Guide to sea turtles: facts, threats, and conservation

The captivating world of sea turtles

Sea turtles, revered as ancient mariners of our oceans, have been gracing our waters for an astonishing 110 million years. These resilient creatures play a vital role in the health and balance of marine ecosystems worldwide. From the Leatherback to the Hawksbill, each of the seven species of sea turtles brings a unique set of characteristics and contributions to our oceanic biosphere. However, despite their ecological importance and awe-inspiring existence, every single species of sea turtles is facing a barrage of threats, pushing them closer to the brink of extinction.

In this guide, we journey into the world of these magnificent creatures, exploring their unique attributes, the threats they face, and the ongoing conservation efforts aiming to secure their future. Join us as we dive deep into the life of sea turtles, understanding their crucial role in our planet’s wellbeing and what we can do to protect them.

Seven species of sea turtles

Beneath the waves of the world’s oceans, seven unique species of sea turtles navigate the depths, each with its own set of characteristics, behaviors, and roles within their ecosystems. Let’s meet each one of these remarkable mariners and learn more about their lives, their struggles, and their importance to our planet.

NameConservation StatusAverage SizeDietMain Threats
Leatherback (Dermochelys coriacea)VulnerableUp to 1.8m, 640kgGelatinous zooplanktonHabitat loss, incidental capture, marine pollution, climate change
Loggerhead (Caretta caretta)VulnerableUp to 90cm, 135kgMollusks, crustaceans, fish, jellyfishHabitat loss, incidental capture, coastal development, beachfront lighting
Green (Chelonia mydas)EndangeredUp to 1.5m, 190kgSea grasses, algae (adults); crabs, jellyfish (juveniles)Habitat destruction, illegal hunting, incidental capture, climate change
Flatback (Natator depressus)Data DeficientUp to 1m, 90kgSea cucumbers, jellyfish, prawns, mollusksHabitat degradation, pollution, incidental capture
Olive Ridley (Lepidochelys olivacea)VulnerableSize not providedCrustaceans, mollusks, tunicates, fishTrawling, coastal development, climate change
Hawksbill (Eretmochelys imbricata)Critically EndangeredSize not providedReef spongesHabitat loss, pollution, climate change, illegal shell trade

Leatherback (Dermochelys coriacea)

Status: Vulnerable

Description: The Leatherback turtle is the largest among sea turtles, capable of reaching over 1.8 meters in length and nearly 640 kilograms in weight. Unique among sea turtles, Leatherbacks don’t have a hard, bony shell. Instead, their carapace is somewhat flexible and almost rubbery to the touch.

Habitat: Leatherbacks have a wide distribution, found in every ocean except the Arctic and Antarctic. They are remarkable for their long migrations, often traveling an average of 3,700 miles each way between feeding and breeding areas.

Diet: Leatherbacks primarily feed on gelatinous zooplankton, especially jellyfish.

Threats: Major threats to Leatherbacks include habitat loss and incidental capture by fishing operations. They are also vulnerable to marine pollution and climate change.

Interesting Fact: Leatherbacks are capable of diving to depths greater than 1,000 meters in search of food, which is deeper than any other turtle.


Loggerhead (Caretta caretta)

Status: Vulnerable

Description: The Loggerhead sea turtle is known for its large head, which houses powerful jaws capable of crushing an adult queen conch. Loggerheads are among the largest hard-shelled turtles, with adults growing up to 90 cm in length and weighing around 135 kg.

Habitat: Loggerheads inhabit every ocean except the Arctic and Antarctic. They prefer coastal habitats where their food sources are abundant, and they are known for their vast migrations, often covering thousands of miles across ocean basins.

Diet: Loggerheads feed on a variety of marine life, including mollusks, crustaceans, fish, and even jellyfish. Their strong jaws enable them to easily crush and consume their prey.

Threats: The Loggerhead sea turtles face threats due to worldwide habitat loss and incidental capture by fishing operations. They are also affected by coastal development and beachfront lighting.

Interesting Fact: Female Loggerheads, like other sea turtles, return to the very beaches where they were born to lay their eggs. The nesting process involves digging a hole in the sand, depositing a clutch of up to 100 eggs, and covering the nest before returning to the ocean.


Green (Chelonia mydas)

Status: Endangered

Description: The Green Sea Turtle stands out for its distinct greenish color due to a layer of fat beneath its shell. They are among the larger sea turtle species, with adults typically reaching up to 1.5 meters in length and weighing up to 190 kilograms.

Habitat: Green turtles have the most numerous and widely dispersed nesting sites among the seven sea turtle species. They inhabit every ocean, barring the Arctic and Antarctic, with significant populations in the Atlantic and Pacific Oceans.

