Scientific Facts
| Common Name: | Green sea turtle |
| Scientific Name: | Chelonia mydas |
| Life Span: | Up to 75 years |
| Size: | 1 to 1.2 meters long |
| Habitat: | lagoons, inshore bays, or shoals |
| Country of Origin: | South America and South Africa |
Physical Description
Green tea turtles are among the biggest turtle species all over the world. They weigh 65 to 130 kilograms and measure 1 to 1.2 meters long. These turtles have a tough, tear-drop shaped shell known as the carapace. It covers a big part of their bodies, except for their heads and flippers. The carapace of the green sea turtles may include shades of olive, green, brown, black, and yellow.
These turtles are easy to distinguish from other species as they have a pair of prefrontal scales located in front of their eyes while other sea turtles have two pairs of these scales. Their heads are small and blunt with their serrated jaws. Their carapaces are bony with no ridges and have large and non-overlapping scutes or scales. They have a total of four lateral scutes.
Their bodies are almost oval and flattened, unlike the bodies of the Pacific green turtles. Their flippers have one visible claw. The color of their carapaces ranges from light to darker green and plain to bright yellow with green and brown tones and radiating stripes.
For their plastrons, the colors may vary from dirty white, white to yellow in those species living in the Atlantic region while it’s dark grey to bluish-green for the populations living in the Pacific. The hatchlings of green sea turtles are either almost black or dark brown with a shade of white underneath and white margins on their flippers.
The Pacific green turtles or black sea turtles have strongly vaulted or elevated bodies that appear less round on the frontal side compared to other green sea turtles. The main difference associated with the Pacific greens is in the color as their carapaces can be black or dark grey. The hatchlings are black or dark-brown with white narrow borderline with white underpart.
Habitat
The green sea turtles move on 3 types of habitats based on their life phase. The females lay the eggs on the beaches. The fully grown turtles are typically in the shallow and coastal waters that have lavish seagrass beds. Some of them stay in lagoons, inshore bays, or shoals that have lavish seagrass meadows.
Their generations usually migrate between a pair of nesting and feeding sites. The green sea turtles are categorized as aquatic species that are widely distributed across the world in hot tropical and sub-tropical waters. The ecological limitation that restricts the distribution of these turtles is the ocean temperature that ranges between below 7-10 degrees Celsius.
In the geographical range, these sea turtles often stay close to the island and continental coastlines. Beside the coastlines, these turtles live in the shallow bays or protected shores. In the protected bays and shores, the green sea turtles live in the coral reefs, nearshore seagrass beds, and salt marshes. In the coral reefs, they eat the brown, red, or green algae.
At the same time, the coral reefs protect them against predators or rough storms in the sea. The seagrass beds and salt marshes contain grass vegetation or seaweed, providing ample habitat for sea turtles.
Turtles spend the first 5 years of their lives in the convergence areas in bare open seas surrounding them. The juveniles are seldom seen because they often swim in the deep and pelagic waters. These turtles can swim at 2.5 to 3 kilometers per hour.
Development
The female turtles will lay eggs that are in 35 to 58 millimeters in diameters. Like most turtles, the green sea turtles develop based on the temperature. The eggs laid in colder temperatures below 28.5 degrees Celsius are more likely to be males. Those eggs laid in warmer temperatures are more likely to become females.
Both sexes incubate in the soft and white shells for 30 to 90 days, depending on the season – wet or dry. The incubation usually occurs in a wet period. When the hatchlings leave their nest, their carapaces are dark blue-black and around 5 centimeters long.
The hatchlings weigh 25 grams. Their plastrons are either white or yellow. Their skin is dark black. While the hatchlings grow into young turtles, their carapaces measure around 40 centimeters long. The sub-adults measure 70-100 centimeters long. While the hatchlings turn into juveniles, they will take 27 to 50 years to be fully mature.
After 2 months, the babies use the “egg tooth” in breaking their shells to come out of the eggs. As they do, the race will begin. They should make a quick trip to the water from the sand as predators like crabs, birds, lizards, and wild dogs might be there to eat them.
The young turtles float on the sea waters and feed on the plankton. They will eventually move to the shallow water along the shore, like lagoons, and lie to find seagrass, which is their food.
