Sea Turtle Life Cycle Explained [With Visual Infographic]

Sea Turtle Life Cycle

Female sea turtles come to the shore, dig a hole, lay their eggs, and leave. It takes 2 months for the eggs to hatch. The hatchlings then make their way up from the nests and run towards the water. We all know these parts. But what happens after that?

Most researchers have divided the sea turtle life cycle into 4 parts. Such as,

  1. Nesting period
  2. Hatchling
  3. Juvenile
  4. Adult

It is true that scientists do not know much about the life of a sea turtle. I have read a lot about sea turtles because of my personal interest and decided to write all I could find out on the life cycle of this species. So, if you are interested in exploring the world of these sea creatures, take a dive with me.

Sea Turtle Life Cycle

The life of a sea turtle is nothing less than a mystery to humans. The journey of a marine sea turtle starts from the beach, and then it spends all its time exploring the deep ocean.

Unfortunately, researchers can not track the whole life map of a sea turtle due to different limitations. Yet, they have come up with amazing facts that help us know these marine creatures better.

A sea turtle may have a lifespan of 50 to 100 years, depending on the subspecies. You can divide all years into 4 parts to understand the life events of this species more clearly. Such as,

  1. Nesting period or eggs
  2. Hatchling or baby
  3. Juvenile or the lost years
  4. Adult or the mating period

Every cycle of a marine turtle’s life is full of adventurous events. Without any further ado, let’s enjoy this visual infographic on the sea turtle life cycle.

sea turtle life cycle infographic

If you want a printable version of this amazing infographic for free, click here!

Nesting Period

Sea turtles look for a partner in mating season right after gaining sexual maturity. In most cases, the female marine turtles carry eggs if the coitus session goes successful.

Gestation Period

How long does the gestation of a female sea turtle last? Well, no one knows the exact answer because the females spend their time in the ocean. They only come to the shore when it is time to deposit the eggs.

However, scientists have observed that most sea turtle species nest within 2 to 3 weeks of mating. But some female marine turtles do not come to nest for 1 to 2 years. It is because the female turtles can carry the sperm of the males for years.

In Search Of A Nesting Place

So, when the egg deposition time approaches, the gravid sea turtles make their way to the seashore and prepare for nesting. Generally, marine turtles lay eggs at the same place they hatched. Also, most sea turtle species believe in community nesting.

Sea turtles prefer warmer tropical or sub-tropical beaches for nesting. You know the marine turtles have large flippers instead of webbed feet. Though the flippers are a great help in swimming in the deep ocean, they are totally useless while walking on the shore.

It takes huge energy and effort for the gravid turtles to come to the beaches. Observers suggest that the sea turtles use their flippers to drag their bodies all the way to the shore.

In some cases, the female sea turtles get tired and give up on the egg deposition. Again, sometimes, tourists or locals disturb the creatures. It makes them abandon their struggle and head back towards the sea. The scientists refer to this incident as a false crawl.

You may not understand and irritate the struggling sea turtles for fun. But here is the fact. A gravid marine turtle needs to nest on a sandy beach. If the turtle lays the eggs underwater, there is barely any chance of hatching.

Neither the water pressure nor the temperature is suitable for hatching the sea turtle’s eggs. Moreover, the embryos require oxygen for the healthiest development. They get it via the egg membrane.

While covered with water, embryos can not breathe air, which eventually hampers their survival. Hence, do not mess with the marine turtles taking a stroll on a beach or looking for a nesting place.

Now, when the gravid sea turtle is up on the warm sandy beach, she will find a suitable nesting area. The first thing the turtle does is clearing up the debris and other dirt. Then, she will create a body pit and take a rest.

Egg Chamber Preparation

Once the turtle is all charged up, she will start digging a hole using her hind flippers. You will be surprised to see the depth of the nesting chamber.

The gravid turtle only stops when her flippers can not reach deeper and pull no more sand. The dug body pit or egg chamber is somewhere between 14 to 22 inches deep.

A female sea turtle does not nest every year. Instead, it lays eggs every 2 to 4 years and nests 4 to 6 times in one season. And so, the gravid sea turtle might have to dig 2 to 8 nesting chambers to maximize the egg deposition.

