Eggs laid in each nest
Sea turtle species
Determines the sex of a sea turtle egg
Sea turtles are the only species of turtle that live in the open ocean and cannot pull their heads or flippers into their shells. They are quite large, measuring between one – three meters when fully grown. Sea turtles have salt glands behind their eyes to remove extra salt from the seawater they drink and the food they eat, where salty tears roll out of the corner of their eyes as if they are crying. Sea turtles also have flippers, while other turtles have feet.
There are eight species of Sea Turtles that are divided into two Family groups. Family Dermochelyidae, contains one species of sea turtle. Leatherback sea turtles, Dermochelys coriacea, are found in all oceans, from Labrador, Iceland and Alaska to Argentina and Australia. Family Cheloniidae contains five genera, and possibly seven species of sea turtles.
Green sea turtles, Chelonia mydas, are found mainly in warm oceans; Chelonia agassizii inhabits the Indian and the warmer waters of the Pacific Ocean Loggerhead turtles, Caretta caretta, are found in tropical and subtropical waters Hawksbill sea turtles, Eretmochelys imbricata, live in the Atlantic, Pacific and Indian Oceans Kemp’s ridley, Lepidochelys kempii, lives in the Atlantic Olive ridley, Lepidochelys olivacea, is found in the Pacific.
Like all reptiles, sea turtles lay eggs. They can lay up to 100 eggs in each nest. Female sea turtles crawl onto the beach and dig u-shaped holes in the sand above the high tideline. In one breeding season, each female can dig several nests. There is usually an interval of 10-15 days between the laying of each batch, called a clutch, of eggs. Females spend the time in between laying clutches at sea. Nesting seems to occur in two and three-year cycles. Hatching is one of the most dangerous periods of a sea turtle’s life. Young turtles must pass many hungry predators as they crawl across the sand to the ocean. Once young male sea turtles reach the safety of the ocean, they may never set flipper on shore again.
All sea turtle species are considered endangered or threatened in at least part of their ranges.
The nesting habitat of all sea turtle species is being disturbed or destroyed by human action through urban development and recreational uses. Developments also create light pollution from beachfront properties, which causes hatchling sea turtles to have difficulty finding their way to the ocean. They will travel towards the brightest lights rather than the sea. Many sea turtles drown when they are caught in fishing nets and shrimp trawls. Sea turtles are also hunted for their meat, their eggs (eaten as food and aphrodisiac), and for calipee (cartilage found in the plastron or the shell on the underside of the turtle) which is used to make soup. Their shells are used for jewelry and other decorative items. Their skin is used to make leather, especially from the leatherback sea turtle. Sea turtles will also often mistake our garbage for food. Plastics (leatherbacks often mistake the plastic for jellies, their main food item), rubber, fish-hooks, and other miscellaneous items can block and damage the sea turtle's digestive track causing infections and starvation.
If you see a sea turtle off the coast of British Columbia, we would love to hear about it. Report your sighting at www.wildwhales.org.
Two species of sea turtle are commonly found in British Columbia. The leatherback sea turtle migrates to BC from South East Asia (Malaysia / Indonesia) in the summer in search of sea jellies. The green sea turtle is a tropical species but occasionally may follow a warm current northward and end up in British Columbia or even Alaska waters. There are two forms within the same species: the tropical green turtle and the black turtle, which is more often found closer to the North American coast.
Hatchlings find the sea by heading towards light—the ocean is the brightest source of light at night. Some beachfront resort owners turn off their lights at night to avoid confusing the hatchlings. This prevents them from becoming stranded high above the beach and away from the sea.
The sex of baby turtles is temperature-dependent. For example, if loggerhead eggs are incubated at less than 28°C, all the hatchlings turn out male. If the eggs are incubated at 35°C or warmer, all eggs hatch out as females. At temperatures between 28°C and 35°C, both male and female babies are hatched.
Carr, Archie. 1967. So Excellent a Fish. Garden City, N.Y.: American Museum of Natural History
Lutz, Peter and John Musick. 1996. The Biology of Sea Turtles. Boca Raton, FL: CRC Press
National Research Council. 1990. Decline of the Sea Turtles. Washington, D.C.: National Academy Press. Marine Turtle web page. National Oceanic and Atmospheric Administration.
Sea Turtle Portal. National Oceanic and Atmospheric Administration.
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