Reproduction
The green sea turtles have several partners throughout their life. Copulation takes place within the shallow waters. The males mount on females and hold on their mating notches that are around the shoulders of the females that aid in copulation. The male turtles join the mating partners by latching on the males that will last for hours. The males will try to dislodge the male mounted on the female.
The copulation among the green sea turtles lasts for more than 100 hours. The females take 15 days from the time the male mounted on them to the period they try to nest on their natal beaches.
Mating
The females will revisit the natal beaches in the next 2 to 4 years to breed in June until September. If they don’t come back to the natal beach, these turtles will choose a beach that has the same sand color and texture as the first one.
Though they don’t complete each action, the breeding process generally starts with the turtles going to the beach and select a perfect nesting site. Then, the females will start clearing the site by removing debris. They will also dig a hole using their front legs.
Once they lay the eggs, they will fill their nesting spot with sand to hide the eggs. After that, they will leave and go back to the water. The female green sea turtles lay 1 to 9 clutches in just one nesting period, but they release 3 clutches in most cases.
Each clutch may have 75 to 200 eggs. These eggs will take 45 to 75 days to hatch. The hatchlings will start their lives by going to the water, where they will be safer from the predators living on the land area. From being hatchlings to juveniles, the green sea turtles stay young in the nest 27 to 50 years before they become fully mature.
Longevity or Life Span
Limited information is available about the life span of the green sea turtles because of insufficient tagging. A report said green sea turtles could live for up to 75 years. They aren’t typically held for a long time in captivity, so there is no information regarding their longevity.
Behavior
The green sea turtles migrate in big groups, which often originate from the original natal beach. These species love to swim, so they can travel at a maximum distance of 20 to 90 kilometers per day. They can be found diving, eating, migrating, or reproducing.
Young green sea turtles can swim faster than other species of sea turtles like the loggerheads and olive ridleys. Their secret is the way they stroke their front flippers.
When the breeding period comes in, the actively copulating pairs often catch the attention of other male green sea turtles who will try to separate the male from its partner. They may also latch onto the pair.
If the male feels threatened by other males, the turtle may remove itself from the female shortly to kick off the “escorts”. Although humans are considered predators of the green sea turtles, many of them aren’t involved with human contact as they swim or when they mate.
Perception and Communication
The green sea turtles use their eyes to detect plants and other food items. They also use some visual displays in communicating. Moreover, they use wave circulation direction that aids them in navigating under the water.
They can also use magnetic channels to learn how to swim in deep waters. A study revealed that the inner ears of the green sea turtles could effectively detect the wave direction and acceleration that supports their sense of route.
Female turtles use 2 displays in communicating with males if they want to mate or not. They will show their willingness to mate by being so submissive when the males try to mate on them.
However, females show disapproval to mate if they swim away while keeping their hind legs closed or bite the males if they try to come closer to females. Also, females portray the so-called “refusal position” that entails floating upwards with their plastrons facing the males and their limbs extended.
Diet/Food Habits
Adult green sea turtles consume more seagrasses and algae. Adults are herbivores, which means they eat nothing else apart from plants. The baby green sea turtles consume algae but will feast on worms and crustaceans, so they are omnivores.
The green sea turtles start their lives in eating both meat and plants. They will slowly switch to an herbivore diet as they age. Young green sea turtles eat tiny aquatic invertebrates, including the neustonic material such as the sea serpents, sea hare eggs, and most animals. They consume wetland plants like api api and salt-water cordgrass in big quantities. These plants are more common in the salt marshes.
Their diet comprises of various green and red algae like the red moss, filamentous red algae, freshwater red algae, sea lettuce, lobster horns, green seaweed, and crinkle grass. Since the green sea turtles are extremely mobile since birth, their choices when it comes to food are generally opportunistic.
Predation
The hatchlings of green sea turtles are more susceptible to predation compared to adults. Different land mammals like jaguars, red foxes, feral dogs, and golden jackals, crustaceans, and reptiles feast on the eggs of these turtles. Even humans become predators for these animals. Hatchlings are defenseless, and the only thing they can do to protect themselves is to swarm in big groups going to the water as soon as they come out of the eggs.
However, the danger for them is not yet over even when they are already on the water. Deep down, some animals can become their new predators. These include tiger sharks and whitetip sharks.
Young and adult green sea turtles can still be prey for those bigger animals. Good thing, the fully grown green sea turtles have big and tough hard shells that protect them against the predators. When the female species come out of the water going to the shore, their limbs and heads become vulnerable to predators.
