FAQ
 
Sea Turtle- General

What type of animal is a sea turtle?
What is a sea turtle?
How many sea turtle species exist?
How long have sea turtles existed for?
What was the first turtle?
What are the differences between turtles, tortoises and terrapins?
What species is the smallest?
What species is the rarest?
How long do they live?
What happens to the bodies of turtles that die?
Can sea turtles be kept as pets?
Are there any diseases in sea turtles that are transferable to humans and vice versa?
Where can I feed or touch turtles?
What is the term used to describe a group of turtles?
What is a Male/Female turtle called?
What is a baby turtle called?
What is a turtle’s shell made of?
Do all turtles have shells?
Can turtles remove their shells?
Where can I find more information about sea turtles?


Sea Turtle- Behaviour

How deep can sea turtles dive?
How long can a sea turtle hold its breath? And why do they drown?
How fast do they swim?
What is the fastest speed of a turtle on record?
How long can they stay out of the water?
Do turtles make sounds and/or communicate?
Do turtles sleep?
Do sea turtles have any kind of relationship with other marine life?
Are turtles naturally friendly? Do they fight?
What is cold stunning?


Habitat and Migration

How far south can we meet turtles – and how far north?
Can turtles live in fresh water and salt water?
Which species is most common in the Mediterranean?
Where can you see turtles in the wild?
How do hatchlings and adults locate the ocean?
What is the distance a turtle can travel?


Reproduction

Are turtles monogamous?
How do sea turtles return to the vicinity of their natal beach to nest?
How do sea turtles nest?
Do sea turtles become entranced when nesting?
What do sea turtle nests look like?
How many eggs do sea turtles lay?
What do sea turtle eggs look like?
Do turtles care for their young?
What determines the sex of a sea turtle?
Do mother turtles attend to their nests?
Why do hatchlings emerge together?
Which species nest in the Mediterranean?
Do sea turtles ever lay eggs underwater?
Do sea turtles court before mating?
What are arribadas? What are names and locations of some beaches where arribadas occur?
Do hatchlings bond with each other?
Is there a relationship between body size and clutch size?

Feeding

What do sea turtles eat and do they have teeth?
What kinds of plants or animals do loggerheads eat in the Mediterranean?
What do sea turtles eat and do they have teeth?
What kinds of plants or animals do loggerheads eat in the Mediterranean?
What do turtles drink for liquid intake?


Protection

What are the main threats to Mediterranean sea turtles?
What is the importance of sea turtles? Why try to conserve them?
Are turtles endangered?
Have any species of turtles become extinct?
What is being done to protect turtles?
Does global warming affect turtles?
Where can I get or buy a turtle?
Can I volunteer to help turtles?
I would like to gain experience working with turtles. How can I work with turtles?
How can I find a job that deals with turtles?
How do my donations help turtles?


Communication with other species

Does the turtle have any enemies?
Which species of animals prey on eggs and hatchlings?
What is a Remora?
What are the white organisms attached to sea turtles and their tags?
What species interact with loggerhead sea turtles?

Monitoring/Research/Volunteering

How can sea turtles be aged?
How are sea turtles tracked in the ocean and how long can they be tracked for?
How and why are sea turtles identified?
How do scientists determine how a turtle died?
How are sea turtle nesting beaches and migration routes discovered?
I’m interested in gaining experience doing field research. Can I volunteer to help with the turtle field work?


Sea Turtles-General

What type of animal is a sea turtle?
A reptile. Reptiles are cold-blooded animals, which have existed since Pre-historic times.

What is a sea turtle?
A sea turtle is an ocean dwelling, air-breathing reptile. They have a large shell called a carapace, four strong, paddle-like flippers and like all reptiles, lungs for breathing air. The characteristic beak-like mouth is used to shear or crush food. Their flippers are perfectly adapted for marine life. They spend the majority of their lives at sea, and exit only to bask (green sea turtles in Hawaii) or to nest (only the females). Sick sea turtles suffering from “cold stunning” for example may also be washed ashore.

How many species of sea turtle exist?
There are eight extant species:-

The Loggerhead (Caretta caretta)
Green sea turtle (Chelonia mydas)
Black sea turtle (Chelonia agassizii)
Hawksbill (Eretmochelys imbricata)
Olive ridley (Lepidochelys olivacea)
Kemp’s ridley (Lepidochelys kempi)
Leatherback (Dermochelys coriacea)
Flatback (Natator depressus)


How long have sea turtles existed for?

Approximately 230 million years. Present day species have evolved from those living in Prehistoric times.

What was the first turtle?
The first turtles appeared in the late Triassic period. The first sea turtles appeared in the late Jurassic era, approximately 65 million years ago. One of the oldest fossilised sea turtles is the Archelon sea turtle.

What are the differences between turtles, tortoises and terrapins?

“All tortoises are turtles, but not all turtles are tortoises.
All terrapins are turtles, but not all turtles are terrapins.
Some turtles are just turtles.”

The World of Turtles and Crocodiles

Turtle - Water-dwelling, without claws and tend to have webbed feet for swimming. Sea turtles are especially adapted for aquatic life with flippers and stream-lined bodies that rarely leave the ocean (except to nest).

Other turtles live in fresh water such as ponds and lakes. They swim but can also climb onto the bank or logs to bask in the sun. In the winter they can burrow into the mud, where they go into torpor until warmer weather.

