Sea turtles are fascinating creatures. Check out this list of seven things you might not already know about the much loved marine reptiles, from NOAA Fisheries.
Front view of a striped sea turtle underwater.
A hawksbill sea turtle in western Maui, Hawai’i. Image via Don McLeish/ NOAA Fisheries.
1. In many parts of the world, hawksbills are threatened by hunting for their beautiful shell
Also known as “tortoise shell,” it is used by craftspeople to create many types of jewelry and trinkets. The historical hunting and killing of hawksbills for their shell nearly drove the species to extinction. Today, the Convention on International Trade of Endangered Species forbids the trade of any turtle products on the international market, including hawksbill tortoise shell.
Illegal hunting and trade continue to threaten the species in many parts of the world. Learn more about the hawksbill turtle.
Closeup of small sea turtle with disproportionatately large flippers on a beach.
Leatherback turtle hatchling on beach. Image via NOAA Fisheries.
3. Diet varies depending on the species
Loggerheads are carnivores, only occasionally consuming plant material. Juveniles and adults in coastal waters eat mostly bottom dwelling invertebrates such as whelks, other mollusks, horseshoe crabs, and other crabs. Their powerful jaws are designed to crush their prey. Hawksbill turtles use their sharp beak to reach into small holes and crevices in coral reefs to find their preferred food source, sponges.
Leatherbacks have spiny “papillae” lining their mouth and esophagus. These spines help them trap and consume their main prey species, jellyfish. Green sea turtles are unique among sea turtles in that they are primarily herbivores, eating mostly seagrasses and algae. This diet is what gives their cartilage and fat a greenish color (not their shells), which is where their name comes from.
Turtle swimming straight toward camera in blue water.
Loggerhead turtle. Image via Wikimedia Commons.
4. Ridleys have unique nesting habits
The two species of ridley sea turtles – Kemp’s ridleys and the olive ridleys – primarily nest in groups. This phenomenon is called an “arribada,” which is Spanish for “arrival.” Hundreds to thousands of turtles come ashore across several hours or days and lay thousands to hundreds of thousands of eggs. This nesting behavior is designed to swamp natural predators which ensures that enough eggs and hatchlings will survive to keep the population stable.
Kemp’s ridley and olive ridleys are the two smallest species of sea turtles. Learn more about the olive ridley turtle and the Kemp’s ridley turtle.
Lots of sea turtles on a dark beach with sea in background.
Olive ridley sea turtles nesting en masse during an “arribada” on Playa Ostional, Costa Rica, on September 9, 2004. Image via Michael Jensen/ NOAA Fisheries.
5. All sea turtles are threatened by pollution and marine debris
Pollution of nearshore and offshore marine habitats threatens all sea turtles and degrades their habitats. The Deepwater Horizon oil spill in 2010 was the largest offshore oil spill in U.S. history and affected all life stages and species of sea turtles inhabiting the Gulf of Mexico. Ingestion of marine debris is another threat to all species of sea turtles.
Turtles may ingest marine debris such as fishing line, balloons, plastic bags, floating tar or oil, and other materials they can mistake for food. Microplastics are an increasing threat to sea turtles, especially young turtles living and feeding near the surface.
A person on a boat holding a sea turtle covered in oil.
Kemp’s Ridley sea turtle covered in oil. Image via Florida Fish and Wildlife Commission/ NOAA Fisheries.
6. Sea turtles lay about 100 eggs per nest
During the nesting season, green turtles will nest every two weeks over several months and lay four or more nests before leaving the nesting area and returning to their foraging grounds. Green turtles are a long-lived species and can live for 70 years or more. Female green turtles reach maturity at 25 to 35 years and will continue to nest for 30 years or more.
Every two to five years they undertake reproductive migrations and return to nest on a beach in the general area where they hatched decades earlier. Over her lifetime, a female will produce thousands of eggs and hatchlings. Learn more about the green turtle. Watch baby sea turtles hatch and head toward the sea.
7. Sand temperature is very important
The sex of sea turtles, like many other turtles, is determined by the temperature in the nest. Cooler incubation temperatures produce primarily male hatchlings and warmer incubation temperatures produce primarily female hatchlings. Temperatures that fluctuate between the two extremes will produce a mix of male and female hatchlings. Watch the video above to learn about research on alarming trends as global temperatures rise, and fewer male turtles are hatching from the nesting beaches.