Sea turtle species



The beautiful patterns on their shells, made up of overlapping scales – or scutes – are extremely desirable, and expensive. Sadly, this means the turtles have been hunted for thousands of years, their shells sold as ornamental tortoiseshell. This is illegal, although there are thriving black markets, particularly in East Asia, and the hawksbill turtle is classed as critically endangered. Adult hawksbills are around a metre long, and you can spot their tracks in the sand as they are asymmetrical, unlike those of the leatherback and green turtles with whom they share nesting beaches. Incredibly, scientists have only just discovered that hawksbills are biofluorescent – meaning their shells glow shades of green, red and orange when a light is shone on them at night. This is only reptile which is known to have this trait.

Olive ridley

These are the world’s smallest sea turtles, but they are responsible for one of the most impressive turtle sights – the arribada in Costa Rica. In the last week before the new moon, over the course of four or five days, thousands – sometimes hundreds of thousands – of olive ridley turtles crawl ashore simultaneously to lay their eggs on the Pacific beach at Ostional. This takes place during the rainy months of August to December, when this remote region is at its least accessible; though that hasn’t stopped it becoming a huge tourist attraction in the last couple of years. People are arriving literally by the busload, crowding the beaches, leaving little space for the turtles, trampling over nests and causing huge problems – the most responsible way to support the turtles in Ostional is, sadly, by not going. But we think that witnessing a turtle nesting on an empty beach elsewhere in Costa Rica is a far more magical experience anyway.


These marine giants are the world’s largest, reaching an impressive two metres in length and weighing up to 900kg. But size isn’t the only leatherback superlative; they have the widest range of any sea turtle, being found everywhere in the world except the Arctic and Antarctic. This is partly due to their ability to generate and maintain body heat, unlike most other reptiles. The leatherback swims further than any other sea turtle during its annual migrations between its feeding and breeding grounds – on average around 6,000km. They also dive deeper, reaching depths of up to 1,280m and staying beneath the surface for up to 85 minutes.
The lack of valuable shell does not deter poachers, their meat is still in demand – as are their eggs. They frequently get caught in fishing nets and coastal development has destroyed many nesting grounds; as every female returns to the beach she was born on to lay her own eggs, losing a beach can mean that dozens of females are no longer able to nest. In addition, plastic waste can resemble jellyfish – the leatherback’s favourite food. Ingesting large amounts of this (some dead turtles have been found with close to 5kg in their stomachs) will kill them. As a result, leatherback turtles are classified endangered.

Green Turtle

The green turtle is, appropriately, a herbivore, living entirely off seagrass and algae. Yet despite being the only turtle to have a veggie diet, it is the second largest species after the mighty leatherback, reaching lengths of around 1.5m and weighing up to 190kg. Their smooth shells are dark brown, olive or black in colour, though their name comes from the greenish tinge of their body fat. Green turtles nest throughout the tropics, and even reach the Mediterranean, with a nesting ground in Turkey – although this small population is classified as critically endangered.
Photo credits: [Leatherback turtle: Alastair Rae] [Olive Ridley: Oyster Worldwide] [Hawksbill: U.S. Fish and Wildlife Service Southeast Region] [Green Turtle: Jim Trodel]
Written by Vicki Brown
Turtle conservation in Costa Rica

Turtle conservation in Costa Rica

Help research and protect sea turtles and other wildlife

From £695 7 Days ex flights
Peloponnese turtle conservation holiday, Greece

Peloponnese turtle conservation vacation, Greece

Sea turtle volunteering on stunning Greek beaches

From 850 9 Days ex flights
Family volunteering with turtles in Costa Rica

Family volunteering with turtles in Costa Rica

Family turtle conservation volunteering in Costa Rica

From £749 7 Days ex flights
Seychelles Island conservation vacation

Seychelles Island conservation vacation

Volunteer on an exclusive island paradise in the Seychelles!

From US $2800 4 Weeks ex flights
Costa Rica turtle conservation experience

Costa Rica turtle conservation experience

Help protect turtles by volunteering in Costa Rica!

From £640 8 Days ex flights
Turtle conservation in Greece

Turtle conservation in Greece

Help save sea turtles from extinction

From £649 14 Days ex flights
Volunteer with turtles in Costa Rica

Volunteer with turtles in Costa Rica

Protect nesting turtles on Costa Rica's beautiful beaches

From £989 7 Days ex flights
Photo credits: [Page banner: Isabella Jusková]