Distribution
The green sea turtles exist in the Atlantic Ocean that range from the east portion of the US along the shore of South America extending to South Africa. These turtles are also common in some portions of the Mediterranean and the Caribbean Sea and even across the Indian Ocean and the Pacific Ocean.
They stay most often near islands and to the coastlines. They live in the bay and along the protected shorelines, particularly in the areas with seagrass beds. The green sea turtles are seldom seen in the open oceans.
Their Roles in the Ecosystem
The young green sea turtles are predators of the sea serpents, sea hare eggs, moss animals, and tiny jellyfish. The adult turtles are mainly herbivorous as they eat algae and seagrass in most cases.
These green turtles play a crucial role in the ecosystem by facilitating nutrient turnover and in the regrowth of seagrass. As they feast on seagrass, these animals defecate, and their feces become fertilizers rich in nitrogen.
The Positive and Negative Economic Significance of Green Sea Turtles for Humans
Though most countries established laws that protect all forms of sea turtles, the green sea turtles remain vulnerable to cruelty. Some people catch them for their meat and eggs in some parts of the world, like in Southeast Asia. Their shells are used as home decors or as a raw material for jewelry.
The green sea turtles can be good pets. They don’t pose any threat to humans. They are non-venomous or even carriers of a particular disease.
Threats
The loss of habitat, climate change, and diseases like fibropapilloma threaten the green sea turtles. The federal and state laws and global treaties protect these aquatic animals. However, illegal hunting of wild turtles and harvesting their eggs still occur in some areas.
Likewise, the accidental entanglement in fishing tools like shrimp trawling mesh and gillnets is a major factor associated with the rising number of turtle injuries and deaths occurring every year.
Marine debris and oceanic pollution disrupt and disturb their migration patterns. Light pollution in the nesting areas, vehicle traffic, and the development of the beaches disturb the hatchlings that often go to the light instead of to the ocean.
The increasing sea temperatures caused by climate change also hurt the population of green sea turtles. Since the incubation temperature for the eggs determines the gender of the developing hatchlings, the populations of green sea turtles suffered from imbalances with 90% or more are females. This led to a further decrease in their population in the area.
1) Hatchlings
Hatchlings face most of the same dangers and predators which the eggs may experience combined with some other dangers. In the sea, they are vulnerable to sharks, big fish, and a lot more. Likewise, as they reach the sea, they go on their own that makes them vulnerable to predators as well.
The hatchlings may also encounter human-caused dangers, such as light pollution. They rely on the light source that gives them the brightest lighting so that they can go to the sea. If that source of bright light is not the sea but a house or streetlight, the hatchlings will end up taking the wrong direction.
When the hatchlings go away from the ocean, they become more vulnerable to terrestrial predators. Also, they have just a minimal amount of energy left in their bodies, which they got from the eggs. Therefore, they are weak and hungry. Due to their size, their hatchlings can fall into the gutters or holes and get trapped.
As they face extreme challenges, the chances for the hatchlings to survive is so limited. Just one of them has the biggest chance to endure and survive.
People can do something for these hatchlings, and that is to participate in the headstart programs. These are done for most turtles like the red-bellied cooters where the NMLC joined.
This particular program includes taking the hatchlings from the woods and raising them inside the facility, which will keep them safe and sound from the predators and allow them to grow up and reach maturity. When they reach the ideal size, the turtles will go back to the sea to flourish and reproduce.
2)Young and Adults
Juveniles and adults encounter the same dangers. Humans caused problems that frequently stem from pollution, entanglement, bycatch, active harvest, and destruction of the habitat involving the nesting beaches.
Pollution is a big issue for turtles, particularly littering. Turtles usually mistake the floating plastic bags for food, which can be life-threatening. It may obstruct their digestive tract. If the fishermen don’t responsibly dispose of the fishing line, the turtles may get entangled unexpectedly.
The fishing line looks harmless, but it can cut through the skin of any marine animals and result in deep wounds, infections, and painful amputation. Green sea turtles are victims of the boat strikes.
Housing
The inner surface of a holding tank should be non-abrasive, free of projections and burrs, which can trigger harm to green sea turtles. Also, it must be free from harmful heavy metals or organics like copper and lead paints.