Terrapin – Mostly water-dwelling creature with claws. Terrapins spend time in both land and water, but cannot be far from water- along rivers, ponds and lakes- often in brackish, swampy areas. The word terrapin is derived from the Indian word meaning ‘little turtle’.

Tortoise – A tortoise is a land-dweller and eats low-growing shrubs. They have round and stumpy for walking on land. They live in hot, dry habitats and dig burrows to escape the hot sun.

How big was the largest sea turtle ever recorded?

The largest species of sea turtle was the Archelon, which measured 7m in length and lived in Prehistoric times. Today, the largest living species is the Leatherback. There are 2 sub-species, the Pacific Leatherback and the Atlantic Leatherback. The Atlantic Leatherback is slightly larger than the Pacific population. Leatherbacks measure an average of just less than 2m in carapace (shell) length. The largest Leatherback ever recorded was a male found stranded (washed ashore) on the Welsh coast in 1987. He measured almost 3m (291cm) from tip to tail and weighed 970 kilos.

Which species of sea turtle is the smallest?
The Kemp’s ridley sea turtle is the smallest species, measuring between 61 – 76cm carapace length and weighing approximately 36 – 45kg.

What is the rarest of all sea turtles?
The Kemp’s ridley sea turtle is the rarest species. Recent estimates suggest there may be only 5,000 adult females, which survive today. Numbers declined to an all time low of approximately 550 adult females in 1986. These turtles nest primarily on one beach in Mexico.

To increase their numbers, Scientists made efforts to establish a new nesting population in Texas by transplanting eggs from Mexico into sand in Texas and “head starting” hatchlings through raising them until they reached a size large enough to limit the likelihood of predation.

How can sea turtles be aged?

Patterns of growth rates in sea turtles have been difficult to assess, mainly because of a lack of methods available to age them. Techniques have been developed more recently that estimate age from the number of growth layers of bones. The humerus, one of the forelimb bones, gives the best indicator of age as they retain the greatest number of growth layers. There are limitations using growth layers for aging. In mature turtles, early growth layers are re-adsorbed, growth rates may not be constant and they are not necessarily annual.

Growth studies have been conducted where a fluorescent chemical has been injected into adult sea turtles. When these turtles are located years later, the humerus has been examined beneath a microscope during biopsy, and growth layers are clear and countable.
Unfortunately, this technique has not been used on young turtles, so unless the turtles age is known for definite, these techniques will only ever provide estimates. Techniques for using bones to determine age are complicated, but are described in detail in articles included in the Bibliography. Currently there is no accurate technique available for aging sea turtles only methods for estimation are described in literature.

How long do they live?
No exact information is available. It is known that they are long-lived species, but only estimates are available. Leatherbacks may live for 30 – 50 years, whilst the smaller species may live for up to 75 years or more.

What happens to the bodies of turtles that die?
What happens to their bodies depends on which environment they die in. Of those, which die in the ocean, only a very small percentage wash ashore. The majority sinks to the bottom of the ocean where they are fed on by an array of other animal life including fish and worms, which strip the bones of dead flesh. Those, which die on land, may be eaten by a variety if organisms including birds, such as Vultures, ants, fly larvae, etc. Their bodies provide a good source of food to these creatures and the bones help fertilize the sand and provide it with Calcium.

How deep can sea turtles dive?

Leatherbacks can dive to a depth of more than 1000m in search of their prey, jellyfish. The smaller species are unable to dive to such great depths. The Leatherback is adapted to deep dives because of its unique morphology. Unlike other sea turtles, the Leatherback lacks a rigid breastbone/ lower chest, allowing the chest to collapse during deep dives. There is a large amount of oil in the skin and the Leathery shell absorbs Nitrogen, reducing problems arising from decompression during deep dives and resurfacing.


How long can a sea turtle hold its breath? And why do they drown?

As sea turtles are air breathing reptiles, they need to surface to breathe. Sea turtles can hold their breath for several hours, depending upon the level of activity. A resting/sleeping turtle can remain underwater for over 4-7 hours. Recent research has shown that some turtles can even hibernate in the sea for several months! However, a stressed turtle, for instance entangled in fishing gear, quickly uses up oxygen stored within its body and may drown within minutes through panic.

Can sea turtles be kept as pets?


All species of sea turtle are classified on the IUCN Red List as threatened or endangered. As such, it is illegal to handle them or to keep one as a pet. Specific permits (under CITIES) are required to handle a sea turtle or its products and to house them legally (usually in Aquaria or Rescue Centres, which should provide adequate facilities to properly care for them). It would be very difficult for a member of the public lacking training and required facilities to correctly care for a sea turtle. Anyone discovered by the authorities to be keeping a sea turtle as a pet or in insufficient conditions is liable for prosecution.

Do turtles live shorter in captivity?

Leatherbacks cannot survive for very long in captivity. They are big deep ocean dwellers and continually bump into the sides of whatever enclosure they are held in.

Depending upon the conditions in which other species are maintained, they may live quite well, but usually sea turtles are housed in large numbers together. Being solitary animals, they bite each another and grow too quickly compared to natural conditions due to being fed on a high protein diet (often the wring diet in the case of Green turtles) and contact diseases.

Because sea turtles are wild animals, it is better to leave them in the wild, in their natural environment, than to keep them in captivity under unnatural conditions.

