7 Types of Sea Turtles and Their Characteristics

Sea turtles belong to two main families: Cheloniidae and Dermochelyidae. Within these groups, we find the green turtle, loggerhead turtle, olive ridley turtle, hawksbill turtle, flatback turtle, Kemp’s ridley turtle, and leatherback turtle.

They are among the most fascinating reptiles of the oceans, with millions of years of evolutionary history. If you are interested in these creatures, keep reading to discover the 7 species of sea turtles, their main traits, and the threats they face today.

General Characteristics of Sea Turtles

Before exploring each species individually, let’s look at what sea turtles have in common:

• They are marine reptiles.

• Prefer tropical and subtropical waters.

• Usually inhabit shallow coastal areas but can dive into deep waters for food.

• Possess both an internal and external skeleton (carapace + plastron).

• The lower shell (belly side) is called the plastron.

• Have eyelids and excellent underwater hearing, able to detect tiny vibrations.

• They lack teeth but have powerful jaws, and some species have serrated beak-like edges to cut food.

• Possess an acute sense of smell both underwater and on land.

• Hatchlings emerge from eggs buried in sandy beaches after 30–60 days of incubation.

• Baby turtles instinctively head straight to the sea after hatching, but most fall prey to predators.

• Only females return to beaches to nest, while males remain in the ocean for life.

• Mothers do not return to check nests or care for hatchlings.

• Gender can be distinguished by tails: males have long tails extending past the rear flippers; females’ tails are short.

• Diet varies: some are herbivorous, some carnivorous, others omnivorous.

• Main threats include plastic pollution (especially bags mistaken for jellyfish), large fish, sharks, toothed whales (orcas, belugas, sperm whales), and of course, humans.

1. Green Turtle (Chelonia mydas)

• Distribution: Tropical and subtropical coasts worldwide.

• Size: Up to 1.6 m in length, ~230 kg in weight.

• Appearance: Oval carapace, greenish-brown on top, white on the underside. Each flipper has a visible claw.

• Habits: Usually solitary but may form feeding groups in seagrass beds.

• Migration: Travel thousands of kilometers between feeding grounds and nesting beaches (Costa Rica, Venezuela, Brazil). Females lay 85–145 eggs per clutch, up to five clutches per season.

• Conservation status: Endangered (IUCN).

2. Loggerhead Turtle (Caretta caretta)

• Distribution: Atlantic, Pacific, Indian Oceans, and the Mediterranean Sea.

• Size: Adults ~90 cm, 135 kg; maximum 1.2 m, 180 kg. Lifespan 40–70 years.

• Appearance: Large head, reddish-brown carapace often covered with barnacles and other epibionts.

• Habits: Highly migratory, nesting mostly in the Caribbean.

• Diet: Omnivorous, feeding on benthic invertebrates, fish, algae, even insects.

• Conservation status: Endangered (IUCN).

3. Olive Ridley Turtle (Lepidochelys olivacea)

• Distribution: Tropical and subtropical oceans worldwide (except the North Atlantic).

• Size: The smallest sea turtle, up to 0.7 m and 50 kg. Olive-colored carapace.

• Habits: Gregarious, often found in coastal waters.

• Diet: Marine invertebrates and vegetation.

• Reproduction: Known for mass nesting events called “arribadas”, where up to 100,000 females lay eggs simultaneously.

• Conservation status: Vulnerable (IUCN).

4. Hawksbill Turtle (Eretmochelys imbricata)

• Distribution: Tropical Atlantic, Pacific, and Indian Oceans.

• Size & Traits: Colorful carapace with brown, reddish, and yellow patterns.

• Diet: Specializes in eating sponges, but also feeds on algae, anemones, and jellyfish.

• Threats: Hunted for its decorative shell (“tortoiseshell”) used in jewelry and crafts.

• Conservation status: Critically Endangered (IUCN).

5. Flatback Turtle (Natator depressus)

• Distribution: Endemic to northern Australia, the only place where it breeds.

• Appearance: Flattened, grey-green dorsal shell; creamy underside.

• Habits: Prefers shallow coastal waters and coral reefs.

• Diet: Benthic invertebrates, fish, and occasionally algae.

• Conservation status: Threatened.

6. Kemp’s Ridley Turtle (Lepidochelys kempii)

• Distribution: Western Atlantic, from Newfoundland to Venezuela, including the Gulf of Mexico.

• Size: Among the smallest species, ~0.9 m length, ~45 kg weight.

• Appearance: Grey-green carapace, yellowish underside.

• Diet: Crabs, mollusks, jellyfish, sea urchins, and algae.

• Conservation status: Critically Endangered (IUCN).

7. Leatherback Turtle (Dermochelys coriacea)

• Distribution: Found in nearly all oceans; only member of the Dermochelyidae family.

• Size: Largest of all sea turtles, up to 2.5 m long and 600 kg on average (recorded cases up to 900 kg).

• Traits: Lacks hard plates on the carapace; instead covered with thick, leathery skin with white spots.

• Habits: Deep divers, tolerate colder waters.

• Diet: Mainly jellyfish, but often mistake plastic for prey, leading to suffocation or intestinal blockages.

• Conservation status: Critically Endangered (IUCN).

Conservation Status of Sea Turtles

All 7 species of sea turtles are at risk:

• Green Turtle – Endangered

• Loggerhead Turtle – Endangered

• Olive Ridley Turtle – Vulnerable

• Hawksbill Turtle – Critically Endangered

• Flatback Turtle – Threatened

• Kemp’s Ridley Turtle – Critically Endangered

• Leatherback Turtle – Critically Endangered

Main Threats

• Climate change (affects nesting beaches and hatchling sex ratios).

• Marine pollution (especially plastics).

• Habitat destruction (coastal development and tourism).

• Bycatch in fisheries.

• Illegal hunting (for meat, shells, eggs).

Conclusion

Sea turtles are not only charismatic reptiles but also key species for ocean ecosystems. Protecting them means protecting the balance of marine food webs and the health of our oceans. By reducing plastic waste, conserving nesting beaches, regulating fisheries, and fighting illegal trade, we can give these ancient ocean travelers a chance to survive.

animal tags： turtles