A holding tank that has painted surfaces should be free from the biologically risky materials and should not be flaking or chipping. The tank should be free from a small item that the turtles may bite and swallow. Don’t use a non-finished concrete tank.
Likewise, the holding tank should contain non-food items which might be ingested by the turtles or anything that will obstruct their ability to come up to float or breathe. The holding tank should also have entangling materials. Habitats like rock ledges mimic the items inside the enclosure, allowing the turtles to rest.
On the other hand, these items should be constructed and positioned in a way that the turtles will not be wedged and trapped underwater. The green sea turtles should demonstrate the capability to move safely all over the tank items. The enrichment items, particularly for the non-releasable or resident green sea turtles, should be used just for enhancing the quality of life or prevention of pacing or conditioning behavior.
The tank must ensure the turtles stay inside except when the facility personnel removes them. It should have barriers or railings to prevent the public from getting into the enclosure. If it’s determined that public presence triggers unnecessary stress, the turtles should be inaccessible to the public.
The intakes or drains of the holding tank should be properly constructed and shielded to avoid accidental entrapment. Drains and inflows should be added to ensure proper water flow rates and turnover all over the enclosure.
To help in preventing the water temperature from getting too warm, any outdoor holding cage should be 30% shaded. Shading should be raised to 50%.
Lighting
The tanks where the green sea turtles are kept into should have ample lighting (artificial lighting and sunlight) to allow for quick viewing of the animals in the entire parts of the tank. When artificial lighting is used as the main source of light, regular veterinary assessment should address the dietary or lighting supplement needs depending on the clinical evaluation and available husbandry or medical details.
High-quality full spectrum lights should be used to enhance general health and prevent any possible metabolic issues. If you use a diffuser, care should be taken to guarantee proper full-spectrum exposure.
The photoperiod of the captive green sea turtles should be the same as the natural photoperiod and imitate the winter and summertime daylight hours. Enclosures should not be synthetically illuminated, which will prevent the photoperiod of over 14 hours in every 24 hours.
Shaded or dark areas should be given to let the turtles switch positions. Artificial lighting shouldn’t be excessive to trigger sensitivity. The lights on top of the enclosure should be equipped with shield guards for accidental breakage prevention.
Water Quality
Excellent water quality is crucial to the green sea turtles’ health, especially for those raised in captivity. Facilities should have written processes for checking and maintaining the ideal water quality in every enclosure.
The salinity should be maintained between 20 to 35 ppt. When necessary, green sea turtles might be maintained in less or more saline water for 24 hours every week. Injured or sick green sea turtles might be kept at salinities under 20 ppt or more than 35 ppt as recommended by a registered veterinarian.
The water’s pH level should stay between 7.2 to 8.5. The water temperature must be between 20 to 30 degrees Celsius or 68 to 86 degrees Fahrenheit. Low and high extremes might induce disease, injury, or death and should be prevented. On the other hand, rehabilitating the cold-stunned turtles might require putting the turtles in the water below 20 degrees Celsius or 68 degrees Fahrenheit, allowing them to warm slowly.
Common Health Problems in Green Sea Turtles
Like other turtles, the green sea turtles are prone to several health problems. One of them is fibropapillomatosis. It is the debilitating skin problem that affects the sea turtles across the world. It causes the green sea turtles to develop malignant lumps on their skin. This condition is more common in the green turtles, but loggerheads, olive ridleys, Kemp’s ridleys, and leatherbacks are also prone to it.
Fibropapillomatosis can be deadly when it invades the internal system of the green sea turtles but will usually heal when tumors are shallow. The scientists also assume that it can be a virus since herpes has been found in 95 percent of all reported cases in Florida.
1) Internal Parasites
There are some internal parasites present in the sea turtles. A few of the most common parasites found pestering the green sea turtles are the blood flukes and flatworms. 33 percent of the loggerheads living on the eastern coast have disease-causing blood flukes. The flatworms are more common in the green sea turtles. Flatworms of all species are found within the gastrointestinal tract, unless for the one that has been living in their bladders. Although the flatworms are parasites, they don’t seem to trigger weakness to these turtles.
Most of the wild turtles would have some type of parasite in or on it. However, the parasite might not be harmful to the turtles until their population increases and exceeds the limit. roundworms are found also in the intestinal or digestive tract of the green sea turtles. However, the turtles generally don’t show any sign of a bad effect due to these parasites.