Are there any diseases in sea turtles that are transferable to humans and vice versa?

Numerous bacterial infections have been identified from sea turtles. One type of bacteria that is transferable between turtle and humans is Salmonella, present in all turtles (land, fresh water and sea turtle species). It is advisable when handling a sea turtle to wear latex gloves or if not available, to thoroughly wash hands both before handling the turtle to rid of any bacteria on our hands, and after handling to rid of any bacteria on the turtle. Sea turtles are highly sensitive creatures that are well adapted to their sea environment, but are easily stressed when they come into contact with man made pollutants, such as agricultural pesticide runoff. Currently, one of the biggest threats to Green turtles in particular is a disease called "Fibropapillomatosis" or "FP" for short, although it has more recently been observed in other species of sea turtle. This is directly linked with areas of high levels of human activity and high levels of pollution.

Where can I feed or touch turtles?
Sea turtles are wild animals and although they are kept in captivity in some Aquariums, they should not be touched or fed unless sick or injured and in need of captive care. Feeding and handling should only be done by trained individuals. Once the turtle has been successfully rehabilitated, it should be released back into the wild and will hopefully not come into contact with humans again.

Wild turtles should not be touched or fed. They may be resting, swimming or nesting when you see them, but should be left to their own devices. It is possible to touch a turtle when volunteering on a field project, but minimal handling is preferred.

How fast do they swim?
Sea turtles have been recorded swimming at speeds of 30mph (in bursts), but generally they swim at around 4 – 5mph.

What is the fastest speed of a turtle on record?
A Pacific Leatherback reached the fastest speed on record for a sea turtle. The turtle reached a swimming speed of 22 mph as it attempted to avoid a predator.

How long can turtles stay out of the water?
Nesting turtles can stay out of the water for several hours. Sometimes sea turtles nest during the daytime and if the weather gets hot and they are unable to return to the sea, they dehydrate and suffer from heat stress. This may lead to death.

How long can they stay under water?
When active, sea turtles breathe every few minutes at the surface of the water. When less active, e.g., when resting, they surface to breathe every couple of hours or so. When sleeping, they may remain under water for 4 or more hours. If stressed, for example, when caught in a fishing-net, they quickly utilize their oxygen and drown. This happens because they can only breathe out of water.

Do turtles make sounds and/ or communicate?
I have heard them making sounds, but usually only those associated with breathing. All sea turtles are audible breathing when they are moving on the nesting beach and when they have contractions during egg laying. Nesting Leatherback’s also sound as if they are “burping” sometimes! I haven’t heard turtles make any other sounds, even when being predated on by other animals.

Richard Reina who is an American sea turtle expert was asked this question in an interview. His answer was that “we don’t know for sure if they communicate, but we think they probably communicate by sound and by sight. They make sounds that one another can hear, and they find each other by listening.”

Do sea turtles sleep?
Yes. They sleep by floating at the surface of the water if in deep water, often amongst Sargassum weed or other floats as hatchlings. They sleep with their nostrils above the water, so they can breathe. In shallower waters, such as on coral reefs, they often sleep in crevices by jamming themselves beneath coral or rocks. Here they must surface every hour or so to breathe, before returning to sleep some more.

Do sea turtles have any kind of relationship with other marine life?
The only relationships I am aware of are those with species, which co-exist with them, e.g., Remora fish, barnacles, crabs, cleaner fish, etc.

Are turtles naturally friendly? Do turtles fight?
Turtles are naturally inquisitive and will explore people in their own environment and when in captivity. They do not like being closely approached in their marine environment however, and will quickly swim away when they feel harassed or threatened.

They are solitary animals and when in captivity they will fight (bite) each other.

What is a Male/ Female turtle called?
There is no name given to a male or female turtle. They are just referred to as turtles.

What is a baby turtle called?
Baby turtles are called “hatchlings” because they have recently “hatched” out of their eggshells.

What is the term used to describe a group of turtles?
There is no widely used term for a group of turtles, although some call a group a “bale” or a “flotilla”.

How can you tell the difference between a male and a female turtle?
Turtles cannot be sexed until they reach sexual maturity. At this stage, they can be sexed based upon the length of their tail. A male’s tail extends way past the back of the carapace. A female’s tail is much shorter and only extends a little past the end of the carapace. A male’s plastron (under shell) is also slightly indented/ concave.

What is cold stunning?
Cold stunning describes a condition, which sea turtles enter when they experience extremely cold water temperatures (7 - 10º), which makes them lethargic and unable to function normally. They float on the waters surface and are unable to dive and feed. In severe cases they may die.

This is a juvenile loggerhead turtle that was found as a "cold-stun" in winter in North Carolina, and was brought into captivity for rehabilitation before eventual release.
© 2003 Matthew Godfrey

What is a turtle's shell made of?
Individual bones covered with Keratin form the shell of a sea turtle.

Do all turtles have shells?
Yes, although the type of shell differs amongst species. Leatherbacks have a leathery shell, which isn’t a hard, solid shell like other sea turtle species have. A Leatherback’s shell also has no ‘scutes’ or plates.

Can a turtle remove its shell?
No. A sea turtles shell consists of bone from fused ribs and vertebrae (back bones) covered in Keratin (the material human finger nails are made of). Although on the outside of the turtle, the shell is very much alive and forms the turtle’s only form of from would-be predators’.

