Turtle

In this episode of the I Can't Sleep Podcast, fall asleep learning about turtles. Yes, they are cute and seem friendly. But don't let that fool you. Just think about how slow they are and the fact that you're going to learn a lot of useless information about them. You're going to love this one. Happy sleeping!

Transcript

Welcome to the I Can't Sleep podcast,

Where I read random articles from across the web to bore you to sleep with my soothing voice.

I'm your host,

Benjamin Boster.

Today's episode is from a Wikipedia article titled,

Turtle.

Turtles are an order of reptiles known as testidons,

Characterized by a special shell developed mainly from their ribs.

Modern turtles are divided into two major groups,

The pleurodera,

Side-necked turtles,

And cryptodera,

Hidden-neck turtles,

Which differ in the way the head retracts.

There are 360 living and recently extinct species of turtles,

Including land-dwelling tortoises and freshwater terrapins.

They are found on most continents,

Some islands,

And in the case of sea turtles,

Much of the ocean.

Like other amniotes,

Reptiles,

Birds,

And mammals,

They breathe air and do not lay eggs underwater,

Although many species live in or around water.

Turtle shells are made mostly of bone.

The upper part is the domed carapace,

While the underside is the flatter plastron or belly plate.

Its outer surface is covered in scales made of keratin,

The material of hair,

Horns,

And claws.

The carapace bones develop from ribs that grow sideways and develop into broad,

Flat plates that join up to cover the body.

Turtles are ectotherms,

Or cold-blooded,

Meaning that their internal temperature varies with their direct environment.

They are generally opportunistic omnivores and mainly feed on plants and animals with limited movements.

Many turtles migrate short distances seasonally.

Sea turtles are the only reptiles that migrate long distances to lay their eggs on a favored beach.

Turtles have appeared in myths and folktales around the world.

Some terrestrial and freshwater species are widely kept as pets.

Turtles have been hunted for their meat,

For use in traditional medicine,

And for their shells.

Sea turtles are often killed accidentally as bycatch in fishing nets.

Turtle habitats around the world are being destroyed.

As a result of these pressures,

Many species are extinct or threatened with extinction.

The word turtle is borrowed from the French word torte,

Or torte,

Turtle,

Tortoise.

It is a common name and may be used without knowledge of taxonomic distinctions.

In North America,

It may denote the order as a whole.

In Britain,

The name is used for sea turtles as opposed to freshwater terrapins and land-dwelling tortoises.

In Australia,

Which lacks true tortoises,

Non-marine turtles were traditionally called tortoises.

But more recently,

Turtle has been used for the entire group.

The name of the order,

Testudines,

Is based on the Latin word testudo,

Tortoise,

And was coined by German naturalist August Batch in 1788.

The order has also been historically known as Keloni and Kelonia,

Which are based on the ancient Greek word Kelone,

Tortoise.

Testudines is the official order name due to the principle of priority.

The term Kelonian is used as a formal name for members of the group.

The largest living species of turtle and fourth largest reptile is the leatherback turtle,

Which can reach over 2.

7 meters in length and weigh over 500 kilograms.

The largest known turtle was Archelon ischeros,

A late Cretaceous sea turtle,

Up to 4.

5 meters long,

5.

25 meters wide between the tips of the front flippers,

And estimated to have weighed over 2,

200 kilograms.

The smallest living turtle is Corsobia signatus of South Africa,

Measuring no more than 10 centimeters in length and weighing 172 grams.

The shell of a turtle is unique among vertebrates and serves to protect the animal and provide shelter from the elements.

It is primarily made of 50 to 60 bones and consists of two parts,

The domed dorsal back carapace and the flatter ventral belly plastron.

They are connected by lateral side extensions of the plastron.

The carapace is fused with the vertebrae and ribs while the plastron is formed from bones of the shoulder girdle,

Sternum,

And gastrolia,

Abdominal ribs.

During development,

The ribs grow sideways into a carapacial ridge,

Unique to turtles,

Entering the dermis,

Inner skin of the back to support the carapace.

The development is signaled locally by proteins known as fibroblast growth factors that include FGF10.

The shoulder girdle in turtles is made up of two bones,

The scapula and the caricoid.

Both the shoulder and pelvic girdles of turtles are located within the shell and hence are effectively within the rib cage.

The trunk ribs grow over the shoulder girdle during development.

The shell is covered in epidermal outer skin scales known as scutes that are made of keratin,

The same substance that makes up hair and fingernails.

Typically,

A turtle has 38 scutes in the carapace and 16 on the plastron,

Giving them 54 in total.

