Turtles can be divided into three subgroups, namely freshwater turtles (commonly referred to as turtles), land tortoises (commonly referred to as tortoises), and sea turtles. As evident by their name, sea turtles can be found in the sea.
There are seven species of sea turtles and they all feed on many different foods. These include jellyfish, salps, fish, algae, fish, cnidarians, crustaceans, sponges, and even mollusks.
These chelonians spend most of their lives in water, and usually only venture out to lay eggs. So what do sea turtles eat? Well, this will depend on the species as well as the habitat of the species.
Sea turtle species are primarily carnivorous although they feed on both vegetation and animal matter. While most sea turtles eat a wide variety of foods, some such as the leatherback turtles and hawksbill turtles have diets consisting mainly of just one food type.
For example, leatherback sea turtles feed primarily on soft-bodied invertebrates such as jellyfish. Hawksbill turtles, on the other hand, feed primarily on sponges that are found on coral reefs.
Flatbacks are carnivorous and feed mostly on a wide range of prey such as arthropods, mollusks, and marine invertebrates. Loggerheads are also primarily carnivorous and feed on marine invertebrates mostly. The same can be said for the olive ridley and Kemp’s ridley sea turtles.
Of course, sea turtles housed in artificial enclosures have to be fed by humans and as such, their diets are usually different from that of wild sea turtles. Since sea turtles are not kept as pets, this article tackles their dietary needs in the wild.
Table of contents
What Do Green Sea Turtles Eat?
The green turtle is also known by several names including the black turtle, the green sea turtle, and the black sea turtle.
The binomial name of this marine species is Chelonia mydas. There are also several subpopulations such as the Hawaiian green turtle, the pacific green turtle (which includes the Hawaiian green turtle), and the Atlantic green turtle.
This sea turtle’s diet changes with age. While hatchlings and juveniles are more carnivorous, adults are primarily herbivorous. Growing green sea turtles need more protein than adults do. So what do green sea turtles eat?
The prey that the young eats include crustaceans, sponges, worms, small marine invertebrates, mollusks, neustonic organisms like sea serpents (Hydrozoa), jellyfish, sea insects, moss animals (Bryozoa), and fish eggs (such as sea hare eggs (Aplysia)). Juveniles also eat plant matter just like adults eat.
Adults, on the other hand, do not eat animal foods. Some plants that green sea turtles consume include a wide variety of red and green algae, salt-water cordgrass (Spartina alterniflora) found in salt marshes, and api-api (Avicennia schaueriana), crinkle grass (Rhizoclonium), green seaweed (Gayralia), sea lettuce (Ulva lactuca), and lobster horns (Polysiphonia).
The algae that the turtle eats include freshwater red algae (Compsopogon), red moss (Caloglossa), and filamentous red algae (Bostrychia).
In fact, this chelonian is known as the green turtle not because of the coloration of its skin or shell but rather because of the color of the subdermal fat found between the shell and the inner organs. The greenish coloration of the fat is because of the vegetation they consume.
As opportunistic feeders, these turtles eat what is available. There is a correlation between the dietary shift and the turtle’s physiological changes.
As the turtle grows, the morphology of the skull changes. The serrated jaw of adults helps them effectively consume vegetation.
Important Feeding/Foraging Habitats of The Green Turtle
The feeding habitats of this species are usually coastal. Some important feeding habitats include Florida (specifically Cedar Key in Levy County, Crystal River & Homosassa in Citrus County, Florida Bay, Florida Keys, and Indian River Lagoon), secluded coastal areas of French Guiana and Suriname, Philippines, and the Sonoran Coast of the Gulf of California.
What Do Loggerhead Sea Turtles Eat?
Loggerhead sea turtles, commonly known simply as loggerheads, are omnivorous.
The loggerhead is so-called because of the large head and powerful jaws of the species. The binomial name of this marine species is Caretta caretta.
This turtle is the largest hardshell sea turtle reaching a weight of more than 1000 lb or 450 kg although on average the species weighs about 300 lbs or 135 kg.