Where can I find more information about sea turtles?

A good place to start is right here at EuroTurtle and then on the Internet. You can search for most subjects on search engines such as “Google”. Some good websites include “Turtle Trax” and “The Marine Turtle Newsletter”, which is a monthly newsletter about sea turtles, also available on the Internet. Otherwise, there are literally hundreds of books available on sea turtles. A good beginners book is by Jeff Ripple entitled “Sea Turtles” (see reference list below for the full reference).

Habitat and migrations

How far south can we meet turtles – and how far north?
The sea turtle with the widest distribution of any reptile is the Leatherback. It has been recorded as far South as Antarctica and as far North as Norway.

Can sea turtles live in fresh water and salt water?

When in captivity, sea turtles should be maintained in water with a salinity level falling within a range of that of normal, natural, incoming seawater. Short periods of holding sea turtles in fresh water can be tolerated and are useful when prescribed by a veterinarian, e.g., to remove parasites and fouling epibiota such as barnacles. However, prolonged periods in fresh water should not be encouraged. Sea turtles are meant for life in the sea, so they do best in an environment with a similar salinity.

Species is most common in the Mediterranean?


The Loggerhead is the most common species. The largest nesting assemblage is on the Greek Island of Zakynthos, on a private nesting beach of less than 600 metres. This beach is the most densely nested Loggerhead beach in the World, with almost 200 emergences recorded every night during peak nesting season!

Where can you see turtles in the wild?
Sea turtles inhabit most temperate, tropical and sub tropical seas and oceans of the World. They can be found swimming out in the ocean, but more commonly near shore during their breeding seasons. The Greek Island of Zakynthos is a good place to see sea turtles near shore, as is Barbados.

How do hatchlings and adults locate the ocean?
Sea turtles are ‘phototactic’, meaning that they are attracted to light, and so head towards the brightest light, which in nature is the moonlight reflecting on the sea, or the white surf line. They orientate themselves towards the seaward (bright) horizon. Turtles avoid shadows, including vegetation at the back of the beach, places where danger could lie.




Communication with other species

Do sea turtles have any enemies?
Sea turtles have many enemies. Their main threat is humankind. We are responsible for damaging and destroying their nesting beaches, polluting their habitats (their sea’s and ocean’s), which results in them contracting diseases such as Fibropapillomatosis. We slaughter them for their meat, shells, bones, and other by-products. We harvest their eggs, kill hundreds of thousands of them annually through catching them accidentally in our fishing nets, injure or kill them through incidental boat strikes, etc.

Other animals and insects predate on them at different life stages. Ants, crabs, gulls, raccoons, dogs, fish, etc. all feed on sea turtles during their various life stages.

Which species of animals prey on eggs and hatchlings?
The animals that prey on hatchlings in the Mediterranean depend on the location but include seagulls, crabs (particularly Ghost crabs), red foxes and fish. In addition to these natural predators, stray dogs also pose a threat.
Eggs are predated on by red foxes, rats, raccoons, dogs, and insects, including various species of fly larvae (maggots). Birds and crabs become predators following exposure of the eggs by the mammals mentioned above.

What is a Remora?

A remora is a pelagic (open ocean) fish found in warmer areas. Remoras attach themselves to sea turtles and other marine animals through a suction disc located on the top of their head. As they lack a swim bladder, attaching themselves to larger marine animals enables them to travel through the oceans. They are not parasites. They remove parasitic organisms and pose no threat to their host. For this reason, they are referred to as a type of “cleaner” fish.

What are the white organisms attached to sea turtles and their tags?

The white organisms may be a type of barnacle (a crustacean, which at the adult stage attaches itself to a solid surface). They are often found attached both to the hard and soft parts of a sea turtle and/ or their flipper tags. Biologists are researching into whether barnacles negatively affect sea turtles. Their presence can make tag reading difficult, or impossible.

What species interact with loggerhead sea turtles?

Although sea turtles are solitary animals, Loggerheads have been known to visit cleaning stations where omnivorous fish feed on the micro-organisms found on turtles soft and hard body surfaces. Fish also feed on resting turtles.

Reproduction

Are turtles monogamous?
No. Turtles mate with numerous turtles during the course of a breeding season.

How do sea turtles return to the vicinity of their natal beach to nest?
There are several theories as to how they locate this area, but none have yet been proven. The most common theories are:
Theory 1) Detection and utilisation of the Earth’s magnetic field:
Sea turtles may have the ability to detect the angle and intensity of the Earth’s magnetic field and utilise these characteristics to determine their latitude and longitude, enabling navigation of hundreds, even thousands of kilometres. Recent studies confirm the ability of sea turtles to detect the Earth’s magnetic fields. Current research is determining whether they use this ability to navigate.
Theory 2) Natal homing/ imprinting (Carr):
It is widely believed that hatchlings imprint the unique qualities of their natal beach whilst in the nest and/or during their first trip from the nest to the sea. Beach characteristics used may include smell, low-frequency sound (possibly the noise of the surf), magnetic fields, the characteristics of seasonal offshore currents and celestial cues.
Theory 3) Social facilitation (Hendrikson):
Female turtles may follow older, experienced nesting turtles from their feeding grounds to the rookery (breeding site).

