The Life Cycle of Sea Turtles (Beginner’s Guide)

Turtles are extraordinary reptiles that have roamed the world for more than 100 years. They boast of being the only animals that move around with a shell, where they can hide in case of impending danger. Different turtle species can be found in different locations, whether it’s in the ocean, on land, or in freshwater rivers and ponds.

While these cute, calm, and docile creatures have become an alluring attraction, few people understand their life cycle. Just as humans transition from a baby, a toddler, a child, a teenager, and an adult, turtles also follow a gradual growth pattern with four phases. The only difference is that turtles lay eggs and live for more than 100 years.

Keep reading if you want to learn about the turtle lifecycle and everything about taking care of the turtle at each stage.

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Lifecycle of Turtles

All turtles undergo a similar life cycle but may exude subtle differences in every growth stage. Unlike other animals, turtles have a complicated life cycle since they rely on the sea to nourish their bodies and sandy beaches and banks to nest. However, different turtle species live and reproduce in entirely different locations.

Red-eared sliders, which inhabit freshwater bodies like rivers, lay their eggs on the shores next to where they live and feed. Leatherback sea turtles, commonly found in the ocean, travel thousands of miles to lay eggs. Lastly, terrestrial turtles, such as Box turtles, lay their eggs on moist soils near water bodies or marshlands.

Typically, turtles go through four growth stages, including:

  • Egg Phase
  • Hatchling Phase
  • Juvenile Phase
  • Adult Phase

Eggs Phase

Female turtles move to their breeding locations during the nesting season. They are often near the shores where turtles lay eggs a few weeks after mating. Once they climb above the high tide-line or marshy ground, they dig a large hole with their front flippers.

They make a small groove with their hind flippers and lay eggs. Turtles can lay between 50 and 200 soft-shelled eggs, depending on the species. They then cover the nest with soil, camouflage them by throwing branches or debris with their hind flippers, and return to the water.

Unlike other animals that stay close to their eggs to provide security, turtles protect their eggs by burying them. Once they lay the eggs and cover them, they return to their feeding areas to replenish their energy stores and get ready for nesting season.

Turtle eggs are spherical or oval and have a softer texture than other animals’ eggs. The nesting process can take anywhere from 45 minutes to 5 hours. During the nesting season, a female turtle can make 2 to 8 nests to increase the chances of reproduction. If a predator uncovers one nest, there will still be other nests to hatch. 

Taking Care of the Eggs

When in captivity, turtles need to be provided with a nesting area similar to what they are used to in the wild. However, turtle owners need to maintain and take care of these nesting zones if they want the eggs to remain safe and hatch into offspring.

If you want the eggs to hatch naturally, you need to cover the nest with hardware cloth or chicken wire. This will help keep off predators such as raccoons but still allow sun and rain to get through.

If you want the eggs to hatch artificially, mark the top part of the eggs when getting them from the nest to ensure they maintain the proper orientation once transferred into the incubator. Remember to take extra care when handling and storing turtle eggs since they are extra soft and can quickly get damaged.

Use small Styrofoam or plastic containers with vermiculite to store and transfer eggs from the nest to the incubator. Once inside the incubator, ensure that the gees get adequate oxygen, temperature, and humidity.

Hatchling Phase

The next stage in a turtle’s growth cycle is the hatchling phase. Once eggs are laid and covered with soil, they incubate for 45-75 days, depending on the temperature. Essentially, the temperature of the sand surrounding the nest determines how long the eggs will take to hatch.

When inside the eggs, baby turtles develop a temporary tooth known as the caruncle. When it’s time to come out of the shell, baby turtles break the eggshell using the caruncle. As soon as the first hatchling emerges, the rest follow.

Once out of the shell, the hatchlings climb out of the nest and crawl to the sea. Usually, the hatchlings get out of the nest at night to escape heat exhaustion and avoid predators. The hatchlings crawl to the water as first as possible and start a multi-day swimming frenzy.

When they first hatch, baby turtles feature a leftover yolk sack on the bottom of their plastron. The yolk sack nourishes the turtle until it starts to scavenge for its food. Hatchlings have adequate energy to swim almost continuously for hours or days.

With the aid of strong currents, hatchlings are transported to the open-ocean habitat, where there are fewer predators and adequate food for baby turtles. The young creatures find shelter in algae mats, which act as their food source until they transition into the juvenile stage.

One interesting fact is that besides determining the incubation period, the temperature in the nest also determines the turtle’s gender. In warmer conditions, the eggs hatch to females and hatch to male turtles if it’s cooler.

This means that you can have a whole batch of eggs hatch into all males or females. However, it’s daunting to find a nest that has a uniform temperature. The bottom can sometimes be warmer than the top, leading to male and female turtles being hatched.

Taking Care of Hatchlings

For turtles in captivity, there are a few things that you ought to do to ensure that the hatchlings are comfortable and healthy. First, you should not disturb the hatchlings once they are out of the yolk. Since they come with a small yolk attached to the plastron, make sure that the yolk doesn’t burst as it could lead to death.