Laying Eggs

As the nesting chamber is ready, the gravid sea turtle will be depositing her eggs soon. The egg-laying is a long process and takes around 45 minutes to 5 hours.

A mother turtle does not want any interruption during these hours. Hence, some female sea turtles choose the night hours for depositing their eggs.

Also, during the nighttime, there is a lesser risk of predator attack or heatstroke. Some species might nest in the daytime, for example, Olive Ridley’s sea turtle and Hawksbill sea turtle.

While laying eggs, the gravid turtle enters a trance-like or semi-unconscious state. The mother deposits eggs in batches of 2 or 3. The clutch contains around 50 to 200 eggs, depending on the species. Generally, the smaller sea turtle species lay more eggs.

Sea turtle eggs are tiny in size. Each is about the size of a ping-pong ball. The mother sea turtle also releases a gelatinous secretion while depositing the eggs. This slimy element keeps the eggs moist and protected.

You know the sandy soil is not hard. So, the laid eggs do not get damaged. At the time of deposition, the eggshells stay soft and slightly bouncy. So, the yokes do not feel any force at all.

The soft eggshells are also the medium of oxygen and moist exchange for the embryos.

Covering Up The Tracks

Now that the mother sea turtle has completed the egg deposition, she will paddle the sands back on the hole. She camouflages the nest with sand using only her flippers. The purpose of this act is to protect the eggs from predators. The concealed chamber is also necessary to control the suitable incubation temperature inside the nest.

Once the sea turtle finishes her job, she hurries back to the water and takes a complete rest for 10 to 15 days. At the end of each nesting season, the female sea turtles return to their feeding areas.

With a proper diet, the female turtles try regaining the energy they have spent, and also, these turtles take preparation for the next breeding season. Generally, it takes more than a year for the turtles to get ready for another nesting season.

Hatching

Well, the mother sea turtles never return to their eggs anymore. The embryos develop on their own. It generally takes 6 to 8 weeks for the eggs to hatch.

However, the period depends on the temperature of the incubation chamber. Generally, clutches in the hotter zone hatch in a short timeframe.

Do you know the temperature also plays a role in the sex determination of unborn sea turtle babies? Scientists suggest that the eggs in the cooler zone yield male turtles. On the other hand, eggs in the hotter zone produce female sea turtles.

The deeper the nesting chamber goes, the more the temperature drops. So, those bottom eggs will hatch as males. Again, the upper portion of the clutch is hotter and will yield female turtles.

It can apparently seem that the nesting period is only part of the female marine turtle life. But no. The life cycle of each sea turtle starts as an egg and from one of those sandy incubator chambers.

Exploring The Sea As Hatchling

Within 60 days of incubation, the eggs will hatch. The babies coming out of the eggs are not a smooth event. Do you know sea turtle hatchlings have egg teeth or caruncles?

Yes, these teeth-like outgrown parts help the babies break the eggshell and get out of it. The caruncles of the hatchlings fall off within weeks or months.

When the first hatchling emerges from the egg, all its fellow siblings follow the way. It is believed that if one hatchling is trying to break the eggshell, the others can sense the act. And eventually, all the babies do the same thing.

You know, the mother sea turtles peck down the sand with great care. So, coming out of the nest is not easy for newborn sea turtles.

The hatchlings put a collaborative effort to make a way up. Generally, the turtles beneath give a push and help the top hatchling climb up. It might take 3 to 5 days for the hatchlings to reach the sandy beach.

A newborn sea turtle is barely 2.5 inches long and weighs around 30 grams. How big can a sea turtle get? Check this article.

Though the gravid sea turtle deposits 50 to 200 eggs, less than 1% of these can make it to the end. Around 20 to 40% of the egg yolks stay undeveloped. Thus the embryos do not have the desired growth.

On top of that, predators are always on a hunt for the nest. Vultures, raccoons, dogs, and sea debris destroy thousands of sea turtle eggs every year. Again, you will be shocked to know that locals often dig out the eggs and sell them for financial gain.

After winning all the struggles, once the hatchlings set foot on the beach, they run towards the sea. Generally, hatchlings come out of the nest during nighttime. The darkness protects the babies from predators and human interaction.

The babies will swim for days into the water out of excitement and adapt to the new life. The whole time the hatchlings survive on the stored yolk energy.