The nesting process consists of 8 stages. Firstly, the turtle emerges from the sea and ascends the beach, searching for a suitable nesting site (somewhere dark and quiet). Once at the chosen nesting site, she begins body pitting (BP). Using all four flippers, she gets rid of dry surface sand beneath her which would otherwise fall into her egg chamber (EC) (forming a depression). Following BP, she commences digging her nest (DN).

Now she uses only her rear flippers, alternately, like hands, and scoops out flippers full of damp sand. She scoops sand in one flipper and rests this flipper on the surface, before throwing sand from her other flipper to her side.

She uses her emptied flipper to remove more sand from inside the EC and flicks excavated sand from her other flipper. When she can reach no deeper, she pauses and begins contractions, her rear flippers raising off the sand’s surface simultaneously. Soon she begins laying eggs (LE). Following each contraction, she drops between 1-4 eggs into the EC in quick succession.

The eggs will almost fill the EC. Once her clutch is complete, she closes the nest (CN). Using her rear flippers in the same way as she did during the DN process, she places sand inside the EC, until the eggs are completely covered. She gently pats the damp sand on top of her eggs, using the underside of her shell (plastron). The camouflaging (CA) process now begins. Slowly moving forward, she throws dry, surface sand behind her. This is an effort to conceal/camouflage the location of her eggs from would-be-predators. She may travel in this way for over 3m. When the turtle ceases CA, she descends the nesting beach, and heads for the sea. Lastly, she enters the sea, and swims away from the beach.

Do sea turtles become entranced when nesting?
No. It is a commonly stated myth. The nesting process is difficult, tiring and time consuming. As sea turtles flippers are well adapted for their marine life, they are not well adapted for use on dry land, making movement clumsy. Although turtles will abandon the nesting process if they are disturbed and feel threatened, due to the effort involved, once egg laying (ovipositing) has begun, they are less likely to abandon their nest. However, if ovipositing has not begun, they are more likely to abandon nesting efforts, and return to the sea, in which case they will attempt nesting later that same night or within 1-2 days of the original attempt.

What do sea turtle nests look like?

Turtle nests are “flask” shaped; narrow and elongated at the top and wider and more rounded at the bottom. The depth of a nest depends upon the species, with larger turtles like the Leatherback constructing nests between 80cm-over 1m deep. Smaller species such as the Olive Ridley construct shallower nests to a depth of approximately 30cm. A turtle will dig down into the sand until she can reach no deeper. The nest of a Leatherback differs from that of other turtles in that instead of being rounded at the bottom, it is almost rectangular in shape.

How many eggs do sea turtles lay?
Depending on species, they may lay clutches containing on average 50-160+ eggs, and may lay more than one clutch in a season. Flatback turtles (endemic to Australian waters) lay the smallest clutches (approximately 50 eggs per clutch). Hawksbill turtles lay the largest clutches, which may contain over 200 eggs!

What do sea turtle eggs look like?
They are the size and shape of ping-pong balls with a soft shell. Usually eggs are spherical in shape, although occasionally, they are mis-shaped (elongated or adjoined with calcium strands). Some sea turtles lay small infertile eggs, which only contain albumin (egg white). The Leatherback turtle lays some of these small eggs in every clutch, whereas the other species of sea turtle lay these eggs infrequently.

Do turtles care for their young?
There is no parental care given to young turtles from their Mothers. Mother turtles simply lay their eggs on the nesting beach and depart after concealing their nests from would be predators. The young hatch out and have to fend for themselves as soon as they depart their nest.

What determines the sex of a sea turtle?
The temperature of the nest determines a hatchlings sex. This is called ‘temperature -dependent sex determination’ (TSD). Warmer temperatures produce mostly females, and cooler temperatures produce a majority of males. There is a pivotal temperature that produces an equal ratio of males and females. The temperature determining sex ratio differs between species and nest locations.

Do mother turtles attend to their nests?
No, once a nest has been completed, the female never returns to it. The eggs and resulting hatchlings are left to fend for themselves and locate the water upon emerging.

As hatchlings are so small, and the egg chambers from which they emerge are deep (between 30cm to 1m+ depth, depending on species), it would be impossible for a single hatchling to escape from the chamber alone. As hatchlings break free from their eggs inside the egg chamber, they stimulate other hatchlings to emerge from their eggs simultaneously.
Once most hatchlings have emerged from their shells, they climb on top of the discarded eggshells. Hatchlings higher up the egg chamber scratch down sand from above and around them. The hatchlings make use of this sand and the discarded eggshells, like an elevator and ascend the egg chamber. Hatchlings beneath push those above out of the egg chamber. They emerge en masse or in small groups. Emerging together increases the chance of survival as many hatchlings can overwhelm would-be predators. A single hatchling would be an easy meal.

Which species nest in the Mediterranean?
Three species are found in this region: Loggerheads, Greens and Leatherbacks, but only Loggerhead and Green turtles nest here. The Leatherback is an occasional visitor to the waters of the Mediterranean, but does not nest there.

Do sea turtles ever lay eggs underwater?
Sea turtles lay eggs (oviposit) on sandy beaches. Their eggs breathe air through their membranes and so cannot survive if they are continuously covered with water. Nesting turtles sometimes abandon nesting if they are disturbed and are scared back to sea, but they usually try to nest again elsewhere later that night or within 1-2 days of the failed attempt. Turtles disturbed during several nesting attempts may abort their eggs in the sea if they can’t carry them any longer. Once a clutch of eggs is ripe, they must be deposited, to allow for development of another clutch. Captive turtles have been known to drop eggs into the water.