Their diet consists mostly of bottom-dwelling invertebrates such as shrimps, decapods, bivalves, and gastropods. While these foods are the species’ primary food source, the loggerhead has the largest prey list of any oceanic turtle.
Other prey that the loggerhead commonly eats include sea cucumber, aquatic insects, fish (including hatchlings, adults, and eggs), starfish, sand dollars, sea urchins, bryozoans, Portuguese man o’ war (Physalia physalis), isopods, brachiopods, barnacles, cephalopods, sea anemones, bristle worms, and sea pens.
During migration, these interesting species feed on flying fish, squid, floating egg clusters, floating mollusks, and jellyfish. They also feed on juvenile turtles including juvenile loggerheads.
Plants the loggerhead feed on include vascular plants also known as tracheophytes, algae, seaweeds, and corals. The loggerhead sea turtles have large and powerful jaws which they use to crush their food before swallowing.
Important Feeding/Foraging Habitats of The Loggerhead
The loggerhead can be found all across the world’s oceans and can be found in all the oceans apart from the Arctic and the Southern Oceans. The feeding habitats of the species are mostly close to the shore.
For instance, the coast of Baja California serves as a feeding habitat for the eastern pacific subpopulation. The western pacific subpopulation’s feeding habitats include the southwestern Pacific and the East China Sea.
The Indian Ocean populates are known to forage in the Arabian Sea, along the coastlines of the Arabian Peninsula and Africa.
In the Mediterranean Sea, the loggerhead is known to feed in the Adriatic Sea (particularly in the northeastern part above the Po Delta) and the Alboran Sea.
In the Atlantic Ocean, important foraging habitats include the Gulf of Mexico and along the southeast coast of North America.
What Do Kemp’s Ridley Sea Turtles Eat?
Kemp’s ridley sea turtle is the rarest sea turtle in the world. This rare species is unsurprisingly critically endangered. The binomial name of this marine species is Lepidochelys kempii.
The Kemp’s ridley is one of the smallest sea turtles with a weight of 66 to 110 lb or 30 to 50 kg. The carapace is grayish olive and the plastron is yellowish.
Lepidochelys kempii is omnivorous but feeds primarily on floating crabs. Other prey of this sea turtle includes jellyfish, shrimps, mollusks, fish, crustaceans, and sea urchins. Plant matter the Kemp’s ridley sea turtle eats includes algae, seaweed, and vegetation.
Kemp’s ridley sea turtle is also known as the Atlantic ridley. This turtle is known as the Atlantic ridley as its geographic range is limited to the Atlantic Ocean from the Canadian provinces of Newfoundland and Nova Scotia to Bermuda.
There are rare occasions when the species have been found in Europe and the Mediterranean Sea. However, most of the species are found along the Atlantic coast of North America and in the Gulf of Mexico.
Important Feeding/Foraging Habitats of The Kemp’s Ridley
The feeding habitats of the species are mainly in the Gulf of Mexico. Almost all the adults of the species can be found in the Gulf of Mexico. Here they feed in shallow waters with a depth of usually 50 meters or less. These shallow waters of the continental shelf (of North America).
The females can usually be found from the Yucatán Peninsula to the Florida Peninsula. The males can be found in the western gulf portions of Veracruz and Tamaulipas in Mexico and Texas in the United States.
What Do Leatherback Sea Turtles Eat?
The leatherback goes by several names and these include the leathery turtle, the luth, and the lute turtle. The binomial name of this marine species is Dermochelys coriacea.
The Leatherback sea turtle is the heaviest turtle species and the fourth-largest modern reptile. This massive turtle has a weight range of 551 to 1982 lb or 250 to 900 kg.
The leatherback is called such because of the lack of a bony shell. Instead, skin and oily flesh cover their carapace. So what do leatherback turtles eat?
The leatherback sea turtle feeds primarily on jellyfish. Occasionally, leatherback turtles eat other soft-bodied invertebrates such as cephalopods and tunicates.
Because D. coriacea feeds primarily on jellyfish, they help control the worldwide jellyfish populations. The jellyfish population boom has several harmful ecological effects.
The leatherback sea turtle is endangered mainly due to ocean plastic pollution. D. coriacea confuses floating plastic materials for jellyfish. Ingestion of plastic can lead to serious health complications as they cannot digest plastic.
