7 Types of Sea Turtles: Photos and Fun Facts

Sea turtles are fascinating marine reptiles composed of two families and seven sea turtle species. These turtles are well-adapted to the ocean and have several unique adaptations that set them apart from their land and freshwater turtle counterparts.

For one, they have paddle-like flippers instead of limbs. They have streamlined bodies (to reduce drag) as opposed to the doomed-shaped shells of their terrestrial counterparts. To excrete salt, they possess specialized salt glands found near their eyes. They also can't retract their heads back to their shells.

Did you also know that sea turtles travel thousands of miles all throughout the year to feed, breed, and lay their eggs? They swim along the ocean currents during these long travels. Interestingly, the mothers return to the exact same beach where they were born to lay eggs. Sea turtles spend most of their lives in the ocean and only visit the land during nesting season.

In this article, we'll discuss the seven species of sea turtle, their descriptions, habitats, behavior, and some interesting facts.

Related Reads: Types of Turtles, Sea Turtle Facts

7 Types of Sea Turtles

Quick links to our list of sea turtle species:

Dermochelyidae 

The Dermochelyidae family consists of only one species: the Leatherback Sea Turtle. Unlike the Cheloniidae family, this family has a unique physical appearance. They lack the bony shell present in other turtle species and have a leathery, flexible carapace with prominent ridges. Furthermore, they don't have scales.

They can live in both cold and warm waters of some ocean regions. They are known to undertake extensive migrations between nesting beaches and foraging areas.

1. Leatherback Sea Turtles (Dermochelys coriacea)

Fun Fact: Did you know that the Leatherback Sea Turtle holds the record for being the largest turtle species in the world? These incredible creatures can grow up to 7 feet long and weigh over 2,000 pounds!

The Leatherback Sea Turtle (Dermochelys coriacea) is the only extant species of the Dermochelyidae family. It is known as the largest of all sea turtle species. An adult Leatherback Sea Turtle can reach an impressive average length of 6 to 7 feet and weigh between 550 to 2000 pounds.

Their hatchlings are also relatively large compared to other species and can typically measure around 2 to 3 inches (5 to 8 centimeters) in carapace length. They are also incredible deep-sea divers, descending to depths of over 4,000 feet to find their main prey, the jellyfish. They have specialized papillae in their mouths that help them capture and consume these gelatinous creatures.

Additionally, Leatherback Turtles nest on tropical and subtropical beaches around the world. A female Leatherback can lay 85 to 95 eggs in her sea turtle nest. Sea turtles hatch around two months. This sea turtle species have also the longest migrations (10,000 miles annually), moving from foraging grounds to nesting beaches.

The Leatherback Sea Turtles gained Vulnerable status from the International Union for Conservation of Nature Red List. Like many other marine turtle species, they face many threats, such as entanglement in fishing gear, accidental ingestion of plastic debris, and sea turtle hunting.

Cheloniidae

The Cheloniidae family includes the other six sea turtle species. Species from this family have scales and hard shells. These six species found in US waters are listed as endangered under the Endangered Species Act and included in the IUCN Red List, where their status ranges from Vulnerable to Critically Endangered.

2. Loggerhead Sea Turtle (Caretta caretta)

Fun Fact: Did you know that the Loggerhead Sea Turtle got its name from its large head, which is quite massive compared to other species? The Loggerhead's head is so strong that it can easily crush the shells of its favorite prey, the crabs and clams!

The Loggerhead Sea Turtle scientific name is Caretta caretta. This species is one of the largest sea turtles thanks to its enormous head. They have a reddish-brown heart-shaped top shell (Carapace) and a yellow-brown bottom shell (Plastron). Adult sea turtles can grow up to around 2.5 to 3.5 feet (75 to 110cm) in shell length and weigh between 200 to 350 pounds (90 to 160kg).

The Loggerhead Sea Turtle can also be found in the Atlantic, Pacific, and Indian Oceans. They are the most common sea turtles in America. They also migrate long distances, sometimes crossing entire ocean basins. Like other species, these sea turtles rely on ocean currents to migrate.

They consume a variety of marine invertebrates, such as crabs, jellyfish, shrimp, and other mollusks. However, they may also eat plant material like algae. Just like other turtles, Loggerheads have a unique reproductive process.

Female sea turtles have a remarkable nesting behavior known as "natal homing." After reaching maturity (around 35 years), they return to the exact beach where they were born to lay up to 500 eggs. They live long and can reach an age of 70-80 years.

Sadly, the Loggerheads are classified as Vulnerable species by the International Union for Conservation of Nature Red List due to threats to sea turtle populations such as habitat destruction, pollution, accidental capture in fishing, and climate change, which impact the nesting beaches.

3. Green Sea Turtle (Chelonia mydas)

Fun Fact: Did you know that the Green Sea Turtle is not named after its color? They got their name after their greenish fat due to their herbivorous diet of seagrass and algae.

The Green Sea Turtle's scientific name is Chelonia mydas. The name "green" of this species does not refer to the sea turtle's shell but to the greenish color of their fat and cartilage. Their carapace is typically brown, black, or olive, and their skin is yellowish. In the Eastern Pacific, some green turtles have relatively darker shells, earning the name "Black Turtles.”

Interestingly, Green Sea Turtles are the only sea turtle species that are exclusive herbivores. They eat seagrasses and algae, which help maintain healthy coral reefs. These marine turtles have serrated jaws that allow them to munch their fibrous diet.

