Centre for in situ Observational Oceanography

Turtle Tracking

Sea Turtles
Species Information

What are Sea Turtles ?

Sea turtles are large air breathing REPTILES. They live in the sea, but must rise to the surface to breathe air.

Like tortoises, sea turtles have a shell. Their shell consist of an upper part (carapace) and a lower section (plastron). They have hard scales (scutes) that cover all over the carapace (except Leatherback turtles). The number of scutes is different for each species of sea turtle.

Sea turtles do not have teeth. They have a strong beak that they use to crush their food (crustaceans for example) or remove algae from their substrate. Their biology is also adapted to a very salty diet : turtles have salt glands that remove excess salt taken in with food. The salt solution drips out of their eyes and looks like tears.

Often, sea turtles are believed not to have ears, because there are no visible holes on the side of their head. However, they do have eardrums, which are covered by skin.

Each species of sea turtle eats, sleeps, mates and swims in distinctly different areas of the ocean. Therefore the turtles do not compete with each other for their food or space.

Turtle Reproduction

Most of the turtle's life is spent in the sea, but females must come onto the beaches to lay their eggs. All sea turtles begin their lives as tiny hatchlings on land. Along the South African coast lines nesting occurs between October and February.

The eggs incubate for about 60 days, depending on the surrounding temperature. The temperature also has an effect on the sex of the juveniles. Cooler (20-24°C) clutches result in a male dominated clutch while warmer (29°C) nests produce females. Clutches laid between seasons produce both male and females.The hatchlings cut themselves out of the egg using a special egg tooth on the end of their beaks, and then slowly stretch their limbs. The hatchlings emerge after dark, when it is cooler and safe from predatory birds.They then move down to the water. During their scramble to the sea, ghost crabs eat many of the hatchlings. Once they are in the water they are very vulnerable to predators such as kingfish and sharks. It is estimated that only 1 or 2 hatchlings out of 1000 that enter the sea will survive to maturity.

Turtle Conservation

Out of the 7 species of Sea Turtles, 3 are "endangered" or "critically endangered", and 3 are classified as "vulnerable". Their numbers are dwindling every year, due to poaching, diseases and pollution. It is therefore essential that every effort be made to ensure the future survival of these creatures.

Want to know more about these fantastic turtles ? Download the PDF below !

Fact about Sea Turtles - PDF download

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