Pacific leatherbacks are particularly affected by plastic pollution as they migrate from Indonesia to California. Californians use over 19 billion plastic bags annually with a large percentage of these plastics ending up in the ocean.
Ingesting even the smallest of plastic marine debris can obstruct the digestive tract and cause impaction. This leads to a lack of appetite, constipation, and the inability to eat.
Even when plastic doesn’t cause impaction, it causes nutrient dilution whereby the turtle is unable to absorb the required amount of nutrients needed to mature. Slow maturation means the turtle is slow to reach sexual maturity. This impacts reproduction rates.
Important Feeding/Foraging Habitats of The Leatherback
The leatherback can be found feeding in even cold waters because it is able to maintain a body temperature much higher than its surroundings because of its large body and thick insulating fat layer.
In the Atlantic, the species can be found feeding in the colder waters as far north as the North Sea and as far south as the Cape of Good Hope. The species can be found in the Gulf of Saint Lawrence. The species can be found feeding in these cold waters because of the abundance of jellyfish found here.
In the Pacific, the species forage along the coasts of Washington, Oregon, and California. Here two significant feeding habitats include off the northwest coast of the continental United States close to the Columbia River and off the shores of California.
A lot of plastic can be found in Californian feeding habitats of the species as these plastics enter the habitats from urban centers along the west coast.
The eastern pacific subpopulation feed in the waters of the west coast of South America.
There is very little information on the feeding habitats in the Indian Ocean.
What Do Olive Ridley Sea Turtles Eat?
The binomial name of this marine species is Lepidochelys olivacea.
The olive ridley sea turtle is primarily a carnivorous turtle that feeds on invertebrates such as crabs, tunicates, shrimp, sea urchins, snails, bryozoans, bivalves, lobsters, worms, and jellyfish. They feed in shallow marine waters and estuarine habitats. They mostly feed in shallow soft bottomed waters.
Devoid of all other food sources, the olive ridley will feed on filamentous algae such as the filamentous red algae (Bostrychia).
In captivity, the species have been observed to be cannibalistic. However, this has been observed to happen only in captivity.
Plastic pollution also harms this species as they usually attempt to eat plastic bags and Styrofoam. This causes a blockage of the digestive tract as well as nutrient dilution.
Important Feeding/Foraging Habitats of The Olive Ridley
The olive ridley is also known as the pacific ridley as it is endemic to the pacific ocean as opposed to the kemp’s ridley which is only endemic to the Atlantic. The olive ridley is also endemic to the Indian Ocean and the southern Atlantic Ocean.
The olive ridley is large and can reach a weight of about 100 lb or 45 km. The skin of the species is olive-gray in coloration. The shell of the species is also relatively thin compared to other sea turtles.
The foraging habitats of the species can be found in the warm waters of the tropics of the Indian and Pacific Oceans from southern Africa to Micronesia, Australia, New Zealand, Japan, Arabia, and India.
Important foraging habitats of Southern California are severely contaminated. Contaminants include industrial discharges, solvents, pesticides, sewage, and agricultural runoff. Also, coastal developments such as the building of docks and marinas around and near southern California and Baja California negatively impact the foraging habitats here.
What Do Hawksbill Sea Turtles Eat?
Hawksbill gets its name from the shape of its head which resembles that of a bird’s beak. This appearance makes them easy to identify.
This turtle is quite small compared to other sea turtles such as the loggerhead, the green turtle, and the leatherback. It is larger than the flatback, and the ridleys.
The binomial name of this marine species is Eretmochelys imbricata.
The hawksbill reaches an average weight of 176 lb or 80 kg although its minimum adult weight is 77 lb or 36 kg and its maximum adult weight is 280 lb or 127 kg.
The critically endangered hawksbill sea turtle is an omnivorous species that feeds primarily on animals with its main food source being sea sponges, which can make up to 95 percent of their diets. Due to their dietary needs, the hawksbill sea turtle is referred to as spongivorous species.