Diet: While Green Sea Turtles start life as omnivores, consuming invertebrates like crabs and jellyfish, they transition to an entirely herbivorous diet as adults, primarily feeding on sea grasses and algae.

Threats: Major threats to Green turtles include habitat destruction, illegal hunting for their meat and eggs, and accidental capture in fishing gear. Climate change, resulting in rising sea levels and temperatures, also poses a significant threat to their nesting sites.

Interesting Fact: Green turtles were once highly sought after for their body fat, a key ingredient in the popular delicacy known as ‘green turtle soup‘.


Flatback (Natator depressus)

Status: Data Deficient

Description: Flatbacks are unique among sea turtles in that they have a flat body shape, as their name suggests. They are medium-sized turtles, typically reaching up to 1 meter in length and weighing up to 90 kilograms.

Habitat: The Flatback turtle has one of the smallest geographic ranges of all sea turtle species. They are the only endemic sea turtle species, nesting solely along the northern coast of Australia and inhabiting the continental shelf between Australia, southern Indonesia, and Papua New Guinea.

Diet: Flatbacks feed on a variety of invertebrates, including sea cucumbers, jellyfish, prawns, and mollusks.

Threats: Since Flatbacks are concentrated in a limited geographical area, any disturbances can have a significant impact on their population. Major threats include habitat degradation, pollution, and incidental capture in fishing gear.

Interesting Fact: Flatbacks are the least studied of all sea turtle species, in part due to their limited distribution range.


Olive Ridley (Lepidochelys olivacea)

Status: Vulnerable

Description: The Olive Ridley sea turtle is recognized for a unique phenomenon known as ‘arribadas,’ in which they nest in mass numbers simultaneously. Among all sea turtles, Olive Ridleys are the most abundant.

Habitat: Olive Ridleys can be found in all oceans except the Arctic and Antarctic. Their exceptional nesting behavior brings hundreds to thousands of females to the same beach for egg-laying.

Diet: Being omnivorous, Olive Ridleys have a varied diet that includes crustaceans such as shrimp and crabs, mollusks, tunicates, and fish.

Threats: The most significant threats to Olive Ridleys are trawling, coastal development, and climate change, which significantly impacts their nesting beaches and marine habitats.

Interesting Fact: Olive Ridleys exhibit an extraordinary natural spectacle known as ‘arribadas‘, a Spanish term for ‘arrival,’ where they come ashore in hundreds or even thousands to nest simultaneously.


Hawksbill (Eretmochelys imbricata)

Status: Critically Endangered

Description: Hawksbill turtles are small, agile sea turtles, named for their hawk-like beak. They are recognized for their beautiful, translucent shell, which was historically exploited for use in tortoiseshell jewelry.

Habitat: Hawksbill turtles can be found in all oceans, excluding the Arctic and Antarctic, with a preference for tropical waters of the Atlantic, Pacific, and Indian Oceans. They are fond of coastlines rich in sponges and easily accessible coral reefs.

Diet: Hawksbills primarily feed on reef sponges, a unique dietary preference among sea turtles. Their sharp, pointed beak enables them to extract these invertebrate organisms, whose bodies contain indigestible glass needles.

Threats: Major threats to Hawksbills include habitat loss, pollution, and climate change. Their overexploitation for the tortoiseshell trade also poses a significant risk. Despite an international ban on Hawksbill shell trading (also known as ‘tortoiseshell’), illegal trafficking continues to persist.

Interesting Fact: The Hawksbill sea turtle plays a crucial role in maintaining the health of coral reefs. By feeding on certain types of sponges that can outcompete corals for space, Hawksbills help preserve the biodiversity of these valuable ecosystems.


Sea turtle lifespan and behavior

The remarkable lifecycle of sea turtles, originating on sandy coastlines and extending across the vast expanses of the ocean, is characterized by extended periods of survival, procreation, and migration. This lifecycle is instrumental to both the continuity of the species and the stability of marine ecosystems.

From incubation to maturity

The journey of a sea turtle commences as a tiny, tough-shelled egg hidden in a sandy nest. Amazingly, through a phenomenon known as natal homing, female turtles return to their own birthplace to deposit their eggs. Following a gestation period that varies among species but generally lasts around two months, the hatchlings emerge and embark on a dangerous trek to the ocean, facing predators such as birds, crabs, and various other creatures hatchlings’ journey.

Upon reaching the ocean, the hatchlings enter the “lost years” – a phase that lasts from a few years to over a decade. During this period, the young turtles mature within the open ocean. This stage of the lifecycle is less well understood due to the challenges in tracking these diminutive, elusive creatures across the vast oceanic expanses.