2) External Parasites
These include the leeches and other species that reside in the shell known as epibiota. Leeches are normally seen across where their flippers connect to the other parts of their bodies. Mollusks, barnacles, polychaetes, algae, and amphipods are all epibiota. These organisms, including the leeches, are more common on the loggerheads, but other species, including the green sea turtles, can have them.
Usually, epibiota seems to not affect the sea turtles because these organisms and the animals are in the “commensal” relationship. Thus, the epibiota will benefit from this relationship. The turtles will not receive detriment or benefit from these organisms. Healthy turtles may control the number of organisms by scraping them off using their flippers. Likewise, as the young green sea turtles grow, they will shed their scutes, so a few organisms will be eliminated. However, when the turtles are sick, they might not be strong to limit the population of these organisms. The external and internal parasites would compound. When too many organisms look for a home on the turtles’ shells, this will reduce their speed and drag them down. When the turtles do not scrape these organisms off their bodies, they may eventually turn into permanent residents. Some of the barnacles are just found on the shells of sea turtles.
The green sea turtles are healthy if they are alert and active. They eat regularly. Their shells are hard and healthy without lesions. Clear and bright eyes without swelling. Their skin looks healthy without sores. Their vents and noses are clear. All these things show up in healthy green sea turtles.
However, they may be sick if there is a discharge in their nose, eyes, and mouth. Also, check their health if they have spots, bumps, and discoloration on their shells and skin. The sick green sea turtles can be lethargic and look frantic when they swim. You may also see them sneezing and with a runny nose. Their beaks can be overgrown. There might be inflammation at the back of their tympanum.
Availability – Where to Get One?
The green sea turtles may not be unavailable for purchase. If you want to be a caretaker of the hatchlings, then you should do your homework. Visit the concerned government office in your area to know how you can take care of the green sea turtles.
How to Care for Green Sea Turtles?
The green sea turtles can be good pets if they are widely available. In taking care of these turtles, one needs to provide it with the basics:
- A clean and spacious tank
- Water bowl filled with fresh and clean water
- Nutritious food items
Likewise, you need to check often the temperature and humidity inside the cage. You have to watch out for the possible diseases that green sea turtles may incur.
Fun Facts About the Green Sea Turtles
- They are called green sea turtles for a reason. They got their names from the inner sheet of green fat in them.
- Most islands all over the world are called the turtle islands. That is because these areas are hosting the nesting female green sea turtles.
- Like other sea turtles, the green sea turtles can also live for a long time. Their estimated life span is up to 80 years old.
- The green sea turtles are breathing oxygen, but they may stay underwater for 2 hours before they come up to the water surface and take a deep breath.
- The green sea turtles get rid of the excessive salt by using their salt glands located close to their eyes. It makes them look crying.
FAQs
Where do the green sea turtles live?
The green sea turtles exist all over the world with warm tropical and subtropical ocean waters. Some species that have different colorings or markings live in the Pacific Ocean, Indian Ocean, and the Atlantic Ocean.
Are the green sea turtles aggressive?
The green sea turtles aren’t aggressive except when they are in danger. However, if you try to come closer to these animals, you run the risk of getting yourself bitten.
Do the green sea turtles bite?
These turtles have strong jaws and sharp beaks. They are less likely to bite, but their bite can be painful.
What are the predators of green sea turtles?
Crabs, fire ants, dogs, wild pigs, raccoons, dolphins, coyotes, sharks, and some carnivorous fish like grouper, barracuda, and snapper are the most common predators of green sea turtles. The fire ants feast on the eggs and hatchlings.
What is the usual behavior of green sea turtles?
The green sea turtles are not sociable in general, but they often go in groups during the mating season. They spend most of their time in the water, but sometimes they gather on the shore.
Do green sea turtles love being handled?
The green sea turtles don’t like to be touched. Also, they have been endangered animals, so touching or even getting closer to the wild species is strictly prohibited.
Why are the green sea turtles essential?
The green sea turtles have been playing a crucial role in ocean ecosystems. When they graze on the seagrass, they increase the nutritional content and productivity of the seagrass blades.
Do green sea turtles ingest venomous species like the jellyfish?
It may sound uncommon, but the green sea turtles can eat jellyfish. Their diet is more on plants, but they can also eat other animals like jellyfish.