Although E. imbricata is a spongivore, it only eats specific sponge species. Hawksbill turtles found in the Caribbean primarily feed on sponges from the class Demospongiae, and the orders Hadromerida, Spirophorida, and Astrophorida.
One highly toxic jellyfish species the hawksbills feed on include the hydrozoan, Portuguese man o’ war (Physalia physalis). They close their eyes when they feed on the dangerous man o’ war so as not to get stung in the eyes (the only vulnerable part of their face). The rest of their head is heavily armored and adequately protected.
They also feed on highly toxic sponges such as the Suberites domuncula, Spheciospongia vesparium, Tethya actinia, Chondrilla nucula, and Aaptos aaptos. Hawksbills are resistant to the toxicity of these sponges.
Other food sources include sea anemones, jellyfish, comb jellies, cnidarians, and algae.
Important Feeding/Foraging Habitats of The Hawksbill
The hawksbill is endemic to the Pacific and Atlantic Oceans and they feed here. In the eastern pacific ocean, the hawksbill usually feeds in the mangrove estuaries including the Gulf of Guayaquil in Ecuador, Estero Padre Ramos in Nicaragua, Gulf of Fonseca in Nicaragua, El Salvador, and Honduras, and the Bahia de Jiquilisco in El Salvador.
The inner islands and islets of Seychelles including Aldabra are important foraging habitats for young hawksbills.
In the Atlantic, the species are known to feed in the waters around Mona Island of Puerto Rico and the waters off Cuba.
What Do Australian Flatback Sea Turtles Eat?
The flatback is also known as the Australian flatback as it is endemic to only Australia. The binomial name of the species is Natator depressus and is the only species within its genus – Natator.
The species have been found as far north as the coast of Papua New Guinea although there is no evidence of the species nesting in Papua New Guinea. They can also be found along the Tropic of Capricorn.
Natator depressus, a turtle native to Australia, is the only sea turtle mostly confined to a single geographic range – the northern waters of Australia (the shallow coastal waters of Australia’s continental shelf). Of all the seven sea turtle species, the flatback turtle has the smallest geographic range.
The flatback sea turtle is carnivorous and hardly ever feeds on vegetation. Food items that make up their diet include soft corals, bryozoans, shrimps, prawns, jellyfish, mollusks, sea cucumbers, and other sea invertebrates that live in shallow waters.
This turtle is known as the flatback because of the flat carapace the species has. This carapace is also a lot thinner than that of other sea turtles.
For this reason, it is believed that the species do not venture to the rocky parts of the coral reefs to feed.
Important Feeding/Foraging Habitats of The Flatback
The feeding sites of these turtles are the shallow coastal waters of northern Australia. Especially at the coral reefs.
The feeding sites of these turtles are under threat. Coastal development has led to the degradation and destruction of the feeding habitats at the coral reefs and coastal areas.
Additionally, coastal developments have led to barriers between the feeding and nesting habitats of these turtles.
Why Do Sea Turtles Eat Plastics? (Sea Turtles and Plastic Pollution)
One of the main reasons why sea turtles eat plastics is that plastic items such as plastic bags resemble jellyfish – one of a staple of several sea turtles’ diets including the diets of the ridleys and the leatherback. Another reason is that discarded pieces of fishing nets resemble marine vegetation such as green seaweed (Gayralia) which is another staple of sea turtles’ diets including the diets of green turtles.
So how much plastic do sea turtles actually eat? Many of us may be thinking – sure, while a sea turtle may have eaten plastics the numbers can’t be that high.
However, the statistics are quite frightening. In fact, it is estimated that over 50% of sea turtles have eaten plastic. So statistically, most sea turtles have eaten plastic. As you can see this number is alarming.
Okay, so what’s the big deal if a turtle eats some plastic? Well, research shows that the likelihood of a sea turtle dying from ingesting single plastic debris is 22%.
The research also shows that the likelihood of a sea turtle dying from ingesting plastic increases to about 50% if the number of plastic debris swallowed increases to fourteen.
When a turtle eats plastic, this can cause injuries to the intestinal tract. Injuries such as cuts. Plastic can also cause blockages in not only the intestinal tract but also in the rest of the digestive system. This blockage can lead to serious injuries and even death.
