When did the firsts turtles appear?
The first turtles appeared during the Triassic period, 245 to 208 million years ago.
What are the different species of sea turtles?
Flatback, green, hawksbill, Kemp's ridley, loggerhead, leatherback, and olive ridley. The eastern Pacific green turtle, or black turtle, is often considered the eighth species, however, it is still unclear if they are genetically different enough to be considered a separate species from the green turtle.
Where can sea turtles be found?
Sea turtles live in warm and temperate oceans and seas around the world. There are no sea turtles in the Arctic Ocean.
How do sea turtles reproduce?
After mating in the ocean, female turtles come to the shore to lay eggs. Using the flippers, the female dig 50 cm-deep hole in the sand where she lays approximately 100 to 200 soft shell eggs. She covers the nest with sand, smoothes the sand so the nest cannot be easily seen, and she return to the water.
Do male sea turtles ever come back to the shore?
Male sea turtles almost never come back to the shore, except for Pacific green turtles that bask in the sun on the beach.
How is the sex of a turtle determined?
The temperature of the sand influences the length of the incubation and the gender of the hatchling turtles. Higher temperatures of the sand determine greater frequencies of females among the hatchlings.
How do sea turtles navigate?
Sea turtle migrate for hundreds and thousands of kilometers using the Earth’s magnetic field for orientation. Returning to lay eggs in often the same place where they were born, sea turtles keep an imprint of the location’s magnetic features.
What do they eat?
Depending on the species, the sea turtles can be herbivorous (feeding on seaweed and algae), omnivorous or carnivorous (eating sponges, squids, cuttlefish, sea cucumbers, and small crustaceans). The jaws are adapted to their diet.
What is threatening the sea turtles on land?
- Beachfront lighting can disturb the adult female and often disorients emerging hatchlings that instinctually follow the light of the moon towards the ocean.
- Coastal armoring (seawalls, bulkheads, and revetments) alters the beach and blocks the female from laying her eggs.
- Coastal construction changes the beach surface, increases light and noise in the area, and can lead to more pollution.
- Beach modification (renourishment) changes the type of sand, which can change the temperature, texture, and firmness. A nesting female may decide not to lay her eggs on this sand because it is too hard or too soft. Hatchling sex ratios may change because the new sand heats up more than the old sand.
- Storm erosion is a natural problem. If a beach loses sand due to a large storm, the female may be deterred by the small size of the beach.
- Dogs, raccoons, birds and people in some places eat sea turtle eggs or hatchlings.
What are the threats in the water?
- Birds, fish, crabs, and sharks eat hatchlings as they enter the water
- Sharks and humans are adult sea turtles’ only predators
- Adult turtles can be trapped in fishing nets and die of suffocation.
How long does a sea turtle live?
With so many obstacles, 1 out of 1000 sea turtles reaches the sexual maturity age, estimated around 30. They can live to be approximately 50-80 years old depending on the species.
Why are sea turtles important?
Sea turtles are an important part of the food web in the oceans; they control prey species and themselves providing food to larger predators. Sea turtles make the link between the seas and the coastal areas by carrying biological nutrients between different ecosystems. The health of the sea and of the ecosystems on the land is directly connected through turtles. Also, turtles generate revenues for ecotourism after becoming an attraction and increasing people’s interest in marine and coastal issues. They are “ambassadors of the oceans.”
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