type of animal is a sea turtle?
A reptile. Reptiles are cold-blooded animals, which have existed
since Pre-historic times.
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.
many species of sea turtle exist?
There are eight extant species:-
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)
long have sea turtles existed for?
230 million years. Present day species have evolved
from those living in Prehistoric times.
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.
are the differences between turtles, tortoises and terrapins?
tortoises are turtles, but not all turtles are tortoises.
All terrapins are turtles, but not all turtles are terrapins.
Some turtles are just turtles.”
World of Turtles and Crocodiles
- 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).
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.
– 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
– 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
big was the largest sea turtle ever recorded?
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
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.
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.
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.
can sea turtles be aged?
deep can sea turtles dive?
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.
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.
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.
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.
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
How long can a sea turtle hold its breath? And why
do they drown?
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.
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.
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.
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.
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.
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
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.
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.
fast do they swim?
Sea turtles have been recorded swimming at speeds of 30mph
(in bursts), but generally they swim at around 4 – 5mph.
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.
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.
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.
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.
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.”
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.
sea turtles have any kind of relationship with other marine
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
are solitary animals and when in captivity they will fight
(bite) each other.
is a Male/ Female turtle called?
There is no name given to a male or female turtle. They are
just referred to as turtles.
is a baby turtle called?
Baby turtles are called “hatchlings” because they
have recently “hatched” out of their eggshells.
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”.
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.
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.
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
is a turtle's shell made of?
Individual bones covered with Keratin form the shell of a
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.
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’.
can I find more information about sea turtles?
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).
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.
sea turtles live in fresh water and salt water?
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
is most common in the Mediterranean?
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!
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.
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
with other species
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
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.
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?
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.
are the white organisms attached to sea turtles and their
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.
species interact with loggerhead sea turtles?
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.
No. Turtles mate with numerous turtles during the course
of a breeding season.
do sea turtles return to the vicinity of their natal beach
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
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).
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
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.
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
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.
determines the sex of a sea turtle?
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
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.
species nest in the Mediterranean?
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
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 -
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.
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
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.
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.
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
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.
is the importance of sea turtles? Why try to conserve them?
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.
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.
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.
of the seven types of sea turtles in the world, unfortunately
six of these are on the redlist as either endangered or critically
to the IUCN Red List
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/
any species of turtles become extinct?
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.
global warming affect turtles?
global warming will have a significant impact on the resilience
and sustainability of sea turtle populations.
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.
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.
a few Aquariums, Zoo’s and Rescue/ Rehabilitation Centres
are permitted to maintain sea turtles for their care and public
British Chelonia Group: http://www.britishcheloniagroup.org.uk/
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@example.com
a Turkish NGO has pioneered volunteering on sea turtle nesting
beaches in Turkey so visit: www.ekad.org
and contact: firstname.lastname@example.org.
Google will bring up an array of such projects if you search
on the Internet.
would like to gain experience working with turtles. How can
I work with turtles?
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?
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.
do my donations help turtles?
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.
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,
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.
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:
I’m interested in gaining experience doing field
research. Can I volunteer to help with the turtle fieldwork?
there are many field research on sea turtles being carried
out around the world some good places to start include the
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.
an excellent online resource check out
page has sea turtle programs in Cuba, Brazil, Australia,
Ecuador and anywhere these majestic creatures roam.
(Turtle Pre history)
D (Editor); McCarthy, M. (Editor); Young, M (Editor). (1991).
The Guinness Book of Records 1992. Facts on File, New York,
NEFSC Fish FAQ
Life – Interview with turtle expert Richard Reina
J.R. (2004). Sea Turtles: A Complete Guide to Their Biology,
Behavior, and Conservation. The John Hopkins University Press,
Question About Turtles