Sea turtles are turtles that belong to the superfamily Chelonioidea. This includes the families Cheloniidae and Dermochelyidae.
Sea turtles are also known as marine turtles. They are called sea turtles because they live in the sea.
There are seven species of sea turtles these include olive ridley, Kemp’s ridley, loggerhead, leatherback, hawksbill, green, and flatback sea turtles.
The olive ridley is endemic to only the waters and beaches of the Australian continental shelf. The rest can be found in all the oceans of the world.
The leatherback sea turtle is also the only sea turtle endemic to subarctic waters and can be found as far north as Nova Scotia in northeastern Canada.
Below are some sea turtle facts:
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Sea Turtles Cannot Retract Into Their Shells
Unlike most turtles, sea turtles cannot retract or hide in their shells. Their bodies are adapted to swim swiftly and with ease.
As such, their shells are flatter and aerodynamic. The aerodynamic nature of their shells allows them to easily cut through the water. However, this means that they do not have enough space within their shells to retract into.
Interestingly, they have the same muscles as other turtles and as such can retract their heads, just not into their shells. The sea turtle isn’t the only turtle that cannot retract into its shells, freshwater softshell turtles such as the spiny softshell and the smooth softshell are also unable to retract into their shells.
Adult Sea Turtles Have Few Predators
Because of the massive size of adult sea turtles and their tough shells, adult sea turtles have a limited number of predators. Very few animals can successfully attack an adult sea turtle.
Known predators include crocodiles, large fish such as sharks, and octopuses. Big cats such as jaguars are also known to attack nesting females.
Humans are also known to hunt sea turtles and are the top killers of sea turtles. Adult sea turtles are hunted by humans for their shells and meat. Because of the endangered and threatened nature of all sea turtle species, the hunting of sea turtles is outlawed in many countries.
Sea turtles are also protected under Appendix I of the Convention on International Trade in Endangered Species (CITES). This prohibits the international trade of marine turtles, their body parts, and products made from their body parts. Sea turtles are also produced under US Federal law.
Most Sea Turtles Migrate Over Large Distances
Apart from the Australian flatback, sea turtles are known to migrate over long distances. The olive ridley is known to migrate from the subtropical seas to the tropical seas to mate and nest.
Tagged leatherbacks have been known to travel 20,000 km or 12,000 miles in 647 days. They generally travel from foraging habitats to nesting habitats.
Kemp’s ridley is also known to travel thousands of miles. The same can be said of the green turtle and the loggerhead.
The Australian flatback however does not migrate over long distances and is found almost exclusively in the waters of Australia. Some specimens have been found foraging in the waters of Papua New Guinea although there is no evidence to suggest that they nest there.
Every Sea Turtle Species Are Either Endangered Or Threatened
The wild population of sea turtles has been struggling in modern times. These are amongst the most endangered animals in the world.
There are many reasons for the fall in wild population numbers of sea turtles and this includes the degradation of the foraging and nesting habitats of the chelonians, the overharvesting for human consumption, and pollution of the sea through oil spills & the dumping of trash such as plastic in the sea.
The species listed as endangered on the IUCN Red List include the green turtle (Chelonia mydas).
Species listed as critically endangered on the IUCN Red List include the hawksbill (Eretmochelys imbricata) and the Kemp’s ridley (Lepidochelys kempii).
Species listed as vulnerable on the IUCN Red List include the loggerhead (Caretta caretta), the olive’s ridley (Lepidochelys olivacea), and the leatherback (Dermochelys coriacea).
The Australian flatback (Natator depressus) is considered to be endangered in Australia although they are listed as data deficient on the IUCN Red List.
Green Sea Turtles Do Not Have Green Shells Or Skin
Green sea turtles also commonly known as green turtle is not green in coloration.
In fact, another of its common names, black turtle or black sea turtle, better describes its coloration. This turtle is known as the green turtle or the green sea turtle because of the greenish coloration of its subdermal fat.
So what is the color of green turtles? When hatched, these chelonians are deep black in coloration but as they grow their coloration lightens. They are usually black to tan in color.
Green sea turtles may have algae growing on their shell which may give them a greenish coloration at times but this is due to the algae and is not actually the color of the turtle.
