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Planet Earth

Everything to Know About the Secret World of Sea Turtles

Sea turtles live long lives, and make large impacts to their habitat. Learn more about these marine reptiles.

By Jake ParksMar 6, 2024 1:00 PM
Green sea turtle swimming through the crystal clear lagoon at Lady Elliot Island on the Great Barrier Reef in Queensland Australia
(Credit: SeanScottPhotography/Shutterstock)

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In the serene yet treacherous waters of our planet's oceans, sea turtles have thrived for ages, silently helping maintain the equilibrium of aquatic life. These marine reptiles, which are emblematic of both endurance and tranquility, play vital roles in oceanic ecosystems. However, their existence is increasingly threatened by a host of serious challenges.

Take a deep dive into the life of sea turtles, exploring their diet, habitat, lifespan, threats to their existence, and what humans can do to help.

The Lives of Sea Turtles

(Credit: Tommy Daynjer/Shutterstock)

Sea turtles are marine reptiles that have been navigating the world's oceans virtually unchanged for some 110 million years. They belong to the order Testudines and are known for their large shells, which offer protection from predators. Unlike many other turtles and tortoises, sea turtles cannot retract their heads and limbs into their shells, and they have adapted flippers for swimming in the ocean.

Sea turtles play key roles in marine ecosystems, contributing to the health of seagrass beds and coral reefs, which in turn support a wide array of other marine life. Unfortunately, sea turtles face numerous threats, including habitat destruction, pollution, climate change, and bycatch in fishing gear. These challenges have led to the decline of sea turtle populations worldwide, prompting international conservation efforts aimed at restoring their numbers.

How Many Species of Sea Turtles Are There?

There are seven distinct species of sea turtles, each with its own unique set of characteristics, habitats, nesting habits, and dietary preferences. These species include:

  • Green

  • Hawksbill

  • Leatherback

  • Loggerhead

  • Olive Ridley

  • Kemp's Ridley

  • Flatback

Each species occupies a different niche in the marine environment, from shallow coastal waters to the open sea, and from tropical regions to more temperate zones.

Understanding the specific needs of each sea turtle species is essential for their conservation, as targeted conservation strategies are key to ensuring their survival.

How Big Can Sea Turtles Get?

(Credit: Leonardo Gonzalez/Shutterstock)

The size of sea turtles varies dramatically across species.

The leatherback is the largest of all sea turtles, growing up to 6 feet in length and weighing up to 1,500 pounds. Other species, like the Hawksbill and the Green sea turtle, are smaller, though they can still reach impressive sizes, with adults typically ranging from 2.5 to 4 feet in length and weighing several hundred pounds.

On the other end of the spectrum, a Kemp’s Ridley is the smallest sea turtle, averaging under 2 feet in length and typically weighing just shy of 100 pounds.


Read More: Why Baby Leatherback Sea Turtles Struggle to See the Ocean


Habitat and Migration of Sea Turtles

Sea turtles, known for their varied habitats, are found from the warm tropical shores to the colder, temperate waters, showcasing their remarkable adaptability. Unique among them, the leatherback sea turtle stands out for its ability to withstand the cold temperatures of the Pacific and North Atlantic, ranging as far north as the near-freezing waters off Greenland. And because leatherbacks don’t have a bony shell, they can also dive to depths of more than 3,000 feet.

The migratory behavior of sea turtles is equally impressive, with some species undertaking thousands of miles of travel between their feeding grounds and nesting beaches. Notably, female sea turtles exhibit a strong homing instinct, often returning to the exact beach where they were born to lay their own eggs.


Read More: Sea Turtles Use Shipwrecks As Artificial Reefs, And We Know This From Instagram


What Do Sea Turtles Eat?

(Credit: Rich Carey/Shutterstock)

The diet of sea turtles varies significantly by species. While some species are omnivorous, most adult sea turtles are specialized feeders.

