Turtles have existed since the age of the dinosaurs. They are robust reptiles that live in most of the planets oceans! The oldest recorded turtle is a 120 million year ago fossil that is six-foot long. Sea turtle species have bony plates along their shell that are known as scutes and exist on other reptiles like crocodiles.
These reptiles are classified into two groups that are differentiated based on having a soft or hard shell. All the types of sea turtles are semi-aquatic reptiles that spend most of their lives in the water but come onto land to lay their eggs. They are fantastic swimmers and can hold their breath for a very long time!
1. Green Sea Turtle
Green sea turtles are some three to four feet long, putting them amongst the largest of all the hard-shelled sea turtle species. They weigh around 300 to 400 pounds and have olive-colored shells and white-to-yellow undersides. They can be distinguished by two scales found in between their eyes and the serrated beak on their lower jaw.
Their shell is divided into geometrical shapes by five scutes that run down their shell, with another four scutes on either side. They are herbivores and feed entirely on seagrasses and different algae species. Their diet is responsible for the greenish color of their body fat, that gives them their name.
Green sea turtles are found in the Indian, Pacific, and Atlantic Ocean in tropical and subtropical regions. They nest in 80 countries, including Puerto Rico, Hawaii, and the US. However, they have been spotted off the shores of more than 140 countries worldwide! These sea turtles nest at night when there is less chance of predation and return to the sea after laying their eggs.
2. Loggerhead Sea Turtle
These hard-shelled turtles are about 3.5 feet long, and often cited as the largest hard-shell sea turtle. They weigh some 253 pounds and were named after their large heads! They have white skin with brown scales, and a Brownish-red shell.
Loggerhead turtles are carnivorous, feeding on invertebrates they forage off the ocean floor and then crush up with their mighty jaws. They digest their prey’s shells, and their secretions fall back to the seabed and become a source of calcium for other aquatic species, thus these turtles are essential members of their ecosystems and make it into the category of keystone species.
They live in all the major subtropical and temperate regions of the world’s oceans and travel long distances along their migration routes. Loggerhead sea turtles have even been spotted in inland water reserves! They hold the record for the longest underwater turtle dive, holding their breaths for more than 10 hours.
3. Kemp’s Ridley Sea Turtle
These small turtles are just two feet long. They have black shells and scaly, white skin with black markings. The species was first identified by Richard Kemp in Key West, Florida and later named after him. They can weigh up to 100 pounds once they reach adulthood.
Kemp’s ridley sea turtles are omnivores, feeding on both plant and animal matter. However, most of their diet is made up of shellfish like crab. However, they even eat jellyfish! Just a small proportion of their diet consists of seaweed and sargassum that they nibble on with their little beaks.
The kemp’s ridley turtle is mostly found in the Gulf of Mexico, although there have been occasional sightings in the North Atlantic Ocean too. These little sea turtles can live up to 50 years in the wild and are sadly now critically endangered. There are on-going conservation efforts attempting to restore their once thriving populations.
4. Olive Ridley Sea Turtle
These small sea turtles are around two to 2.5 feet long, but their size varies slightly depending on their geographical location. They weigh a maximum of 100 pounds and were named the olive ridley sea turtle because of the color of their shell. The turtle’s heart shaped carapace has between five to nine pairs of scutes on it.
They are found in the warm tropical waters of all the major oceans: the Pacific, Indian, and Atlantic. Olive ridley turtles mostly inhabit open waters but have been spotted anywhere between up to 2,500 miles offshore and close to land in the sea’s coastal regions.
These turtles often return to the beach where they hatched to lay their own eggs. Females gather in their hundreds and thousands to lay their eggs, a phenomenon known as the “arribada”. They can somewhere between 30-50 years in the wild.
5. Hawksbill Sea Turtle
Hawkbill sea turtles are around two to three feet long and have a hard shell. They were named after their bird-like beak. Another distinguishing feature of this turtle species is that their shell is sometimes covered in algae, giving it a bright green coloration.
They feed on sponges that they forage amongst coral reefs, using their slender heads and sharp beaks to get to food hidden in this intricate landscape. It is estimated they consume nearly 1,000 pounds of sponges each year. They’re essential gardeners for coral reefs, picking out toxic sponges that would otherwise takeover. It is thought that the coral reef’s ecosystem wouldn’t thrive without these turtles.
They can weigh anywhere between 100-200 pounds and live in tropical and subtropical oceans around the world, normally near the shore but also further out in the open ocean. Though they tend to stick near to coral reefs where they can easily find their favorite foods!
6. Flatback Sea Turtle
These sea turtles grow to 2.5 to three foot in adulthood and weigh up to 220 pounds. They are distinguished by their unique shell, that is less rounded than those of other sea turtle species, giving them their name.
They live in coastal waters around Australia and Papua New Guinea, and don’t travel very far during their annual migrations like other sea turtle species. In fact, flatback populations have the smallest geographical distribution of all seven sea turtles, attributed to their limited habitat range and short migration routes.
Curiously, female flatbacks only nest on beaches in Australia. They lay their eggs and burry their nests before getting back into the ocean. There’s not much mothers can do to protect the vulnerable eggs and hatchlings. This turtle species is omnivorous and individuals primarily feed on soft-bodied animals, such as jellyfish and sea cucumbers, as well as soft corals.
7. Leatherback Sea Turtle
The leatherback sea turtle is the largest turtle of them all! They can grow as long as seven feet, making them bigger than humans! Their shell has a dark gray to bluish black coloration, and they are covered in patchy white or pink spots, giving them a speckled appearance.
These enormous sea turtles can weigh up to 2,000 pounds and live for 45 years in the wild. They are great divers that can reach depths of 4,200 feet in search of food, holding their breath for nearly three hours!
Unlike other sea turtles, they have a soft shell that has a leather-like texture. They are found in tropical and temperate waters across the Atlantic, Pacific and Indian Ocean. Leatherbacks have the largest geographical distribution of all seven species of sea turtle, covering distances of 3,700 miles each time they between their breeding and feeding grounds.