Green Sea Turtles Have Greenish Subdermal Fat Because Of Their Diet
Following up on the previous fact – why do green turtles have greenish-colored subdermal fat? The leading theory as to why green turtles have green fat is due to what they eat.
Adult sea turtles are herbivorous and feed on algae and seagrasses. Adult sea turtles are known to be one of the few animals in the ocean that actually feed on seagrass. The manatee is another animal known to feed on seagrass.
Interestingly, green turtles aren’t born herbivorous. As hatchlings and juveniles, green turtles’ diet consists mostly of animal foods such as zooplankton, moss animals, sea serpents, and sea hare eggs.
Kemp’s Ridley Is The Only Species That Routinely Nest During The Day
Most sea turtles nest during the night. However, Kemp’s ridley sea turtles nest mostly during the daytime. While they do nest in the night, this is extremely rare.
It is thought that kemp’s ridley nest during the day to avoid predators such as coyotes. Kemp’s ridley turtles are quite small in size compared to other turtles and as such may be wary of predators such as coyotes. While Kemp’s ridley reaches a weight of 110 lbs, green turtles and other sea turtles can reach weights of 400 lbs and more.
Kemp’s ridley nest synchronously in large groups known as the arribadas. This also helps protect them from predators.
Leatherback Can Thermoregulate
Leatherbacks are the only turtle species known to inhabit subarctic waters. They can survive and thrive in these cold waters because they can regulate their internal body temperature.
The method by which they thermoregulate is known as ‘gigantothermy’. It has been hypothesized that even large dinosaurs may have been gigantothermic.
Although leatherback turtles can thermoregulate their internal body temperature, they are still cold-blooded as they rely on their environment for their body heat.
Leatherbacks thermoregulate by having a low surface-to-volume ratio, and a thick layer of subdermal fat. Additionally, when needed they can lower their body temperature by causing more blood to flow to the surface of their body.
The thick layer of fat in leatherbacks makes them one of the fattier sea turtles if not the fattest.
The Australian Flatback Is The Only Sea Turtle Not Found All Across The World
The Australian flatback sea turtle is endemic to the coastal waters and beaches of the Australian continental shelf.
As you may have guessed, this turtle is only endemic to Australia and it has a flat back (carapace). Its geographic range and the physical description give this chelonian its name.
The flatback has the smallest geographic range of any turtle as it can only be found in the coastal waters of Australia and in particular northern Australia. The species have been occasionally spotted in the coastal waters of Papua New Guinea and the Tropic of Capricorn.
They are known to nest only in Australia with Queensland having the highest concentration of nests.
The Largest Reptile Is The Leatherback
The leatherback is known as the largest reptile or the largest non-crocodilian reptile. This species has been speculated to be capable of reaching a weight of 1982.4 lb or 900 kg.
As you can see this is massive. The average weight range is however 550 to 1,540 lb (or 250 to 700 kg).
The leatherback has a maximum carapace span of 106.3 inches or 270 cm, an average straight carapace length of 57 to 63 inches or 145 to 160 cm & a maximum carapace length of 84 inches or 213 cm, and a curved carapace length of 40 to 68 inches or 100 to 175 cm.
The Temperature Of The Beach Sand Determines The Sex Of The Hatchlings
With leatherback sea turtles a temperature above 29.75 degrees Celsius results mostly in females, and a temperature below 28.75 degrees Celsius results mostly in males. A temperature of 29.5 degrees Celsius results in approximately an equal number of males and females.
With other sea turtles, a temperature above 86.5 degrees Fahrenheit (30.3 degrees Celsius) results mostly in females, and a temperature below 83.3 degrees Fahrenheit (28.5 degrees Celsius) results mostly in males.
All sea turtles exhibit temperature-dependent sex determination. And this temperature is the temperature of the nest and the sand.
Most Sea Turtle Deaths Occur Early In Life
Most sea turtle deaths occur when they are young or even when they are eggs.
In fact, the stats show that about only 1 sea turtle egg makes it to adulthood. Once turtles reach maturity, their rate of death drops significantly.
Sea turtles usually reach maturity at the age of 30 years. This varies from one species to another.
The main reason why adult turtles have a low death rate is because of their huge sizes and protective shell. As such, very few animals can successfully attack and kill them. They have very few predators. And they mostly are large sharks.