The strong ocean currents transport the hatchlings to the deep sea. When the babies reach deep water, their struggle begins. Primarily the baby sea turtles feed on the seagrass, Sargassum, and other omnivorous diets.

Journey Of A Juvenile

Right after the moment a sea turtle hatchling leaves the nest, it gets harder to keep track of its life. Finally, after years, the turtles keep coming to the neritic feeding areas.

You can ask me what happens to a sea turtle in between those years. Honestly, nobody can answer the question. But yes, the scientists assume that the babies go to an island and make their living there.

Generally, those untracked years of a sea turtle’s life are often referred to as lost years.

When they make their comebacks, they are no longer babies but juveniles. Usually, the juvenile sea turtles stay in the coastal areas until they grow mature.

Why do sea turtles come to the neritic feeding areas? You know the foraging grounds contain more food opportunities and fewer predators than the open sea.

Juvenile sea turtles spend years in these areas to gain strength and grow in size. Otherwise, they can not fight the predators of the deep sea.

Sea turtle species like Green sea turtles, Hawksbill sea turtles, and loggerhead sea turtles stay at the foraging grounds until the age of 10 to 15. To adapt to the new surroundings, these turtles bring changes in their diet.

The sea turtles depend on seagrass, seaweed, coral, and rocky leaves during those juvenile years. From time to time, the creatures might get hold of small invertebrates. Get details of the feeding habit of a sea turtle from this article.

However, experts haven’t traced the Olive Ridley’s sea turtle and leatherback sea turtles on the coastal areas. It proves that these two species spend both their development and adult years in the open sea.

So, yes, most juvenile sea turtle species come to the foraging grounds to reserve energy and grow bigger in size until they gain maturity. Once the turtles become sexually mature, they migrate to the breeding areas in search of a mate.

Sea Turtle SpeciesSexual Maturity
Leatherback sea turtle10 to 15 years
Green sea turtle25 to 50 years
Hawksbill sea turtle20 to 25 years
Loggerhead sea turtles25 to 35 years
Olive Ridley sea turtles10 to 15 years
Kemp’s Ridley sea turtles10 to 15 years
Flatback sea turtles10 to 50 years

Adulthood

Over the years, the sea turtles gain sexual maturity and preserve energy to escape any upcoming dangers. When it is time, the males and females will migrate to the breeding areas. Usually, the turtles have to swim hundreds or thousands of kilometers to get there.

In the breeding season, both the male and female sea turtles have different roles. The males try to get involved in coitus with as many females as possible. Generally, they act aggressively during the season.

After successful mating, male marine turtles have no other role to play in the family matter. So, they leave the breeding areas and return to the feeding zone.

On the other hand, one successful mating is enough for the female sea turtles. Yet, they try to mate with multiple partners to fertilize as many eggs as possible. The gestation period of the females lasts for 2 to 3 weeks. During this time, they stay in the sea and start swimming towards the nesting areas.

Generally, the female sea turtles nest at their birthplace. The phenomenon is called natal homing. After laying the eggs, the mothers return to the feeding zone and prepare for the next breeding season.

You know sea turtles do not nest every year. They will deposit 50 to 200 eggs in one season and then wait for 2 to 4 years. Some females carry the sperm of males for years before fertilizing the eggs.

At what ages do the sea turtles get sexually matured? No one knows the exact answer. It is hard to come to any conclusion just by observing these turtles’ appearances or sizes.

Scientists assume that a sea turtle might become sexually active in between 10 to 50 years, depending on the species. And the female sea turtles can nest for 80 years of their age.

Here is a chart indicating sexual maturity ages of different sea turtle species,

Check this article if you can not identify the species of a sea turtle. I swear it is fun.

Conclusion

The sea turtle life cycle is interesting and mysterious to us. Scientists are trying to collect as much information as possible to come to a full conclusion on this species. If you ever spot a sea turtle strolling on the beach, do not irritate it. Instead, call an emergency organization if you sense the creature is in danger.

Muntaseer Rahman

I have been keeping turtles as a pet for many years now. I’ve fallen in love with these cute pets from the moment I saw them. That’s why I am writing articles to share my turtle keeping knowledge with you.

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