Green turtles over seagrass in Turks and Caicos Islands

Marine turtles: Your questions answered

4 minute read

Ever wondered what the difference between a turtle and tortoise is? Find out as we answer your commonly asked questions about turtles.

What's the difference between a tortoise and a turtle?

To put it simply: all tortoises are turtles, but not all turtles are tortoises. ‘Turtle’ refers to all species in the order Testudines, of which there are 356. This includes tortoises, aquatic turtles like pond turtles and terrapins, and marine turtles.

The main distinction between tortoises and other turtles is that tortoises only live on land – from deserts and sand dunes to mountainsides and tropical forests – while aquatic turtles like terrapins and marine turtles live exclusively or partially in water.

Another difference is that tortoises don’t have paddle-like limbs, known as flippers, or webbed feet, unlike turtles which inhabit water (this helps them to swim more efficiently). Finally, tortoises are herbivores, eating only plants, while turtles tend to be omnivores.

Of these 356 turtle species, there are only seven species of marine or sea turtle. Unlike other turtles and tortoises, marine turtles aren’t able to retract their heads and limbs into their shells.

Green turtles over seagrass in Caribbean UKOTs.jpg

Credit: Peter Richardson

Is a turtle a reptile?

Yes, turtles are reptiles - not amphibians which they’re sometimes thought to be.

Testudines, are one of the four groups of reptiles alive today. They have the typical characteristics of reptiles: they’re vertebrate, are cold-blooded, lay eggs, have scaly skin and breathe using lungs.

Do you get marine turtles in the UK?

Yes, leatherback turtles come to UK and Irish waters each summer to feed on jellyfish blooms. Although they’re not commonly spotted, with nine reported around Ireland and the UK in 2022, there’s a chance you’ll spot one when at the coast over summer – so keep your eyes peeled!

Sometimes, hard-shelled species like loggerheads and Kemp's ridley turtles wash up on UK shores – often after strong winds and storms. These are usually juvenile turtles which have been knocked off course by strong currents. They’re not adapted to our cooler waters so may be in cold shock or injured – if you spot one, consult the Turtle Code and report it immediately.

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What do marine turtles eat?

It varies by species, but marine turtles tend to eat a wide range of foods, such as crabs, fish, shrimps, seaweed and algae. Some species, like Olive ridley and Kemp’s ridley eat jellyfish too, which helps to control jellyfish populations.

Green turtles primarily eat plants such as algae, seagrass and seaweed, becoming mostly herbivorous as they age. This diet gives their fat a greenish colour and is the reason for their name. Hawksbill turtles like eating sea sponges found in coral reefs, using their bird-like beaks to fetch them from crevices.

How long do turtles live?

Although it’s hard to determine the life span of the different species of marine turtles, they do tend to live for several decades, and sometimes up to 50 years! This is partly due to the fact that species of marine turtle can take up to 20 to 30 years to mature, after which they can reproduce.

However, many turtles don’t reach adulthood, with turtle hatchlings under threat from various predators and environmental challenges. This means that the odds of hatchlings reaching adulthood are one in 1,000 to one in 10,000.

Can turtles breathe underwater?

Being reptiles, marine turtles can't breathe underwater, so will rising to the surface to breathe. They can, however, hold their breath for an impressively long time - up to several hours - which means they’re able to stay underwater for long periods of time when searching for food or sleeping.

Turtle in the ocean

Credit: Jesse Schoff

Do turtles have teeth?

No, turtles don’t have teeth – rather, they have strong beaks and strong jaw muscles which they use to eat and break down food.

Loggerhead turtles, which are carnivores, have particularly strong jaws so they can crush hard-shelled prey like clams and sea urchins – this alongside their large heads is how they got they name. Hawksbill turtles, on the other hand, are named for their narrow, pointed beaks and V-shaped jaws, which allow them to extract food from hard-to-reach cracks and crevices.

Do turtles hibernate?

Turtles do not hibernate, with several species of marine turtle instead migrating to warmer waters when it gets cold.

However, they can exhibit a behaviour called ‘cold-stunning’ when water temperatures are too low. During cold-stunning, turtles become lethargic and their metabolic processes slow down, allowing them to conserve energy and endure harsh conditions.

How long marine turtles do this for depends on the species and how cold it is – it may be days or even days weeks before they return to their usual state. Although turtles can recover after a short spell in cold conditions, cold-stunning poses significant risks when endured for longer periods, rendering them vulnerable to predators and various health conditions.

Terrestrial turtles, on the other hand, ‘brumate’, which is similar to hibernation. During brumation, turtles enter a state of dormancy by slowing down their metabolic processes. They tend to do this for up to 10-14 weeks.

Are turtles endangered?

Most of the dangers marine turtles face are caused by human activity. One of the biggest threats to turtles is being accidentally caught by fishing gear, which often leads to death.

Climate change is another major factor, with turtles’ habitats such as reef and seagrass ecosystems being destroyed and coastal erosion impacting nesting beaches, where they lay their eggs.

Rising temperatures caused by climate change are also impacting turtle populations, as the sex of hatchling turtles is determined by the temperature of the egg during incubation. This means that as temperatures rise, so does the likelihood of turtles being born female - making males very scarce and turtle populations vulnerable to extinction.

Other threats include turtles' habitats and nesting beaches being disturbed or destroyed by coastal development. This limits where they can safely feed and nest in, making it crucial to protect these sites on which turtles depend.

Max Gotts - turtle hatchling on beach

Credit: Max Gotts

We’re working alongside partners and communities in the British Virgin Islands, Turks and Caicos, and Montserrat to develop protection and management measures for these species and their environments to ensure a future for these valuable species.

Learn more about our work to protect turtles

Protecting turtles projects