Olive Ridley And Kemp’s Ridley Nest In Large Groups Called Arribadas
The arribada means arrival in Spanish. This is a phenomenon where hundreds and even thousands of nesting females synchronously nest on the same beach at the same time.
Places, where the arribada happens, include the Caribbean in countries such as Costa Rica and Panama. The arribada is also known to occur in the United States such as in texas.
They also occur in Central & South America as well. In Nicaragua, you can witness the arribada in Corazon, La Flor, and Chacocente.
The turtles that participate in the arribada include the olive ridley and Kemp’s ridley. The arribada attracts a lot of tourists and is a sight to behold.
Only 1 Out Of 1,000 Hatchlings Survives To Adulthood
The estimation is that only 1 in 1000 hatchlings reach adulthood. This is because as babies, sea turtles are very susceptible to attacks.
Hatchlings and juveniles have a lot of predators. While adults have few predators, juveniles and hatchlings have countless.
Some predators of hatchlings and juveniles include ants armadillos, bears, lynxes and bobcats, crocodiles, dogs, hogs, pigs, crabs, crows sharks such as great whites, tiger sharks, whitetip sharks, requiem sharks, skunks, cats, jackals, seagulls, raptors, rats, groupers, herons, gulls, honey badgers, octopi, ray-finned fishes, crocodiles, foxes, possums, raccoons, and even other sea turtles.
On the other hand, adult sea turtles’ main predators are sharks. Crocodiles and killer whales are known to hunt sea turtles and big cats such as jaguars are known to attack nesting females.
But for the most part, an adult sea turtle doesn’t have to worry about predators.
Sea Turtles Are Among The Few Creatures That Eat Sea Grass
Very few animals eat seagrass and sea turtles are one of these animals. To be specific, it is the green turtle that mostly eats sea grass.
Sea turtle feeding on seagrass is important to the ecosystem since it is one of the few creatures to do so and maintaining the length of the grass helps them to grow across the sea floor.
In summation, the consumption of seagrass by sea turtles ensures that the seagrass bed is healthier. A lot of marine animals including fish use this seagrass bed for breeding and it also plays an important developmental habitat for these animals.
Without sea turtles feeding on seagrass many marine animals that humans harvest and consume will go extinct or become endangered.
Sea Turtles Are Omnivorous
Sea turtles are omnivores. The status however depends on the species and even the age of the individual.
Green turtles change throughout their life. While they are omnivorous as juveniles feed on mostly animal foods such as zooplankton, moss animals, sea serpents, and sea hare eggs, they are exclusively herbivorous as adults feed on seagrass and algae.
Leatherbacks are carnivorous and feed mostly on jellyfish. Olive ridley, kemp’s ridley, loggerhead, and hawksbill sea turtles are omnivorous all their lives.
They are known to feed on fish, worms, echinoderms, cnidarians, mollusks, sponges, seaweed, seagrasses, and decapods. Some species may mostly feed on a particular prey.
Hawksbill feeds mostly on sea sponges. In the Caribbean, about 70 to 90 percent of a hawksbill diet is composed of sea sponges.
Sea Turtles Are Poikilotherm
Sea turtles are poikilotherms. This means that their main source of body heat is the environment and as such the temperature of the environment plays a huge role in their body temperature.
Poikilotherms are also known as cold-blooded or ectotherms. One adaptation found in poikilotherms that helps them to prevent loss of body heat is gigantothermy.
This adaptation has been mentioned earlier in the fact about leatherbacks are able to thermoregulate. Leatherbacks still rely on their environment as the main source of their body heat.
With gigantothermy, there is less body surface in ratio to the body volume. This allows them to reduce heat loss significantly.
This coupled with a thick layer of fat allows the leatherback to thrive in even the coldest of oceans.
Sea Turtles Are The First Biofluorescent Reptiles and Marine Reptile Discovered to Occur Naturally In The Wild
In 2015, David Gruber, a marine biologist, and an explorer discovered a biofluorescent marine tetrapod, to be specific a biofluorescent hawksbill turtle. This is the first time in history that biofluorescence has been observed in marine reptiles.
While fluorescence is widespread in fish, it has never been observed in reptiles until 2015 when it was observed in reptiles and in particular this turtle. Biofluorescence means that the animal can absorb light (higher energy wavelengths, for example, UV) and reemit this energy at a lower wavelength.
