13 Sept 2023


Green sea turtles are amazing creatures! 

They’re as old as dinosaurs and can be as heavy as motorbikes. They’re one of the biggest hard-shelled sea turtles in the world; they love swimming through tropical or warm subtropical ocean waters, feasting on seaweed and holding their breath for hours at a time, and even more amazing than that, they can be found right here, in the warm coastal waters of Australia. 

Want to know more about this fascinating creature? Let’s dive in! 

Here are nine incredible facts about the green sea turtle.

1. Green sea turtles practice green eating

They say you are what you eat, and green sea turtles take that seriously. 

Unlike other sea turtles, the green sea turtle is herbivorous and eats mostly seagrass and algae. In fact, their diet is so rich in greens that it makes their fat green. It’s the green colour of their fat, not their shells, which are often brown or olive in colour, that gives them their name. 

A green sea turtle among seagrass at Hol Chan Marine Reserve in Belize, Central America.
A green sea turtle among seagrass at Hol Chan Marine Reserve in Belize, Central America. © Antonio Busiello/WWF-US

2. They’ve seen the world, but mostly from underwater

Green sea turtles love to travel and can be found all around the equator. They nest in over 80 countries and live in the coastal areas of more than 140! 

They love travelling so much that they can swim as far as 2,600km between feeding grounds! That’s like driving from Canberra to Alice Springs to grab lunch! That’s a long distance!

3. Green sea turtles have incredible lung capacity

Green sea turtles spend most of their lives underwater. Once hatched, only the females will return to land, and only when it’s time to lay their eggs. With their incredible lung capacity, green sea turtles can stay underwater for up to five hours without breaking the surface for air. 

The human record is less than 25 minutes. 

4. When it comes to laying their eggs, they can be a bit nostalgic

When female green sea turtles reach maturity, at about 20 to 35 years of age, they like to return to the same beach where they hatched. Once there, they use their flippers to dig a hole in the sand, then lay about 115 eggs in it (that’s about nine dozen for the egg-heads among you). 

Green turtle (Chelonia mydas) hatchling breaking out of its egg
Green turtle (Chelonia mydas) hatchling breaking out of its egg © Roger Leguen / WWF

5. The temperature of the sand determines their sex

Whether a green sea turtle is born male or female depends on the heat of the sand incubating the eggs. This is because of something called temperature-dependent sex determination, a type of sex determination found only in reptiles and teleost fish, with warmer temperatures of 29.1°C and above producing females and cooler temperatures producing males.

As climate change causes temperatures around the world to rise, it is also creating a dangerous imbalance in the natural gender ratio of green sea turtles. According to recent research, the offspring of green sea turtles in the northern part of the Great Barrier Reef are born almost entirely female, with males outnumbered by at least 116 to 1. 

If we don’t do everything we can to stop climate change, it’s possible that, in the near future, all green sea turtles will be born female.

The future is female, but not in the usual good way. 

6. A very special tooth

Green sea turtles are born with a very specific tooth known as an ‘egg tooth’ (or caruncle). When they hatch, they use this tooth to break their shells. They then leave their nesting beach and head into oceanic waters. 

7. Green sea turtles used to hang out with dinosaurs

Green sea turtles have existed for more than 110 million years. To put that into perspective, if you think about how long you’ve been around for… they’ve been around for a lot longer. They’ve been around since the time of the dinosaurs! 

8. They age like a fine green wine

Green sea turtles are in it for the long haul, with many living for at least 70 years, sometimes more. Some live to over 100. 

Unlike humans who reach that milestone, turtles who turn 100, unfortunately, don’t receive a letter from the turtle queen or king. As migratory animals, they have no fixed address. Where would the turtle queen or king send it? 

9. Green sea turtles have survived a lot

Having been around for over 110 million years, green sea turtles have survived a lot. They survived the asteroid that killed all the dinosaurs. They survived being hunted for their fat, meat and eggs—though they did experience a massive decline in their population, and now, green sea turtles are facing other existential threats. 

Green turtle hatchling climbing over plastic bottle strewn on the beach, Juani Island, Tanzania
Green turtle hatchling climbing over plastic bottle strewn on the beach, Juani Island, Tanzania © Brent Stirton / Getty Images / WWF-UK

Climate change, habitat destruction, unsustainable fishing practices, invasive species, and pollution are pushing Australia’s globally significant wildlife, land and seascapes to breaking point, causing animals like the green sea turtle to be at risk of extinction. We need to fast-track critically needed environment laws to help protect and restore Australia’s natural environment, as our current laws and the funds required to uphold them are insufficient. But there is hope. 

Right now, the Australian Government is rewriting our national nature laws for the first time in over 20 years, which means we have a small window of opportunity to ensure we get them right. WWF-Australia is asking for the new laws to include a national, genuinely independent Environment Protection Agency and significantly increased funding to help recover threatened species populations and the places they call home.

While the green sea turtle has survived a lot, if these incredible creatures are going to continue to thrive, we need to do everything we can to help them. Add your voice now to help make a difference.

Want to help protect green sea turtles? Here’s how you can get involved.

  • Sign the petition and call on the Australian Government to fast-track strong, enforced environment laws to protect wildlife and the wild places they call home.
  • Adopt a turtle to protect spectacular sea turtles and their ocean home.
  • Discover if threatened animals need protection in your local area by using WWF’s My Backyard tool, and find out how well they’re being cared for.
  • Tune in to Scat Chat with WWF to learn about the weird and wonderful ways that animal scat is being used to help wildlife conservation.