Sea Turtle Life Stages Explained

Sea turtles have floated around in our oceans for more than 110 million years. From loggerheads to flatbacks, these resilient marine creatures overcome some of the toughest survival odds time and time again.

With such a remarkable life cycle and important link to marine ecosystems, we’re here to share everything you need to know about the lives of sea turtles.

How long do sea turtles live?

Sea turtles endure one of the hardest and most dangerous journeys to survival. If they can make it through all the life stages leading up to adulthood, their natural lifespan is 50 to 100 years.  

The lifespan can be difficult for scientists to track and document accurately, though, since they spend their lives migrating across oceans.

Sea turtle life stages 

Sea turtles cycle through four key life stages, starting life as eggs and ending with adulthood. Let’s explore each stage in more detail below.

Egg

During hatching season in late summer, females dig large nests in the sand where they will lay their eggs. The process is long and requires a lot of effort since the nest must properly protect the eggs and maintain the right temperature.

Adults can lay up to 100 eggs each time, and the eggs are collectively known as a clutch. Females return to the ocean during the incubation period, which can last up to 70 days.

The sex of the offspring is determined by the nest temperature. The warmer the nest environment (around 31°C), the more female-dominant the hatchlings will be, while in colder temperatures (28 °C), the hatchlings will mostly be male. The eggs are laid on top of each other so that those lower down in the nest are more likely to be female, and the ones higher up are male. This is intended to create a balanced population amongst the hatchlings.

Hatchling 

Hatchlings will use an egg tooth called a caruncle to break through the egg, which may take up to 7 days and usually happens at night when temperatures are lower and fewer predators are around.

Leaving the nest and heading towards the ocean is one of the most critical moments in the survival of the hatchlings, and unfortunately, due to dehydration and predators like birds and crabs, very few will make it.

Juvenile 

As juveniles, sea turtles rely on the energy consumed from their yolk sacs to begin swimming and build strength quickly. They must swim for around 24 hours to move away from offshore and nearshore dangers and reach deeper waters where their survival odds are better.

After the initial swim into the water, they enter a phase called the ‘lost years’, which can last up to a decade. During this time, they must grow bigger and stronger by swimming, riding ocean currents and feeding on plankton, jellyfish, and other small marine organisms. This phase is critical to their survival and the marine ecosystems as they become more established in their habitats.

This is another incredibly dangerous stage in a sea turtle’s life, and the survival rate is sadly low. As turtles grow, they should gain strength, establish habitat territories and begin navigating large areas of the ocean to help them make it to adulthood safely.  

Adult

As adult sea turtles reach maturity, they begin migrating thousands of miles from their feeding habitats to the shorelines for mating and nesting. Reaching maturity can take up to 30 years, depending on the species and habitat conditions. Because it takes so long, sea turtles are vulnerable for much longer, which is why it’s so remarkable that these marine creatures have been around for so long.

Adult sea turtles have adapted to live on land and in the sea to help with the nesting process. Females will return to the same beach they have previously hatched on – this process is called natal homing. The female turtles use the Earth’s magnetic fields as a natural compass to find their way back, often waiting until nightfall to begin the nesting process.

Learn more about our sea creatures at Blue Reef Newquay

Sadly we have recently lost our own loggerhead turtle, Omiros. He spent the last 17 years as a huge part of our Blue Reef Aquarium family, after being rescued off the coast of Greece.

You can learn more about Omiros’ story and incredible legacy he’s left at our aquarium in this special blog.