Sea Turtle FAQ (Frequently Asked Questions)

Today, there are seven recognized species of sea turtles in the world, divided into two main groups: the leathery-shelled sea turtles (Dermochelidae) and the hard-shelled sea turtles (Cheloniidae).
Among the Leatherbacks, only a single species has survived to the present day: the Leatherback turtle (Dermochelys coriacea). In contrast, there are six species of hard-shelled sea turtles, including the loggerhead sea turtle (Caretta caretta), the olive ridley sea turtle (Lepidochelys olivacea), the Atlantic ridley sea turtle (Lepidochelys kempii), the hawksbill sea turtle (Eretmochelys imbricata), the flatback sea turtle (Natator depressus), and the green sea turtle (Chelonia mydas).
Sometimes, an eighth species is mentioned — the Black sea turtle of the eastern Pacific. However, it is now considered a subspecies of the Green sea turtle. In the past, there was also a third group, the Protostegidae, which included the largest known sea turtle, Archelon ischyros, reaching lengths of up to 5 meters.

Sea turtles have existed for at least 110 million years. Their exact evolutionary age is debated, but fossil evidence shows that the last common ancestor of modern leatherback turtles and hard-shelled sea turtles already lived in the Early Cretaceous period.
Because sea turtles have changed so little over millions of years, they are often called the “dinosaurs of the sea.” Although scientific estimates vary, fossils clearly prove their ancient origin and remarkable evolutionary success.

Sea turtles can be found in all tropical and subtropical oceans around the world. Leatherback turtles are even known to venture into colder waters, such as off the coast of Scotland.
Most sea turtle species are widely distributed across their preferred latitudes. However, there are two notable exceptions: the Kemp’s ridley turtle, which lives almost exclusively in the Gulf of Mexico, and the flatback turtle, which is restricted to the northern coastal waters of Australia and southern New Guinea.
While leatherback turtles and some loggerhead turtles are highly adapted to life in the high seas, most other sea turtle species stay closer to the coast or continental shelves, crossing the high seas mainly during their long-distance migrations.

The largest species of sea turtle is the leatherback turtle (Dermochelys coriacea), which can grow up to 2 meters (6.5 feet) long and weigh almost 1 ton (2,000 pounds). Their powerful front flippers can reach an impressive span of up to 2.7 meters (9 feet), making them excellent long-distance swimmers.
Among the hard-shelled sea turtles, the green sea turtle (Chelonia mydas) is the largest, reaching lengths of up to 1.2 meters (4 feet) and weighing as much as 225 kilograms (500 pounds).

Depending on the species, sea turtles can live at least 60 years or more, and some individuals are believed to reach an age of over 90 years. However, the natural lifespan of sea turtles in the wild is still not precisely known, since no turtle has ever been tracked continuously from birth to natural death.
Recent research from South Carolina even documented a grandmother nesting at the same time as her granddaughter. Considering that loggerhead turtles (Caretta caretta) take around 30 years to reach sexual maturity, these findings suggest that female sea turtles can still reproduce well into their nineties.

Sea turtles reach sexual maturity between the ages of about 7 and 40 years, depending on the species. The estimated age of maturity not only differs between species, but also between populations of the same species.
Leatherback turtles: 7–13 years
Olive ridley and Kemp’s ridley turtles: 11–16 years
Hawksbill turtles: 20–25 years
Loggerhead turtles: 25–35 years
Green sea turtles: 26–40 years
→  Green turtles take the longest to mature because their diet is mainly seagrass and algae, while the more carnivorous species generally mature earlier.

The age at which sea turtles reach sexual maturity is often linked to their carapace size:
Hawksbill turtles: 69–78 cm
Loggerhead turtles: 50–87 cm
Leatherback turtles: 145–160 cm
Even after reaching sexual maturity, sea turtles continue to grow, although at a much slower rate.