As they get older, sea turtles travel to feeding grounds, often coastal regions abundant with seagrass and other food sources. They continue to develop until they achieve sexual maturity, a stage that can take anywhere from a decade to half a century to reach, depending on the species. Upon maturing, adult turtles reinitiate the cycle by reproducing and laying their own eggs maturity and reproduction.

Migratory patterns, reproductive behavior, and dietary habits

Sea turtles, including the most sizable species – the leatherback sea turtle, are global voyagers, undertaking impressive migrations covering thousands of miles.

Sea turtles are generally solitary creatures that mainly gather for reproduction. During the mating season, males and females congregate in waters close to nesting beaches. After mating, the females return to the shorelines to deposit their eggs, sometimes creating several nests within a single season reproductive behaviour.

The dietary habits of sea turtles vary with their species and age. Some are omnivorous, consuming a combination of plant and animal matter, while others have more specialized diets. For example, green sea turtles predominantly consume seagrasses and algae, qualifying them as herbivores. In contrast, hawksbill turtles eat sponges, contributing to the balance of coral reef ecosystems.

In spite of the complex and formidable lifecycle of sea turtles, they significantly contribute to the wellbeing and stability of marine ecosystems. Given that many sea turtle species are now classified as threatened or endangered, their preservation and conservation are crucially important.

Threats to sea turtles

Sea turtles, despite their global reach and ancient lineage, face myriad threats, pushing them closer to the brink of extinction.

Direct human impact

One of the most direct human impacts on sea turtles is the collection of their eggs for consumption. Turtles are also hunted for their meat, and in the case of the hawksbill, their beautiful shells are poached for the illegal wildlife trade. Sadly, even beachfront development for human recreational activities can destroy crucial nesting sites, disturbing turtles during the sensitive nesting process.

Bycatch and fishing gear

Sea turtles often become unintended victims of large-scale commercial fishing techniques. They get caught in longlines, trawls, gillnets, and on baited hooks set for other marine species. This incidental catch, or “bycatch,” often results in severe injuries or death.

Pollution and marine debris

Our oceans are filling up with plastic and other forms of pollution at an alarming rate. Turtles can mistake these items for food, leading to ingestion that can cause severe health issues or death. Additionally, turtles can become entangled in marine debris, rendering them unable to swim, feed, or surface to breathe.

Climate change

Climate change is having a profound impact on sea turtles. Warming ocean temperatures can alter currents and affect the abundance and distribution of prey species. Rising sea levels and increased storm intensity can erode nesting beaches, while higher sand temperatures can influence the sex ratio of hatchlings, potentially leading to population imbalances.

Conservation efforts

In the face of these threats, numerous conservation efforts are underway worldwide to help protect and restore sea turtle populations.

Legal protection and regulation

Many countries have laws in place to protect sea turtles and their habitats, including prohibitions on hunting, egg collection, and trade in sea turtle products. At the international level, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) bans the international commercial trade of sea turtles and their products.

Community-Based Conservation

Local communities play an integral role in sea turtle conservation, as they are often located near vital turtle habitats. Numerous projects worldwide involve community members in turtle conservation, providing alternative livelihoods that reduce reliance on turtle exploitation.

Research and monitoring

Ongoing research and monitoring are crucial for understanding sea turtle population trends, behavior, and threats. Techniques such as satellite tracking allow scientists to monitor sea turtle migrations and identify important feeding and breeding areas that might need protection.

Bycatch reduction measures

Technological advancements such as Turtle Excluder Devices (TEDs) in trawl nets allow captured sea turtles to escape while retaining the intended catch. Regulations requiring the use of such devices can significantly reduce bycatch-related turtle deaths.

How you can help

Preserving sea turtle populations is not just the work of scientists or conservation organizations—it is a responsibility we all share. Each of us can make a positive difference with simple actions in our daily lives or during our vacations. Let’s delve into how you can contribute to this noble cause.

Responsible tourism

If you’re visiting a nesting beach, follow local guidelines to minimize disturbance to nesting turtles and hatchlings. Avoid using flashlights or flash photography on the beach at night, as these can disorient turtles.

Reduce, reuse, recycle

By reducing plastic use and properly disposing of waste, we can help decrease the amount of plastic debris in our oceans.

Support conservation organizations

Many non-governmental organizations are working hard to protect sea turtles. Your support, whether through donations or volunteer work, can make a big difference.

Spread the word

Educate others about the threats to sea turtles and what they can do to help. The more people know, the more they can contribute to conservation efforts.

Sea turtles have been part of Earth’s marine tapestry for millions of years. These magnificent creatures play a critical role in maintaining healthy oceans. Our actions today will determine the fate of these ancient mariners and the future health of our oceans.


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