Additionally, you should provide them with a large aquarium to allow them to enjoy their first continuous swim. The hatchling needs to be fed every 1 to 2 days until they are a year old. However, remember that hatchlings don’t need to be fed the first few weeks since they’ll still be getting nourishment from the yolk sack. 

Juvenile Phase

The next growth phase for turtles after hatchling is juvenile. After spending a year or two in the oceanic zone, the hatchling becomes a juvenile and retreats to the coastal areas. They move to a highly productive spot in the sea, where they find enough food to eat until they become adults. These locations are known as foraging grounds or coastal areas.

Although foraging areas have plenty of food, they also tend to be home to several predators. For this reason, hatchlings have to wait until they have attained enough power to avoid and escape from predators in the coastal areas.

Research for the juvenile stage is scarce since it’s impossible to put a turtle tracker that will last until hatchlings transform into juveniles. Additionally, adding a foreign object to a baby turtle’s body also affects its buoyancy and might compromise its movement in the water. For this reason, the juvenile years are known as lost years since not much is known about them.

Taking Care of Juvenile Turtles

Juvenile turtles require more attention since they are at a stage where they need more food, more exercise, and more basking. Therefore, when taking care of a juvenile, these steps will ensure that it’s comfortable and happy:

  • Provide a sizeable turtle tank with a basking area and a large swimming area.
  • Ensure that the aquarium has an optimal temperature.
  • To promote growth and development, provide them with a healthy diet, protein-rich. However, be careful to avoid overfeeding your pet turtles.
  • Ensure that your baby turtle stays in a clean habitat.
  • Don’t handle juvenile turtles without necessity.


Essentially, turtles enter adulthood after 10 to 50 years, depending on the species. A turtle is said to be an adult if it’s sexually mature. However, it isn’t easy to know whether a turtle is an adult or from its physical appearance.

 Some turtles can grow bigger at a younger age, while others are small in size yet in their 30s. Conversely, female turtles can become bigger before they become sexually mature. The only way to determine if a turtle is sexually mature is to track its hatching date and follow its growth through up to adulthood.

Once turtles reach adult maturity, they feed and store adequate food resources and migrate to breeding areas. Male turtles move to these areas to mate, while female turtles move to these zones to nest.

The breeding zones can span hundreds to tens of thousands of miles away from the feeding spot. Most females return to the same nesting where they emerged. It’s believed that turtles return to mate and breed in the same beach or location where they appeared for the first time as hatchlings. The return of a mature turtle to its birth spot is known as natal homing.

While there might be excellent nesting areas nearby, most turtles prefer to return to where they were hatched. The process of natural selection explains that if a mother goes back to where she was hatched, there’s a high chance that her offspring will also survive.

How Mating Takes Place near the Nesting Area?

Once the mating season arrives, sexually mature male and female turtles move from their feeding areas to breeding areas next to nesting zones. During this period, male turtles are pretty aggressive and will try to mate with as many females as possible.

While female turtles only need sperms from one male to fertilize all the eggs, sometimes they get them from different turtles leading to multiple paternity. The aggressiveness of male turtles during the mating season means that multiple males can fertilize the eggs in a single female in a season.

Unlike females, which stay in one nesting area, males can visit several places to mate with as many females as possible. However, once they mate with a few females and move to various breeding areas without locating more females to mate with, they retreat to the feeding area and continue scavenging for food.

Taking Care of Adult Turtles

If you bring a sexually mature turtle into captivity, the only thing that will guarantee its happiness and health is consistent care. You need to provide an enclosure that replicates the natural habitat minus the predators. Below are turtle care tips you need to keep in mind:

  • Ensure that your pet turtle lives in a spacious tank. A rule of the thumb is to provide 10 gallons of water for every inch of the turtle’s shell.
  • The water temperature in the aquarium needs to be maintained between 75 and 85 degrees Fahrenheit.
  • Since sexually mature turtles tend to be territorial, ensure that you don’t keep more than one turtle in a single tank.
  • Give your turtles a healthy and balanced diet comprised of turtle pallets, vegetables, seeds, insects, fish, and fruits.
  • Water in the turtle tank should be kept clean at all times. Remove extra food after the turtle has eaten and clean and unclog the filters.
  • Provide a basking area where turtles can soak up and take in beneficial UVB and UVA light.
  • Finally, checkout for any signs of illness, including stinky shell, swollen eyes, loss of appetite, and discoloring of the cover. Any signs of sickness should be reported to a veterinarian specializing in turtle care. 

Final Verdict

Besides playing a crucial role in regulating the ecosystem, turtles are a unique attraction and make the best pets. With nearly all turtle species heading to extinction, it’s up to human beings to provide them with care and protection. However, to provide this care, you need to understand the life cycle of turtles.

Essentially, a turtle’s growth cycle spans four stages. These are the egg phase, hatchling phase, juvenile phase, and adulthood. To provide your turtle with the best care, you need to know the intrinsic needs of turtles at different growth stages.

Since most of the threats to turtles are related to human activities, learning about their life cycle should be the first step to understanding the problems these creatures face throughout their existence. 

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