Marine reptiles
Green sea turtle
Chelonia mydas
Epipelagic zone
The only sea turtle that is strictly herbivorous as an adult, the green turtle can travel thousands of kilometers just to return and nest on the exact beach where it hatched.
🗺️ Geographic range
Inhabits tropical and subtropical waters of the Atlantic, Pacific, Indian Ocean, and Mediterranean, nesting in over 80 countries and found along the coasts of more than 140.
📊 Population
Long classified as Endangered, the green sea turtle was reclassified as Least Concern by the IUCN in October 2025, following a roughly 28% global population increase since the 1970s — a success credited to decades of nesting-beach protection and fishing regulation. Some regional populations, particularly in the Indian Ocean, remain Vulnerable.
Habitat
- Pacific Ocean · Coral reef · Epipelagic zone · Permanent
🥚 Reproduction
Females breed only every 2–5 years, laying around 110 eggs per nest across several nestings spaced about two weeks apart.
Behaviour
- Diet
- Unlike other sea turtles, adults feed almost exclusively on algae and seagrasses, which gives their fat its characteristic greenish color (the source of the species' name).
- Hunting
- It does not actively hunt: it slowly grazes on algae and seagrass on the seabed.
- Communication
- Limited communication, mainly tactile and visual; no complex vocalizations known.
- Social life
- Largely solitary, it only gathers in numbers at nesting beaches or rich feeding grounds.
Physiology
- Anatomy
- Its heart-shaped shell and single-clawed front flippers make it the largest hard-shelled sea turtle.
- Respiration
- Pulmonary; it can slow its metabolism to stay submerged for hours without surfacing to breathe.
- Vision
- Good underwater eyesight, suited to detecting predators and recognizing nesting sites.
- Adaptations
- It has a magnetic sense that lets it imprint on the geomagnetic signature of its natal beach and return there to nest decades later.
🔗 Web of marine life
Predators
⚡ Its extraordinary abilities
- An internal magnetic 'compass' that lets it find its way back to its birth beach after years at sea
- The only sea turtle that is strictly vegetarian as an adult, playing a key role in keeping the seagrass meadows it grazes healthy
🏆 Records
Most dramatic conservation status recovery of a sea turtle
In 2025, the IUCN moved the green turtle directly from Endangered to Least Concern, skipping intermediate categories entirely — an unprecedented jump for the species.
Source: IUCN — Red List of Threatened Species
If you cross paths with this animal…
Risk: No danger to humans; it is a completely peaceful animal.
Behaviour: Generally calm and tolerant of swimmers and divers who keep their distance.
Advice: Never touch, chase, or approach a nest or a nesting female — nesting is highly sensitive to disturbance.
💡 Did you know?
- A green turtle can hold its breath for several hours while resting by drastically slowing its metabolism.
- Hatchling sex is determined by nest sand temperature: warmer sand produces more females.
