What Do Green Sea Turtles Eat?

Written by Jeremiah Wright
Published: September 30, 2022
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Green sea turtles are a large turtle species that inhabits the worldwide waters! They are among the few (if not the only!) species with omnivorous juveniles and herbivorous adults.

While green sea turtles do not have many predators in the wild, they face many other threats that made the IUCN list them as endangered. Keep on reading to find out everything about their diet and threats!

What Are Green Sea Turtles?

leather-back sea turtle

Green sea turtles represent the only species in the




Green sea turtles belong to the Cheloniidae family and represent the only species in the Chelonia genus. They are scientifically called Chelonia mydas. Other common names are black turtle, green turtle, and Pacific green turtle. They live in tropical and subtropical waters worldwide, with larger populations in the Atlantic and Pacific Oceans

A green sea turtle’s flattened body is covered by a large carapace that is a combination of olive and black colors. The turtle has paddle-like flippers that are well-adapted for swimming.

Adult green turtles can reach 5 feet long and weigh 150 – 419 pounds! Some very large individuals reached almost 700 pounds. The largest green sea turtle weighed 871 pounds, and its carapace measured 60 inches long!

Adult green sea turtles prefer living in shallow lagoons but often migrate long distances, reaching even islands! Did you know that some islands are called Turtle Islands only because many green sea turtles roam around their beaches?

This turtle species is listed as endangered. They are protected from exploitation by law in many corners of the world, where it’s illegal to harm, collect, and kill them. Moreover, their habitats are threatened by pollution and real estate development. 

What Do Green Sea Turtles Eat?

Turtles breathe out of their butts

Adult green turtles eat lots of green and red algae, red moss, sea lettuce, green seaweed, crinkle grass, freshwater red algae, and seagrass.

©iStock.com/Greg Sullavan

Green sea turtles are herbivorous animals. However, there’s much more to that than just a simple fact! Why? Let’s find out!

Juvenile green turtles aren’t herbivorous. They are born carnivorous and slowly transition to a herbivorous diet as they grow older. Baby green turtles eat fish eggs, hydrozoans, bryozoans, jellyfish, mollusks, small invertebrates, worms, algae, and crustaceans. As you can see, their diet is pretty diverse. On the other hand, their diet’s nutritional value isn’t too favorable for their development, that’s why their growth rate is pretty slow. 

As they grow older, green turtles start eating lots of green and red algae, red moss, sea lettuce, green seaweed, crinkle grass, freshwater red algae, and seagrass. This diet has affected their body fat by turning it green – in fact, that’s where their name comes from, not their carapace color. 

Green sea turtles also eat large quantities of Avicennia schaueriana and Sporobolus alterniflorus

But how do they chew this vegetation? Easy! Their skulls have adapted to this diet, and their serrated jaws greatly help them tear the grass apart and chew it. 

Top 10 Foods Green Sea Turtles Eat

Here’s a list of 10 foods juvenile green sea turtles eat:

  • Mollusks
  • Fish eggs
  • Worms
  • Sponges
  • Algae
  • Crustaceans
  • Jellyfish
  • Bryozoans
  • Hydrozoans
  • Sea hare eggs

Here’s a list of 10 foods adult green sea turtles eat:

  • Green algae
  • Red algae
  • Lobster horns
  • Red moss
  • Sea lettuce
  • Crinkle grass
  • Freshwater red algae
  • Seagrass
  • Green seaweed
  • Wetland plants

What Eats Green Sea Turtles?

Green Sea Turtle in the Sand

Juvenile green sea turtles fall prey to crabs, birds, and other small marine mammals.

©Magdalena Paluchowska/Shutterstock.com

Adult green sea turtles do not have too many predators in the wild. Their only known predators are larger sharks, especially tiger sharks.

On the other hand, juvenile green sea turtles are at a much higher risk in the wild. They can fall prey to crabs, birds, and other small marine mammals. Even their eggs are preyed on by golden jackals and red foxes. However, if they get to maturity, they’re pretty safe in the water!

However, many other things threaten their population. First, they are prone to becoming infected by many parasites, such as leeches, protozoans, barnacles, cestodes, and nematodes. Cestodes, nematodes, and protozoans cause many deaths among the green sea turtle population.

Another major disease threat is fibropapilloma disease, a sea turtle disease that causes epithelial tumors on the surface of biological tissues such as the lungs, stomach, scales, and kidneys. This disease is transmitted by leeches and is often lethal.

Human Threats

Humans are a great threat to green sea turtles. Turtles’ skin was historically used for handbags, while their flesh was a culinary delicacy. Green sea turtles’ fat, flesh, and cartilage were the main ingredients for one of the most popular dishes of the 19th century – turtle soup. Historically, in Java, Indonesia, humans even collected sea turtle eggs!

Nowadays, green sea turtles are sold along Java’s south coast as whole, stuffed animals or turtle oil. They are called “minyak bulus.”

The turtle-human relationship hasn’t changed much; that’s why green sea turtles are now endangered. Although some countries prohibit hunting, green turtles are still greatly affected by boat strikes, fishing nets, and habitat destruction.

Chemical pollution can cause severe turtle diseases, including tumors, while light pollution may disturb hatchlings, which are already at risk of being preyed upon. 

Interesting Green Sea Turtle Facts:

  1. Green sea turtles are the largest species in the hard-shelled sea turtle family!
  2. Hawaiian green sea turtles love climbing on beaches and enjoying the sun!
  3. Green sea turtles may live up to 70 years! They reach sexual maturity sometime when they are 25 to 35 years old.
  4. Green sea turtles live in waters that surround more than 80 countries around the world! Their largest nesting populations are in Costa Rica and Australia.
  5. Green sea turtles can spend up to five hours underwater!
  6. Green sea turtles are excellent swimmers. They have recorded swimming distances of more than 1,600 miles!
  7. If they feel threatened, green turtles can reach a speed of 21.7 mph!

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The photo featured at the top of this post is © iStock.com/Greg Sullavan

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About the Author

I hold seven years of professional experience in the content world, focusing on nature, and wildlife. Asides from writing, I enjoy surfing the internet and listening to music.

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  1. American Oceans, Available here: https://www.americanoceans.org/species/green-sea-turtle/
  2. Oceana, Available here: https://oceana.org/marine-life/green-turtle/
  3. NOAA Fisheries, Available here: https://www.fisheries.noaa.gov/species/green-turtle