So what happens if the plastic causes no blockage or injury? Even when the plastic causes no injuries, it causes the turtle to feel full.
The plastic fills up space in the stomach, space that should otherwise be filled with food. As we know, plastic isn’t food and the turtle gets no nourishment from eating plastic. This can lead to the turtle being malnourished which can lead to death.
There are things we can do to minimize the number of plastic debris in the oceans. The less plastic debris there is in the ocean, the less likely it is for a turtle to eat them.
Here are a few things even individuals like ourselves can do.
The first is to not use plastic bags. A lot of grocery stores offer plastic bags as a means to carry your items.
These plastic bags are often used just once before they are thrown away. Instead of a plastic bag, why not use a reusable bag for your groceries? Also, you can refuse the rubber bags that takeaway is sometimes placed in.
Takeaway food often comes with disposable plastics including plastic forks, spoons, and knives. We usually use these cutleries once before we throw them away. To help cut down on disposable plastics, we can decide not to accept these.
Apart from the cutlery and the plastic bag that takeaway food comes in, there are also plastic straws, plastic soda cups, and plastic coffee cups. Even with paper soda and coffee cups, the lids are usually plastic. Having your own reusable cup and cutting down on the use of disposable plastics.
Also, we should not litter our beaches. Apart from not littering, we can also collect plastics we see on the beach.
See our article about the types of pollution impacting sea turtles to learn more.
Frequently Asked Questions
1. Do sea turtles eat jellyfish?
All species of marine turtles eat jellyfish. In fact, jellyfish are one of the staples of several sea turtles’ diets.
The leatherback primarily feeds on jellyfish. In fact, these turtles can endure the cold water where jellyfish thrive. These turtles are able to venture into these cold waters because they are perfectly adapted to swimming and living in low temperatures.
Green turtles also feed on jellyfish. So do loggerheads, Kemp’s ridleys, olive ridleys, hawksbills, and flatbacks.
Sadly, sea turtles may confuse rubber bags for jellyfish and ingest this harmful debris.
2. Are sea turtles omnivores?
While some sea turtles are primarily carnivorous or primarily herbivorous, all sea turtles eat both plant matter and animals.
Green turtles are primarily omnivorous as juveniles and hatchlings but are primarily herbivorous as adults.
Loggerheads, kemp’s ridley, olive ridley, leatherbacks, hawksbills, and flatbacks are primarily carnivorous.
3. How much do sea turtles eat?
The amount of food a turtle eats is dependent on the size/age and the species. Adult hawksbills are known to eat as much as 1200 lbs or 544 kg yearly, according to SeaWorld.
According to National Geographic, leatherbacks are known to eat as much as 73% of their body weight each day. This is about 16,000 calories and several times more calories than they need.
4. Can sea turtles feed on land?
Sea turtles cannot feed out of water. These marine reptiles need water in other to eat and swallow their food as they cannot produce saliva.
They are however able to eat without shallowing too much seawater. This is explained in more detail in the question below which addresses how sea turtles can eat underwater.
5. How do sea turtles eat underwater?
Sea turtles eat underwater by sucking their food and water into their mouth. This suction ensures that their prey is unable to escape once inside the mouth.
Once the food is inside the moth, the turtle then expels the water it took in while sucking in the prey. To ensure that the prey doesn’t escape the turtle raises its tongue to the roof of the mouth so that the prey is trapped but the water can escape.
Sea turtles also have fleshy spines own as papillae that face inwards to the stomach, this makes it difficult for the food to come back up once inside the esophagus.
Not all the water is expelled as the turtle cannot produce saliva and needs the water to help swallow its food. However, once the food is inside the esophageal, the papillae stop the turtle from swallowing too much seawater. The saltwater is then expelled.
As with other reptiles ingesting too much salty water is bad for the turtles’ health. For this reason, sea turtles get rid of the saltwater they intake while feeding.
Similar to other turtles, sea turtles drink freshwater or water is less salt and minerals. The turtle can and does drink large quantities of potable water in a single go.
They also obtain potable water from their marine prey.