Sea turtles have diverse diets depending on their species, ranging from jellyfish and coral to seagrass.
– Australian flatback sea turtles: Primarily carnivorous, feeding in shallow waters on soft seabeds.
– Green sea turtles: vegetarian diet as adults, consuming seagrass and algae; hatchlings are omnivorous, eating jellyfish, snails, crabs, and shrimp.
– Hawksbill sea turtles: Use their sharp, bird-like beak to feed on soft corals, sea anemones, and marine sponges.
– Kemp’s ridley sea turtles: Juveniles are omnivorous, eating algae, crabs, and snails; adults primarily eat crustaceans, fish, mollusks, squid, and jellyfish.
– Leatherback turtles: Mainly feed on jellyfish.
– Loggerhead turtles: Primarily consume hard-shelled organisms such as lobsters, crustaceans, and fish.
– Olive Ridley Turtle (Lepidochelys olivacea): Omnivorous, eating mostly jellyfish, snails, crabs, and shrimp, but also algae and seaweed.

Male sea turtles have noticeably longer and thicker tails than females. In addition, males possess elongated claws on their front flippers. These specialized claws help them grip the female’s dorsal carapace securely during mating.

Unlike in many animals, the sex of sea turtles is not determined by chromosomes. Instead, it is set during embryonic development based on the average incubation temperature in the nest. At the pivotal temperature of approximately 29.5 °C (85,1°F), roughly equal numbers of males and females are produced. Higher temperatures result in a greater proportion of females, while lower temperatures produce more males.

During the nesting season, sea turtles typically lay between six and ten clutches. Some green sea turtles can even lay up to 12 clutches per season.
Each clutch contains between 80 and 180 eggs, depending on the species and size of the turtle. The largest sea turtle—the leatherback—lays around 110 eggs per clutch. Hawksbill turtles produce the largest clutches, with up to 140–160 eggs in a single nest!

Sea turtles have an incredible ability: even after decades, they can return to the very beach where they were born to lay their eggs.
Scientists are still studying exactly how they navigate, but it’s believed that they rely on sensing and remembering the unique strength and direction of the Earth’s magnetic field at their birthplace.

The incubation period from egg-laying to hatching averages around 60 days. However, depending on the species, population, and average nest temperature, this duration can vary by several days.

Mother turtles give their offspring the best start in life by carefully selecting the nesting site, digging the nest, and concealing it well. After that, the eggs—and later the newly hatched turtles—are on their own.

Population biology calculations suggest that out of approximately 1,000 hatchlings, only one reaches adulthood and returns to the beach of its birth to reproduce. This low survival rate is offset by the large number of offspring produced.

Along the coasts and in their feeding grounds, juvenile sea turtles can be observed up to roughly the size of a dinner plate, but smaller individuals are rarely seen. For decades, the developmental stage from hatching to this “dinner plate” size remained a mystery to science, commonly referred to as the “lost years.” Only relatively recently has it become clear that these tiny hatchlings spend their early years in the open ocean. During this period, they often drift alongside floating debris and are passively carried by ocean currents.

Sea turtle eggs, hatchlings, and juveniles face numerous natural predators both on land and in the ocean.
The most common predators include:
On land: fire ants, crabs, monitor lizards and other large reptiles, birds, dogs, raccoons, wild pigs, and coyotes
In the water: dolphins, sharks, and many carnivorous fish species such as snappers, groupers, and barracudas

Humans have significantly reduced sea turtle populations through numerous direct and indirect impacts, pushing some species and populations to the brink of extinction. In the past, hunting turtles and the harvesting of turtle eggs were the main causes of decline. Today, however, indirect threats play an even greater role. These include bycatch in fisheries, habitat destruction, marine and coastal pollution, and the growing effects of climate change.

Here you can read more about threats and conservation of sea turtles

Everyone can help reduce the human impact on marine ecosystems by living more sustainably. As a tourist in sea turtle habitats – especially on nesting beaches – it is crucial to behave responsibly and minimize disturbance to the animals. Products made from sea turtles, particularly tortoiseshell, should never be purchased, even though they may still be found in some local markets or online.
Direct support is also possible through conservation organizations such as the Turtle Foundation. You can contribute by making a donation, adopting a sea turtle through a symbolic sponsorship, purchasing sustainable merchandise, or even joining us as a volunteer on Boa Vista. Every contribution makes a difference in ensuring the survival of these ancient marine reptiles.

No, sea turtles do not get high from eating jellyfish. This widespread myth originates from Pixar’s Finding Nemo, where the character Crush seems to behave as if he’s “permanently high.”
In reality, jellyfish are a natural and important part of the diet for several sea turtle species – for some, they are even a favorite food. The poison that make jellyfish painful and dangerous for humans have no effect on sea turtles, as their bodies are specially adapted to safely consume them.