The adult Green Turtles are giant; males can grow 3 to 3.5 feet in carapace length, while females can reach 4 to 5 feet and weigh between 200 to 500 pounds. They are the biggest among the hard-shelled sea turtles. They live in the waters of the Atlantic, Pacific, and Indian Oceans and the Mediterranean Sea.

Females become sexually mature at the age of 25 to 35 years. Females can lay about 100 eggs per nest. Green sea turtle hatchlings usually emerge from the nest at night when there are fewer predators. However, natural predators (like sea birds) can still kill them, and artificial lighting can disorient them (baby turtles use moonlight to locate the ocean).

Green Sea Turtles can live 70 years or more. However, they are endangered as they are heavily hunted for meat and eggs. They are also in the Endangered Species Act, and killing them is strictly prohibited in the US.

4. Hawksbill Sea Turtle (Eretmochelys imbricata)

Fun Fact: Did you know that the Hawksbill Sea Turtle got their name from their beak-like mouth? Their unique mouths are perfect for eating their favorite meal- sponges.

Hawksbill Sea Turtle scientific name is Eretmochelys imbricata. They have a distinct appearance with a small to medium-sized body and a relatively narrow, pointed beak-like mouth. They have two pairs of prefrontal scales on their head, differentiating them from most sea turtles.

Hawksbill sea turtles use their narrow beaks to reach into crevices and cracks in coral reefs to extract sponges as their primary food source. In addition to sponges, they consume other marine invertebrates, algae, and small fish.

Their sea turtle shells (commonly referred to as tortoise shells) are highly coveted by the black market due to their peculiar beauty. The illegal trade almost drove these species to extinction. The colors of their shells are a combination of shades of amber, orange, red, yellow, black, and brown.

Their nesting season depends on the region but is usually during the warmer months. They lay around 100 to 150 eggs in each nest and may nest multiple times. Their incubation period may last approximately 60 to 80 days.

According to the International Union for Conservation of Nature Red List, the Hawksbill Turtles are critically endangered. Hunting, habitat destruction, plastic pollution, improper fishing methods, and climate change contribute to their declining population. Organizations are protecting their nesting sites to ensure their survival.

5. Kemp's Ridley Sea Turtle (Lepidochelys kempii)

Fun Fact: Did you know that Kemp's Ridley Sea Turtles are known for their synchronized nesting behavior? These fantastic creatures gather in large groups, known as arribadas, to lay their eggs on the same beach simultaneously!

Kemp's Ridley Sea Turtle is scientifically known as Lepidochelys kempii. Their name came after the fisherman Richard M. Kemp, who was the first to submit the species for identification. They are the smallest sea turtle species². They have a heart-shaped carapace that is olive-gray in color, and their limbs are paddle-shaped for swimming. As omnivorous, their diet includes crabs, shrimp, and other marine creatures.

Kemp's Ridley Sea Turtle nests are all over the Gulf of Mexico and the western North Atlantic Ocean. 95% of the nesting grounds are in Tamaulipas, Mexico. They have a unique nesting behavior called "arribada," where large groups of females come ashore to nest. The arribada occurs only from April to July.

This sea turtle's age can range from a minimum of 30 years. However, Kemp's Ridley Sea Turtle is one of the world's most critically endangered species. Accidental capture in fishing gear, turtle hunting, and degradation of nesting habitats are some of their major threats.

6. Olive Ridley Sea Turtle (Lepidochelys olivacea)

Fun Fact: Did you know that the Olive Ridley Sea Turtle is named after their Olive Green shells?

The Olive Ridley Sea Turtle is the second smallest sea turtle. They have a slightly larger carapace length than Kemp's Ridleys, ranging from 60 to 70 centimeters. Olive Ridley Sea Turtle is omnivorous and eats algae, seaweed, crabs, and other marine invertebrates. They are also the most abundant sea turtle species in the world.

While each arribada event involves thousands of olive ridley females, they often lay their eggs in synchronized rhythms. Their eggs have a unique greenish hue, thanks to their plant diet.

Olive ridley turtles are skilled navigators and undertake long-distance migrations, traveling thousands of kilometers between nesting and foraging grounds. Despite their abundance, Olive Ridley Sea Turtles are classified as vulnerable species by the International Union for Conservation of Nature Red List.

7. Flatback Sea Turtle (Natator depressus)

Fun Fact: Did you know that the Flatback Sea Turtle is the only sea turtle species endemic to Australia? This means that it is found nowhere else in the world!

The Flatback Sea Turtle's scientific name is Natator depressus, also known as the Australian Flatback Sea Turtle¹ or, more simply, the Flatback Turtle. They mainly reside in the waters of northern Australia and southern Papua New Guinea.

As their name suggests, the Flatback Sea Turtle has a unique flat-shaped carapace. Unlike other sea turtle species, its carapace lacks a prominent arch or keel, which gives them a distinct appearance. They are relatively smaller. Adult flatbacks typically have a carapace length of about 70 to 100 centimeters and weigh around 70 to 90 kilograms.

They are omnivores whose diet consists of algae, sea grass, and marine invertebrates such as sea cucumbers, soft corals, and other small marine organisms in coastal waters.

Additionally, they lay their eggs in shallow nests on Australian sandy beaches. However, this species of sea turtles has the smallest distribution. Additionally, many baby sea turtles die during the treacherous crawl from the nest to the sea, where they're at risk of predation by birds, foxes, crabs, and raccoons.

Flatback Sea Turtles have Data Deficient status on the International Union for Conservation of Nature Red List. This means that researchers must collect more data to assess their conservation status accurately. However, they face threats similar to other sea turtles.