6. Do sea turtles eat coral?
Yes, several marine turtles eat coral.
However, they do not eat hard coral as produce hard calcium carbonate skeletons. Instead, marine turtles eat soft coral. These ones do not form reefs and do not produce hard calcium carbonate skeletons.
Two species known to eat coral include loggerheads and Australian flatbacks.
7. Do sea turtles eat algae?
Yes, marine turtles eat algae. Algae is a common staple of many marine turtles especially adult marine turtles.
The loggerhead, green turtle, kemp’s ridley, olive ridley, and hawksbills all eat algae. Some algae that marine turtles eat include filamentous red algae (Bostrychia), freshwater red algae (Compsopogon), and red moss (Caloglossa).
8. Do sea turtles eat shrimp?
Sea turtles do eat shrimp and several other bottom-dwelling invertebrates. Juveniles and hatchlings mostly feed on these bottom-dwelling invertebrates.
Loggerheads, kemp’s ridley, olive ridley, and Australian flatbacks have been documented to feed on shrimps and prawns.
9. Do sea turtles eat crabs?
Sea turtles such as kemp’s ridley, olive ridley, Australian flatback, and loggerhead are known to eat crabs.
10. Do sea turtles eat meat?
Most sea turtles eat meat. While sea turtles do not eat what we mostly refer to as meat, they do eat other types of meat.
When we think of meat we normally think of the flesh of animals such as cattle, sheep, chicken, deer, and other land animals. However, meat refers to any animal flesh that is consumed as food.
Turtles feed on jellyfish, coral, fish, shrimps, sea cucumbers, prawns, bryozoans, sea serpents (Hydrozoa), and several other marine animals.
11. Do sea turtles eat seaweed?
Several turtle species eat seaweed. In fact, the consumption of seaweed gives the green turtle the greenish coloration of its subdermal fat.
Species that consume seaweed include green turtle, loggerhead, olive ridley, and kemp’s ridley.
12. Do sea turtles eat kelp?
Kelps are large algae seaweeds. The green turtle is known to eat large amounts of kelp.
13. Do sea turtles eat fish?
Sea turtles eat fish. The loggerhead is known to eat flying fish (Exocoetidae), and eggs, hatchlings, and adult fish. The kemp’s ridley and green turtle are also known to eat fish.
14. Do sea turtles eat plankton?
Sea turtles are known to eat plankton. Gelatinous plankton is one of the main prey of the leatherback.
15. Do sea turtles eat sponges?
Sea turtles eat sea sponges. The hawksbill, green turtle, and loggerhead are three species that consume sea sponges. The hawksbill is referred to as a spongivore as it primarily feeds on sea sponges.
They even feed on highly toxic sponges such as the Suberites domuncula, Spheciospongia vesparium, Tethya actinia, Chondrilla nucula, and Aaptos aaptos.
16. Do sea turtles eat turtles?
While sea turtles have been observed to bite and even attempt to eat other sea turtles, this behavior is extremely rare and is generally seen in turtle sanctuaries where many sea turtles are kept in close proximity.
Sea turtles are solitary creatures except during mating season. So no, sea turtles do not eat other sea turtles in the wild.
Sea turtles are interesting creatures although many of them are endangered. Generally, they tend to eat small marine animals such as crustaceans, sea sponges, squids, shrimps, sea anemones, and jellyfish (the commonest of sea turtle prey).
Apart from the adult green sea turtle, which is mostly herbivorous, most sea turtles are generally omnivores. What sea turtles eat can sometimes be determined by the physiology of the mouth and jaws. Different mouth and jaw shapes help the turtle efficiently consume different food types.
Leatherback turtles have sharply pointed cusps on their jaws which is particularly helpful when they have to catch and hold onto jellyfish and other soft-bodied invertebrates. Also, with the help of the papillae (a series of sharp downward curving spines found in the mouth and throats of leatherbacks), leatherbacks can easily swallow their prey.
Loggerhead sea turtles have massive and powerful jaws which they use to crush shelled animals such as sea snails and conchs. The serrated saw-like beak of the green sea turtle helps it to efficiently tear seagrass and scrape algae off surfaces.