Maybe in years to come, biofluorescence will be discovered and observed in other reptiles. However, the first will be the hawksbill, a sea turtle.
Sea Turtles Breathe Air
Although sea turtles are marine animals, they have lungs just like all other reptiles. This means that they breathe air. As such, turtles need to resurface regularly to breathe.
Because sea turtles breathe air, they can drown when trapped underwater. Sea turtles have been known to get trapped in fishing nets and drowned.
Sea turtles can hold their breath for hours. How long the turtle can hold its breath depends on what it is doing. If the turtle is going about with its daily routine, it can hold its breath for 45 to 60 minutes.
When sleeping or hibernating, they can hold their breath for up to 7 hours. When stressed or doing activities that burn a lot of energy, they need to resurface every few minutes.
Sea Turtles Can Stay Underwater For Long Periods Of Time
Sea turtles can remain underwater for up to 7 hours. However, as mentioned earlier this is dependent on the activity level of the turtle.
Hibernating and sleeping turtles can remain underwater for as long as 7 hours and usually remain underwater for several hours. During the day, the turtle will resurface every few minutes to breathe before going back underwater.
They are capable of remaining underwater for 45 to 60 minutes when needed. If stressed, the turtle will need to resurface within minutes or risk drowning.
Sea Turtles Use Their Rear Flippers To Dig Up Their Nests
When they have to construct a nest, the female turtle uses the rear flippers to dig the egg cavity. This egg cavity is tear-shaped.
The turtle starts the nest construction process by crawling to a dey portion of the beach with loose sand. She then uses her flippers to fling away the sand. She does this to construct a body pit.
After constructing the body pit, she then proceeds to use her rear flippers as shovels to scoop out sand and construct an egg cavity or chamber. After she has dug out the egg chamber, she will then lay the eggs in it.
The average clutch size ranges from 70 to 120 eggs. After laying the eggs, the nesting female will then use her rear flippers to cover the egg chamber with sand.
She then tries to disguise the nest by refilling the body pit and throwing sand in all directions. Only when the nest is properly disguised will the female turtle leave.
Unless she is threatened or feels like she is in danger. Nesting females have been known to abort the nesting process when threatened or disturbed.
Fun Sea Turtle Facts for Kids
Here are some cool sea turtle facts for kids. Sea turtles refer to species found in the families Cheloniidae and Dermochelyidae. They are called sea turtles because they live in the sea.
- Sea turtles are reptiles although they live in the sea.
- Some sea turtles can glow in the dark – the Hawksbill turtle has been known to glow in the dark.
- Green sea turtles are not green in color. Rather they are black in color.
- The leatherback turtle is the largest turtle in the world
- The Australian flatback is found only in Australia.
- Some sea turtles eat seagrass.
- Sea turtles are cold-blooded.
- Sea turtles need to breathe air just like humans.
- Although they are huge as an adult, sea turtles are only about two inches in size when they are babies.
- Sea turtles feed on both plants and animals.
- Green turtles eat a lot of seagrasses and are the only adult sea turtles that are herbivores.
- Hawksbill mostly eats sea sponges.
- Leatherbacks mostly eat jellyfish. So do flatbacks and olive ridley turtles.
- Sea turtles typically live in tropical and subtropical waters.
- Sea turtles spend all their time in water and only return to land to nest.
- They can travel thousands of miles just to reproduce.
- Nesting females lay about 70 to 120 eggs per clutch.
- Nesting females usually return to the beach they hatched on to lay eggs.
- Hatchlings leave their nests at night and rush to the sea immediately after hatching.
Sea turtles include species that are found in the families Cheloniidae and Dermochelyidae. Sea turtles are also known as marine turtles.
They are called sea turtles because they spend most of their lives in the sea. The only times you will see sea turtles on land are when they have to nest, when they are hatchlings rushing to the sea, or when they become strangled on a beach by accident.
The seven species of sea turtles are olive ridley (Lepidochelys olivacea), Kemp’s ridley (Lepidochelys kempii), loggerhead (Caretta caretta), leatherback (Dermochelys coriacea), hawksbill (Eretmochelys imbricata), green (Chelonia mydas), and flatback (Natator depressus) sea turtles.