Carapace scutes are divided into marginals around the margin and vertebrals over the vertebral column,

Though the scute that overlays the neck is called the cervical.

Pleurals are present between the marginals and vertebrals.

Plastron scutes include gullars,

Throat,

Humerals,

Pectorals,

Abdominals,

And anals.

Side neck turtles additionally have intergular scutes between the gullars.

Turtle scutes are usually structured like mosaic tiles,

But some species like the hawksbill sea turtle have overlapping scutes on the carapace.

The shapes of turtle shells vary with the adaptations of the individual species and sometimes with sex.

Land-dwelling turtles are more dome-shaped,

Which appears to make them more resistant to being crushed by large animals.

Aquatic turtles have flatter,

Smoother shells that allow them to cut through the water.

Sea turtles in particular have streamlined shells that reduce the drag and increase stability in the open ocean.

Some turtle species have pointy or spiked shells that provide extra protection from predators and camouflage against leafy ground.

The lumps of a tortoise shell can tilt its body when it gets flipped over,

Allowing it to flip back.

In male tortoises,

The tip of the plastron is thickened and used for budding and ramming during combat.

Shells vary in flexibility.

Some species,

Such as box turtles,

Lack the lateral extensions and instead have the carapace bones fully fused or ankylosed together.

Several species have hinges on their shells,

Usually on the plastron,

Which allow them to expand and contract.

Soft-shelled turtles have rubbery edges due to the loss of bones.

The leatherback turtle has hardly any bones in its shell,

But has thick connective tissue and an outer layer of leathery skin.

The turtle's skull is unique among living amniotes,

Which includes reptiles,

Birds,

And mammals.

It is solid and rigid with no openings for muscle attachment.

Muscles instead attach to recesses in the back of the skull.

Turtle skulls vary in shape from the long and narrow skulls of soft shells to the broad and flattened skull of the mata mata.

Some turtle species have developed large and thick heads,

Allowing for greater muscle mass and stronger bites.

Turtles that are carnivorous or dorophagous,

Eating hard-shelled animals,

Have the most powerful bites.

For example,

The dorophagous Mesoclemus nasuta has a bite force of 432 pounds of force.

Species that are insectivores,

Peshivores,

Fish-eating,

Or omnivores have lower bite forces.

Living turtles lack teeth,

But have beaks made of keratin sheaths along the edges of the jaws.

These sheaths may have sharp edges for cutting meat,

Serrations for clipping plants,

Or broad plates for breaking mollusks.

The necks of turtles are highly flexible,

Possibly to compensate for the rigid shells.

Some species like sea turtles have short necks,

While others such as snake-necked turtles have long ones.

Despite this,

All turtle species have eight-neck vertebrae,

A consistency not found in other reptiles,

But similar to mammals.

Some snake-necked turtles have both long necks and large heads,

Limiting their ability to lift them when not in water.

Some turtles have folded structures in the larynx or glottis that vibrate to produce sound.

Other species have elastin-rich vocal cords.

Due to their heavy shells,

Turtles are slow-moving on land.

A desert tortoise moves at only 0.

22 to 0.

48 kilometers per hour.

By contrast,

Sea turtles can swim at 30 kilometers per hour.

The limbs of turtles are adapted for various means of locomotion and habits,

And most have five toes.

Tortoises are specialized for terrestrial environments and have column-like legs with elephant-like feet and short toes.

The gopher tortoise has flattened front limbs for digging in the substrate.

Freshwater turtles have more flexible legs and longer toes with webbing,

Giving them thrust in the water.

Some of these species,

Such as snapping turtles and mud turtles,

Mainly walk along the water bottom as they would on land.

Others,

Such as terrapins,

Swim by paddling with all four limbs,

Switching between the opposing front and hind limbs,

Which keeps their direction stable.

Sea turtles and the pick-nosed turtle are the most specialized for swimming.

Their front limbs have evolved into flippers,

While the shorter hind limbs are shaped more like rudders.

The front limbs provide most of the thrust for swimming,

While the hind limbs serve as stabilizer.

Sea turtles,

Such as the green sea turtle,

Rotate the front limb flippers like a bird's wings to generate a propulsive force on both the upstroke and on the downstroke.

This in contrast to similar-sized freshwater turtles,

Measurements having been made on young animals in each case,

Such as the Caspian turtle,

Which uses the front limbs like the oars of a rowing boat,

Creating substantial negative thrust on the recovery stroke in each cycle.

In addition,

The streamlining of the marine turtles reduces drag.

As a result,

Marine turtles produce a propulsive force twice as large and swim six times as fast as freshwater turtles.

