Leatherback Turtle in West Papua

Every day is Turtle Day when you're an ocean campaigner…

When I heard it was World Turtle Day, I hatched a plan. I know that to an international audience 'turtle' covers a multitude of reptile species, but rather than getting all Queens' English-y over what is a tortoise, a terrapin or a turtle, I thought this was a good opportunity to focus in on the seven amazing species that roam our oceans – the sea turtles.

And there are three good reasons: they are awesome; no one will dispute calling them 'turtles'; and six out of seven species are endangered, thanks to us – so they need some love.

So here is everything you needed to know about sea turtles, in a handy, shareable blog.

Sea turtles are ocean wanderers. Females return to the beach they were born on to lay their eggs, but males have no need to ever return to land.

Some turtles are not fussy with their food, but some species really are. Leatherback turtles love jellyfish and hawksbill turtles prefer to eat sponges. Both have adapted to be able to resist stings, spikes, and toxins to let them munch down on their preferred lunch.

Loggerhead turtles have big, strong heads. They need them for crushing and crunching shellfish. Back in Shakespeare's time the word 'loggerhead' was a derogatory word meaning 'blockhead'. Which isn't very nice.

Green turtles are the only vegetarians in the sea turtle world. But when they are young they are less bothered and will eat anything. It's only when they become fussy right-on teenagers that they decide meat is murder.

'Turning turtle' means to be upside down, or belly up. For a turtle on land this is a real problem. For a sea turtle it is merely the backstroke.

The Teenage Mutant Ninja Turtles were probably terrapins. Yeah - Teenage Mutant Ninja Terrapins. Hmm.

Leatherback turtles are the undoubted record breakers. They can travel 10,000 miles each year foraging for food, dive more than 1200 metres deep into the ocean, and range all the way from Chile to Alaska. They are adapted for cold water, warm-blooded, with an insulating layer of fat.

And leatherbacks are HUUUUGE. The biggest one ever recorded washed up on a beach in Wales, was 2.2metres long – that's roughly the size of a double bed. The smallest sea turtles are about 60cm long when adult.

Even the biggest leatherback starts life as a tiny ping-pong ball sized egg laid in a nest on a beach. Baby turtles must make the perilous journey to the sea, without being picked off by predators, which is pretty tough going for something so ridiculously adorable.

When coming onto land to lay eggs, female turtles can be vulnerable to unusual predators. In South America, jaguars are known to prowl beaches looking for a slow-moving meal.

Leatherback Turtle's Eggs in West Papua

Each interlocking segment on a turtle's shell is known as a 'scute'. Oddly, ''s cute!” is what people tend to say when they see a baby turtle too.

In the film One Million Years BC a giant prehistoric turtle terrorised Raquel Welch in a bikini. This awesome Ray Harryhausen monster was based on a real prehistoric turtle, Archelon, which wasn't quite as big in real life. They do say the camera adds ten pounds though…

Sea turtles that graze algae keep coral reefs healthy (which is good news because coral reefs need all the help they can get), and turtles that eat jellyfish help make the beaches safer for humans who don't want to get stung.

In the water, a plastic bag looks like a jellyfish. That's bad news for turtles.

It's not rocket science knowing how best to start protecting turtles - you would protect their nesting beaches and the seas around them – yet growing pressure from human development means turtles are losing out across the world.

Some places where turtles were traditionally hunted for meat and their shells are switching to ecotourism instead. Turtles, like whales, must be worth more alive than dead, right?

Turtles are fantastic ocean ambassadors, but also indicators of the many ways we humans are screwing those same oceans up. Protecting turtles means changing fishing methods, protecting areas are needed for feeding and breeding, and for us to stop treating the ocean as a rubbish tip.

Add your voice to the call for marine reserves

Greenpeace is working on all of those, and actively campaigning for a global network of large-scale marine reserves – areas that are closed to all extractive uses, such as fishing and mining – covering 40% of the world's oceans, which are urgently needed to protect marine species and their habitats and that could be key to reversing global fisheries decline. Such a network would include smaller coastal reserves that could protect turtle rookeries and larger reserves offshore in ocean areas where marine turtles are at greatest risk.

Join us now and share this with your friends to help spread the word.