For instance, green sea turtles are the only sea turtles that are herbivores, primarily feeding on seagrasses and algae, which gives them green-colored fat. Meanwhile, Hawksbills like to feed on sponges found in coral reefs. And leatherbacks and loggerheads, the giants of the turtle family, consume large quantities of open-ocean invertebrates like jellyfish, helping control jellyfish populations. (Unfortunately, this diet also makes leatherback and loggerhead sea turtles more likely to mistakenly ingest plastic bags floating in the ocean.)


Read More: Sea Turtles Are Eating Plastic Because It Smells Like Their Food, Study Finds


Lifespan and Survival: How Long Do Sea Turtles Live?

Sea turtles are known for their impressive longevity. They can live for several decades, with many species reaching 50 to 100 years in age. But this long lifespan contributes to their late maturity, where some species don’t breed until they are 20 to 30 years old.

A sea turtle’s journey to maturity is also fraught with peril. From the moment they hatch, sea turtles face countless predators and challenges, which is why only about one in 1,000 to one in 10,000 hatchlings survive until adulthood.


Read More: How Old Is the Oldest Sea Turtle?


A Species at Risk

(Credit: SaltedLife/Shutterstock)

Sea turtles play crucial roles in marine ecosystems, from maintaining healthy seagrass beds and coral reefs to controlling jellyfish populations. However, their survival hangs in the balance, largely due to human activities.

Fortunately, by understanding more about these magnificent creatures and the specific challenges they face, we can take better steps toward helping ensure sea turtles continue to thrive in our oceans far into the future.


Read More: Why Are Sea Turtles Endangered and How Can We Save Them?


Frequently Asked Questions About Sea Turtles

Can Sea Turtles Breathe Underwater?

Sea turtles cannot breathe underwater; they are air-breathing reptiles. However, they can hold their breath for several hours at a time. Depending on activity level, sea turtles can stay submerged for 4 to 7 hours. This allows them to undertake long dives while foraging for food or resting on the ocean floor.

Predators and Threats: What Eats Sea Turtles?

From the moment they hatch, sea turtles face a multitude of predators. On land, birds, crabs, and small mammals prey on eggs and hatchlings. In the ocean, sharks, large fish, octopuses, and occasionally marine mammals target young and adult sea turtles alike.

Conservation Status: Are Sea Turtles Endangered?

Unfortunately, most sea turtle species are classified as endangered or threatened, primarily due to human activities. Factors such as habitat destruction, pollution, climate change, accidental bycatch, and illegal hunting have significantly impacted sea turtle populations.

Conservation efforts worldwide aim to protect sea turtle nesting sites, reduce bycatch, and mitigate other threats to help these ancient creatures survive.

Population Status: How Many Sea Turtles Are Left?

Estimating the exact number of sea turtles is challenging due to their wide distribution and long lifespans. However, it's clear that their numbers have dramatically declined in recent decades. For example, evidence suggests the population of Eastern Pacific leatherbacks has declined some 90 percent over the past 30 years.

That’s why conservation programs and international cooperation are crucial for monitoring and protecting sea turtles.

Reproductive Habits: How Many Eggs Do Sea Turtles Lay?

Sea turtles are known for their remarkable nesting behaviors, often returning to the same beaches where they were born to lay their eggs. A female sea turtle can lay hundreds of eggs during a single nesting season, burying them in the sand to incubate.

However, the survival rate of these hatchlings is extremely low, with only a few per thousand making it to adulthood.

Rest and Sleep: How Do Sea Turtles Sleep?

Sea turtles have unique sleeping habits. They can sleep at the water’s surface or underwater, surfacing for air periodically. Some species find underwater resting spots nestled in coral or mud, where they can remain undisturbed, while others simply float at the surface.

Interaction with Humans: Do Sea Turtles Bite?

While generally not aggressive towards humans, sea turtles can bite if they feel threatened or cornered. These creatures are more interested in avoiding conflict than engaging in it.

It's essential to respect a sea turtles’ space and observe them from a distance, whether while snorkeling, diving, or during beach encounters.

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