Do sea turtles court before mating?
Most sea turtle studies have focused on land when the females nest, for ease of observation. Little research has been conducted in the sea, so there is limited knowledge on their behaviour in the water. It is known that sea turtle “courtship” usually occurs offshore the nesting beach. Males approach any female turtle, and occasionally logs, and scuba divers who resemble the females! Several males compete for the same female. She mates with them during the breeding season, and has the ability to retain their sperm from one season to the next. She uses the sperm of several males to fertilise her clutches, increasing the gene pool. Further studies are needed on courtship behaviour.

What are arribadas? What are names and locations of some beaches where arribadas occur?
"Arribada" means 'arrival' in Spanish. It describes a mass-nesting event of the ridley sea turtles. Such an event occurs when large numbers of turtles have gathered off shore to form a "flotilla". Then they emerge from the sea en masse and nest synchronously over the course of 3 - 7 days.
There used to be arribadas with 40, 000 + turtles on one beach on one day in Mexico in the early 1960's. Sadly today, although they do still occur, numbers have decreased dramatically, mainly through poaching, to only a few thousand nesting females. In other areas numbers have dwindled to the point where arribadas no longer occur on beaches that used to experience them.
Today, arribadas occur in places such as Ostional, Costa Rica, Rancho Nuevo, Mexico and Devi, India.

Do hatchlings bond with each other?
Sea turtles are solitary animals. Although they hatch together in large numbers, and make use of each other to ascend the nest, they enter the sea alone. They do not leave a beach in a group, but are transported by the waves to wherever the current flows. Sometimes they may be found together floating in a 'sargassum', or some other 'raft', however they remain solitary. Sea turtles may congregate at feeding grounds or developmental habitats, but solely for the purpose of feeding on the food sources present. When turtles are held in captivity as hatchlings, they do not appear to 'bond' with each other. When larger turtles are held in one tank they can be aggressive towards one another and will bite.

Is there a relationship between body size and clutch size?
The relationship differs amongst species.
Flatback turtles (endemic to Australia) produce small clutches, much smaller than those of other turtle species. This is likely due to their shell shape being flatter and therefore narrower than other sea turtle species. Soft shelled Leatherbacks produce relatively small clutches compared to the smaller hard-shelled sea turtles, they are the largest of all sea turtles. Clutch size has been found to have a positive relationship with shell size in Green turtles and in some populations of Loggerheads. With Olive ridleys there is a positive relationship between clutch size and shell size. This relationship makes sense because the larger the body size, the more space there is for eggs to develop internally. Sea turtles basically become egg producing machines during the breeding season, and have several clutches developing at a given time. However, body to clutch size relationships vary, even within a nesting season a turtle may lay clutches of varying size.


Feeding

What do sea turtles eat and do they have teeth?
Each species feeds on a diet specific to that species. For example, Loggerheads feed mainly on hard-shelled organisms such as lobsters, crustaceans, and fish, Green turtles prefer sea grasses and Leatherbacks feed exclusively on jellyfish. Plastic bags are often mistaken by turtles for jellyfish and are eaten. Plastic may accumulate inside a turtles gut and make the turtle feel full, when in fact it is hungry, this may result in starvation. Plastic may also lead to suffocation. Although Green sea turtles jaws are serrated, all sea turtles jaws lack teeth. The Leatherbacks jaw has 2 prominent “cusps” on the upper jawbone, distinguishing it from the other turtles.


What is the diet of sea turtles in the Mediterranean?
Loggerhead turtles generally feed on both plants and animals but they are mainly carnivorous. Their diet contains various species of algae, including Sargassum weed, which as hatchlings they also utilize as a 'float'. After emerging from their nests, leaving the beach, and moving into the open sea, they drift into deeper water which carries them into the Sargassum weed. This weed provides them with cover from would be predators and collects floating objects including zoo and phytoplankton which they feed on.
Loggerheads jaws are adapted to eating hard objects, such as crabs, barnacles, Lobster, bivalves, whelks, conchs and sea urchins. They can easily crush the hard shells of these animals. They also feed on sponges, jellyfish, shrimp, fish and fish eggs, as well as on a variety of plants, so they are classed as generalists.
Unfortunately, loggerheads also eat waste products such as plastic and rope, which they mistake as food items.

What do turtles drink for liquid intake?

All sea turtles drink only seawater all of their lives. They have special glands behind each eye, called "salt glands" that they use to get rid of all the salt from the seawater. When they drink the salt water the salt enters the blood and is transported to the salt glands that then produce a solution that contains about twice the concentration of salt as the seawater they drank. This concentrated solution comes out from the corner of the eye as salty tears and is washed away. In this way they can drink seawater, get rid of the salt in their tears and have about half the amount of seawater left as freshwater to use for their physical requirements. Other animals like sea birds and sea snakes can do this too, but sea turtles are the best at it.
Answer from Richard Reina (Drexel University) on www.seaturtle.org

Protection

What are the main threats to Mediterranean sea turtles?
Anthropogenic (human caused) threats are numerous and include degradation and/or loss of nesting habitat, sand compaction through driving vehicles on nesting beaches, sand raking and/or removal, marine pollution and disease, incidental catch by fisheries (specifically shrimp trawlers and long lines), boat strike by speeding boats, tourism development, etc. Currently, the biggest threat to sea turtles is fishing activity, with incidental catches of thousands of turtles each year.