The swimming efficiency of young marine turtles is similar to that of fast-swimming fish of open water,

Like mackerel.

Compared to other reptiles,

Turtles tend to have reduced tails,

But these vary in both length and thickness among species in between sexes.

Snapping turtles and the big-headed turtle have longer tails.

The latter uses it for balance while climbing.

Turtles make use of vision to find food and mates,

Avoid predators,

And orient themselves.

The retina's light-sensitive cells include both rods for vision and low light,

And cones with three different photo pigments for bright light,

Where they have full color vision.

There is possibly a fourth type of cone that detects ultraviolet,

As hatchling sea turtles respond experimentally to ultraviolet light,

But it is unknown if they can distinguish this from longer wavelengths.

A freshwater turtle,

The red-eared slider,

Has an exceptional seven types of cone cell.

Sea turtles orient themselves on land by night using visual features detected in dim light.

They can use their eyes in clear surface water,

Muddy coasts,

The darkness of the deep ocean,

And also above water.

Unlike in terrestrial turtles,

The cornea,

The curved surface that lets light into the eye,

Does not help to focus light on the retina,

So focusing underwater is handled entirely by the retina.

Underwater is handled entirely by the lens behind the cornea.

The cone cells contain oil droplets placed to shift perception toward the red part of the spectrum,

Improving color discrimination.

Visual acuity,

Studied in hatchlings,

Is highest in a horizontal band with the retinal cells packed about twice as densely as elsewhere.

This gives the best vision along the visual horizon.

Sea turtles do not appear to use polarized light for orientation,

As many other animals do.

The deep diving leatherback turtle lacks specific adaptations to low light,

Such as large eyes,

Large lenses,

Or a reflective tapetum.

It may rely on seeing the bioluminescence of prey when hunting in deep water.

Turtles have no ear openings.

The eardrum is covered with scales and encircled by a bony aortic capsule,

Which is absent in other reptiles.

Their hearing thresholds are high in comparison to other reptiles,

Reaching up to 500 hertz in air,

But underwater they are more attuned to lower frequencies.

The loggerhead sea turtle has been shown experimentally to respond to low sounds,

With maximal sensitivity between 100 and 400 hertz.

Turtles have olfactory smell and vomeronasal receptors along the nasal cavity,

The latter of which are used to detect chemical signals.

Experiments on green sea turtles showed they could learn to respond to a selection of different odorants chemicals,

Such as triethylamine and cinnamaldehyde,

Which were detected by olfaction in the nose.

Such signals could be used in navigation.

The rigid shell of turtles is not capable of expanding and making room for the lungs as in other amniotes,

So they have had to evolve special adaptations for respiration.

The lungs of turtles are attached directly to the carapace above,

While below connective tissue attaches them to the organs.

They have multiple lateral,

Side,

And medial middle chambers,

The numbers of which vary between species and one terminal end chamber.

The lungs are ventilated using specific groups of abdominal muscles attached to the organs that pull and push on them.

Specifically,

It is the turtle's large liver that compresses the lungs.

Under the lungs in the colomic cavity,

The liver is connected to the right lung by the root,

And the stomach is directly attached to the left lung and to the liver by a mesentery.

When the liver is pulled down,

Inhalation begins.

Supporting the lungs is a wall or septum,

Which is thought to prevent them from collapsing.

During exhalation,

The contraction of the transversus abdominis muscle propels the organs into the lungs and expels air.

Conversely,

During inhalation,

The relaxing and flattening of the oblique abdominis muscles pulls the transversus back down,

Allowing air back into the lungs.

Although many turtles spend large amounts of their lives underwater,

All turtles breathe air and must surface at regular intervals to refill their lungs.

Depending on the species,

Immersion periods vary between a minute and an hour.

Turtles share the linked circulatory and pulmonary systems of vertebrates,

Where the three-chambered heart pumps deoxygenated blood through the lungs and then pumps the returned oxygenated blood through the body's tissues.

The cardiopulmonary system is both structural and physiological adaptations that distinguish it from other vertebrates.

Turtles have a large lung volume and can move blood through non-pulmonary blood vessels,

Including some within the heart to avoid the lungs while they are not breathing.

They can hold their breath for much longer periods than other reptiles,

And they can tolerate the resulting low oxygen levels.

They can moderate the increase in acidity during anaerobic,

Non-oxygen-based respiration by chemical buffering,

And they can lie dormant for months in estivation or brumation.

The heart has two atria,

But only one ventricle.

The ventricle is subdivided into three chambers.

A muscular ridge enables a complex pattern of blood flow so that the blood can be directed either to the lungs via the pulmonary artery or to the body via the aorta.

