From the northern coast of Australia to the south coast of England, sea turtles are found across the globe. They play a key role in marine ecosystems, helping maintain the health of seagrass beds and coral reefs.
But of the seven types of sea turtle, three are now classified as endangered and two as critically endangered, largely as a result of habitat destruction, pollution, climate change and poaching.
Today is World Sea Turtle Day, so we thought we'd give these majestic swimmers a bit of love with a selection of our favourite sea turtle images.
Gorgeous photos of sea turtles
Birds are known to sometimes land on sea turtles, particularly when turtles are resting at the surface or on land. This tern might be taking advantage of a resting point, or enjoying the opportunity to look for food (such as small invertebrates or algae) on the turtle's shell.
Baby green turtles face a mammoth journey to return to the sea from their nesting beaches, confronted by many predators along the way.
Green turtles are mainly found in tropical climates – and are endangered, with a decreasing population. While adult green turtles are primarily herbivores, juveniles are known to eat jellyfish and other invertebrates.
The global population of hawksbill turtles are critically endangered, due to habitat loss, illegal hunting for their shells and pollution. Their shells have been traded for centuries, used for jewellery – it's where the term 'tortoiseshell' comes from.
A sea turtle's shell serves as a key form of protection for its vital organs, but it also helps it swim thanks to its streamlined shape.
Along with four other species, leatherback sea turtles have been recorded in the waters around Britain, and are by far the most frequently recorded turtle in the UK. Most other species prefer warmer waters. They get their name from the leathery appearance of their shells.
Sea turtles will often rise to the ocean's surface to warm up, surfacing to breathe every half hour or so before returning to deeper waters to feed.
Flatback turtles are named after their flat shell, which is unlike the curved shell of other sea turtle species. Its outer edges are upturned, giving it a distinct look.
Baby sea turtles face many perils in their early days, particularly in highly populated areas. They can fall into drains, be caught by crabs or even crushed by cars – so sea turtle projects have been developed on nesting beaches to look out for nesting turtles and hatchlings and support their development and help them return to sea.