What is the importance of sea turtles? Why try to conserve them?

Sea turtles are one of the longest living groups of animals to have ever existed, having far outlived the Dinosaurs. They have existed for approximately 200m years, and survived perfectly well until human activities placed them under increasing pressure. They act as environmental indicators. When populations are healthy (disease is uncommon), it reflects on the health of their marine habitat. They feed on a variety of organisms, e.g., Hawksbills eat sponges and corals, providing space for reef colonisation by other organisms, increasing species diversity. They feed other organisms, e.g., insects, crabs, fish, etc. which prey upon them at various life stages. Nutrients turtles produce through digestion feed other organisms. They provide a habitat for an array of animals including cleaner fish, and various barnacle species, some of which are exclusive to sea turtles. Sea turtles are an intricate part of their ecosystem. If they are wiped out, many organisms dependant upon them will also be affected.

Sea turtles make substantial nutrient and energy contributions to beaches, promoting plant growth, stabilising beach and dune systems. Green sea turtles graze seagrass beds, increasing the productivity of those areas. Leatherback turtles are major jellyfish predators, providing natural ecological control of jellyfish populations. If the decline in sea turtle populations is allowed to continue, it could have severe consequences on many marine and terrestrial plant and animal species that depend on sea turtles for their survival.

Furthermore, sea turtles are a flagship species, which means they are a species chosen to represent an environmental cause conserving the marine ecosystem and wildlife. Chosen for their charismatic nature, distinctiveness and vulnerable status, sea turtles engender public support and thus assist leverage of the entire ecosystem and associated species.

Are turtles endangered?

Out of the seven types of sea turtles in the world, unfortunately six of these are on the redlist as either endangered or critically endangered.

According to the IUCN Red List

Loggerhead Caretta caretta- Endangered
Green turtle Chelonia Mydas- Endangered
Hawksbill Eretmochelys imbricate- Critically Endangered
Kemp’s Ridley Lepidochelys kempii- Critically Endangered
Olive Ridley Lepidochelys olivacea- Vulnerable
Leatherback Dermochelys coriacea- Critically Endangered

For more information on IUCN Red List data visit: http://www.iucnredlist.org/

Have any species of turtles become extinct?

Not since Prehistoric times have any turtles become extinct, however modern sea turtles such as the Kemp’s Ridley may be very close with only several hundred remaining.


What is being done to protect turtles?
There is a global sea turtle community of over a thousand specialists; these dedicated individuals and organizations often dedicate their life work to monitor and assessing nesting beaches and through rehabilitation to ensure that sea turtles continue to grace our seas. Research projects, public awareness campaigns, environmental education, nesting beach assessment and more all contribute to disseminating and propagating information about the importance of conserving sea turtles.

Does global warming affect turtles?

Yes, global warming will have a significant impact on the resilience and sustainability of sea turtle populations.

Visit our Sea Turtles and Global Warming section for more information: Sea Turtles & Global warming


Where can I get or buy a turtle?
It is possible to purchase tortoises or terrapins from many pet stores around the World. They should only be purchased if proper care can be given and husbandry requirements can be well met.

Under CITIES (The Convention on International Trade in Endangered Species of Wild Fauna and Flora), it is illegal to touch or keep a sea turtle, unless you have specific permits which give you permission to do so.

Only a few Aquariums, Zoo’s and Rescue/ Rehabilitation Centres are permitted to maintain sea turtles for their care and public display.

Contact British Chelonia Group: http://www.britishcheloniagroup.org.uk/

Can I volunteer to help turtles?
Yes. There is hundreds of sea turtle research and conservation projects around the World, which depend upon volunteer assistance for donations of both time and money. MEDASSET is such an organization. Please email us at this address if you would like to volunteer with us: - [email protected]

EKAD, a Turkish NGO has pioneered volunteering on sea turtle nesting beaches in Turkey so visit: www.ekad.org and contact: [email protected].

Otherwise, Google will bring up an array of such projects if you search on the Internet.

I would like to gain experience working with turtles. How can I work with turtles?

To gain experience and hands-on experience with sea turtles you could start with a volunteer programme that works directly with sea turtles. Once you gain more experience and knowledge you could apply for a seasonal position, often advertised on the C-TURTLE list serv.


How can I find a job that deals with turtles?

The best place to start is SeaTurtle.org or http://www.seaturtle.org/jobs/ as it is the primary website that supports research and conservation efforts in the sea turtle community.

How do my donations help turtles?

Without donations and generous individuals, research, monitoring, public awareness and rehabilitation efforts would not be able to be sustained. Your donations help to sustain these efforts so crucial in ensuring that scientific knowledge and public consciousness continues to grow.

