become disoriented on developed stretches of coastline. Lighting restrictions can prevent lights from shining on the beach and confusing hatchlings. Sea turtle-safe lighting uses red or amber LED light, invisible to sea turtles, in place of white light.
Another major threat to sea turtles is black-market trade in eggs and meat. This is a problem throughout the world, but especially a concern in the Philippines, India, Indonesia and the coastal nations of Latin America. Estimates reach as high as 35,000 sea turtles killed a year in Mexico and the same number in Nicaragua. Conservationists in Mexico and the United States have launched "Don't Eat Sea Turtle" campaigns in order to reduce this trade in sea turtle products. These campaigns have involved figures such as Dorismar, Los Tigres del Norte and Maná. Sea turtles are often consumed during the Catholic season of Lent, even though they are reptiles, not fish. Consequently, conservation organizations have written letters to the Pope asking that he declare sea turtles meat.
Climate change may also cause a threat to sea turtles. Since sand temperature at nesting beaches defines the sex of a sea turtle while developing in the egg, there is concern that rising temperatures may produce too many females. However, more research is needed to understand how climate change might affect sea turtle gender distribution and what other possible threats it may pose.
Sea turtles are very vulnerable to oil pollution, both because of their tendency to linger on the water's surface, and because oil can effect them at every stage of their life cycle.[36] Oil can poison the sea turtles upon entering their digestive system,
Fragile ecosystems
Sea turtles play key roles in two ecosystem types that are critical to them as well as to humans—oceans and beaches/dunes. In the oceans, for example, sea turtles, especially green sea turtles, are one of very few creatures (manatees are another) that eat the sea grass that grows on the sea floor. Sea grass must be kept short to remain healthy, and beds of healthy sea grass are essential breeding and development areas for many species of fish and other marine life. A decline or loss of sea grass beds would damage these populations, triggering a chain reaction and negatively impacting marine and human life.
Beaches and dunes form a fragile ecosystem that depends on vegetation to protect against erosion. Eggs, hatched or unhatched, and hatchlings that fail to make it into the ocean are nutrient sources for dune vegetation[citation needed]. Every year, sea turtles lay countless eggs on beaches. Along one twenty-mile (32 km) stretch of beach in Florida alone, for example, more than 150,000 pounds of eggs are laid each year.
Threats to sea turtles
Of the seven species of sea turtles, all are listed on the IUCN Red List of Endangered Species as either "endangered" or "critically endangered". Although sea turtles usually lay around one hundred eggs at a time, on average only one of the eggs from the nest will survive to adulthood. While many of the things that endanger these hatchlings are natural, such as predators including sharks, raccoons, foxes, and seagulls, many new threats to the sea turtle species have recently arrived and increased with the ever-growing presence of humans.
Source: http://en.wikipedia.org/wiki/Sea_turtle (retrieved August 19, 2011)