Monitoring/research

How are sea turtles tracked in the ocean and how long can they be tracked for?
Researchers track sea turtles through a process called “satellite telemetry”. A transmitter (small computer) is attached to the turtle’s carapace (on hard shelled species) or is worn as a ‘backpack’ (fastened around) a Leatherback. The transmitter emits signals of information to an orbiting satellite when the turtle surfaces to breathe or bask. The information in the signals is de-coded prior to being forwarded to receiving stations on Earth, and then it is sent to the researchers computer as a dataset. This data provides information on the turtle’s location, number of dives during the last day, length of the most recent dive, water temperature, etc. Data received over a period allows for tracking a turtles movement patterns and swimming speed. Usually, satellite transmitters are attached to gravid (egg bearing) females that come ashore to nest. Tracking has provided important information on migration routes between breeding and foraging (feeding) habitats. Length of tracking depends upon how long the device remains on the turtle (they may be knocked off or fall off) and on battery life. Tracking usually continues for 6-10 months, although cases have been reported exceeding 2 years.

How and why are sea turtles identified?
Both external and internal markers (tags) are used to enable the identification of a specific individual. External tags are made from metal (monel or inconel) or plastic. Internal tags are called “Passive Integrated Transponder tags” or “PIT tags”. These are microchips consisting of metal and glass. Both external and internal tags display a unique series of letters and numbers, a bar code, eg, ZA214. External tags are clipped onto the turtles’ flipper(s), and are clearly visible to the eye. On the back of flipper tags is the address of the organisation applying the tags. Tags found can be returned with details of date and location when found together with information on the turtle, e.g., whether it was nesting, dead, etc. PIT tags are more expensive and only visible through the use of expensive scanning equipment, which when held over a PIT tag, displays the tag code. Only one PIT tag is needed for each animal and is injected into the turtles shoulder muscle. They are more secure than external tags as they cannot fall off and get lost. By using tags information can be collected on where the turtle was tagged, the number of nests constructed in a season, growth rates, fecundity, etc.

How do scientists determine how a turtle died?
Cause of death can be determined by conducting a ‘necropsy’. This is a turtle’s autopsy. By removing the outer shell of the turtle, the inner organs can be studied in detail. Although external trauma may be obvious through direct observation, e.g., shell breakage, limb amputation, bite marks, etc., necropsies allow observation of otherwise unseen, internal trauma, e.g., disease, refuse presence (plastic), etc.

How are sea turtle nesting beaches and migration routes discovered?
Discovering potential sea turtle nesting beaches has been a component of MEDASSET's work in the Mediterranean for over 25 years now in countries such as Libya, Lebanon, Syria and Egypt. Sea turtles select their specific nesting site through a complex procedure involving a multitude of factors, including many natural ones (e.g. geomorphology, beach inclination, moisture content, sea and sand temperature, sand compactness). The process of finding nesting beaches involves scientific assessments of beaches, investigating the many natural factors and assessing whether human impact could be a deterrent (presence of boats, lights, noise, pollution, development etc.). Speaking with the local community and fisherman can provide insight into whether nesting occurs now or whether it has in the past.
Sea turtle's migration routes can be found using satellite tracking from an electronic transmitter fitted on the turtle's carapace. To see some sea turtle migration routes please visit: http://www.seaturtle.org/tracking/

I’m interested in gaining experience doing field research. Can I volunteer to help with the turtle fieldwork?

Yes there are many field research on sea turtles being carried out around the world some good places to start include the below organizations:

  • Costa Rica has the most structured volunteer programmes with the huge amount of sea turtles voyaging to their nesting beaches every year. This of course includes the leatherback sea turtle, a most incredible sight to see! I would foremost suggest CCC’s volunteer programme: http://www.cccturtle.org/volunteer-research-programs.php
  • In Brazil, Project Tamar accepts volunteers: http://www.gvi.co.uk/pages/projectDetail.asp?expedition=49 . Project Tamar has been enormously successful in Brazil by turning sea turtle poachers and fisherman into nesting guards and educators! This innovative approach has now been adopted around the world.
  • If you would like somewhere closer to Europe, visit EKAD’s volunteer program on the nesting beaches of Turkey: http://www.ekad.org. Or ARCHELON on Zakynthos, Greece has volunteer programs or just visiting the nesting beaches will allow you to spot a loggerhead sea turtle.
  • For an excellent online resource check out http://www.seaturtle.org/links/Jobs/Volunteer/. This page has sea turtle programs in Cuba, Brazil, Australia, Ecuador and anywhere these majestic creatures roam.


References

Chelydra.org (Turtle Pre history)
http://www.chelydra.org/turtle_prehistory.html

Enchanted Learning.com
http://www.enchantedlearning.com/subjects/animals/Animalbabies.shtml

McFarlan, D (Editor); McCarthy, M. (Editor); Young, M (Editor). (1991).
The Guinness Book of Records 1992. Facts on File, New York, NY, U.S.A.

NEFSC Fish FAQ
http://www.nefsc.noaa.gov/faq/fishfaq11.html

Ocean Life – Interview with turtle expert Richard Reina
http://teacher.scholastic.com/activities/explorer/oceanlife/main.asp?article=interview_reina&template=meet_explorer

Seaturtle.org
http://www.seaturtle.org/glossary/index.shtml?

Seaturtle.org
http://www.seaturtle.org/tracking/faq.shtml

Seaworld.org. Sea Turtles
http://www.seaworld.org/infobooks/SeaTurtle/stsenses.html

Spotila, J.R. (2004). Sea Turtles: A Complete Guide to Their Biology, Behavior, and Conservation. The John Hopkins University Press, Baltimore, USA.

Kids’ Question About Turtles
http://www.turtlepuddle.org/kidspage/questions.html

http://www.sandiegozoo.org/animalbytes/t-turtle.html