The ability to separate the two outflows varies between species.

The leatherback has a powerful muscular ridge enabling almost complete separation of the outflows,

Supporting its actively swimming lifestyle.

The ridge is less well-developed in freshwater turtles like the sliders.

Turtles are capable of enduring periods of anaerobic respiration longer than many other vertebrates.

This process breaks down sugars incompletely to lactic acid,

Rather than all the way to carbon dioxide and water,

As in aerobic,

Oxygen-based respiration.

They make use of the shell as a source of additional buffering agents for combating increased acidity and as a sink for lactic acid.

Turtles,

Like other reptiles,

Have a limited ability to regulate their body temperature.

This ability varies between species and with body size.

Small pond turtles regulate their temperature by crawling out of the water and basking in the sun,

While small terrestrial turtles move between sunny and shady places to adjust their temperature.

Large species,

Both terrestrial and marine,

Have sufficient mass to give them substantial thermal inertia,

Meaning that they heat up or cool down over many hours.

The Aldabra giant tortoise weighs up to some 60 kilograms and is able to allow its temperature to rise to some 33 degrees Celsius on a hot day and to fall naturally to around 29 degrees Celsius by night.

Some giant tortoises seek out shade to avoid overheating on sunny days.

On Grand Terra Island,

Food is scarce inland,

Shade is scarce near the coast,

And the tortoises compete for space under the few trees on hot days.

Large males may push smaller females out of the shade and some then overheat and die.

Adult sea turtles,

Too,

Have large enough bodies that they can,

To some extent,

Control their temperature.

The largest turtle,

The leatherback,

Can swim in the waters off Nova Scotia,

Which may be as cold as eight degrees Celsius,

While their body temperature has been measured at up to 12 degrees Celsius warmer than the surrounding water.

To help keep their temperature up,

They have a system of counter-current heat exchange in the blood vessels between their body core and the skin of their flippers.

The vessels supplying the head are insulated by fat around the neck.

Most turtle species are opportunistic omnivores.

Land-dwelling species are more herbivorous and aquatic ones more carnivorous.

Generally lacking speed and agility,

Most turtles feed either on plant material or on animals with limited movements,

Like mollusks,

Worms,

And insect larvae.

Some species,

Such as the African helmeted turtle and snapping turtles,

Eat fish,

Amphibians,

Reptiles,

Including other turtles,

Birds,

And mammals.

They may take them by ambush,

But also scavenge.

The alligator snapping turtle has a worm-like appendage on its tongue that it uses to lure fish into its mouth.

Tortoises are the most herbivorous group,

Consuming grasses,

Leaves,

And fruits.

Many turtle species,

Including tortoises,

Supplement their diet with eggshells,

Animal bones,

Hair,

And droppings for extra nutrients.

Turtles generally eat their food in a straightforward way,

Though some species have special feeding techniques.

The yellow-spotted river turtle and the painted turtle may filter feed by skimming the water surface with their mouth and throat open to collect particles of food.

When the mouth closes,

The throat constricts and water is pushed out through the nostrils in the gap in between the jaws.

Some species employ a gape-and-suck method,

Where the turtle opens its jaws and expands its throat widely,

Sucking the prey in.

The diet of an individual within a species may change with age,

Sex,

And season,

And may also differ between populations.

In many species,

Juveniles are generally carnivorous,

But become more herbivorous as adults.

With barber's map turtle,

The larger female mainly eats mollusks,

While the male usually eats arthropods.

Blanding's turtle may feed mainly on snails or crayfish,

Depending on the population.

The European pond turtle has been recorded as being mostly carnivorous much of the year,

But switching to water lilies during the summer.

Some species have developed specialized diets,

Such as the hawksbill,

Which eats sponges,

The leatherback,

Which feeds on jellyfish,

And the Mekong snail-eating turtle.

While popularly thought of as mute,

Turtles make various sounds to communicate.

One study which recorded 53 species found that all of them vocalized.

Tortoises may bellow when courting and mating.

Various species of both freshwater and sea turtles emit short,

Low-frequency calls from the time they are in the egg to when they are adults.

These vocalizations may serve to create group cohesion when migrating.

The oblong turtle has a particularly large vocal range,

Producing sounds described as clacks,

Clicks,

Squawks,

Hoots,

Various kinds of chirps,

Wails,

Hoos,

Grunts,

Growls,

Blowbursts,

Howls,

And drum rolls.

Play behavior has been documented in some turtle species.

In the laboratory,

Florida red-bellied cooters can learn novel tasks and have demonstrated a long-term memory of at least 7.

5 months.

Similarly,

Giant tortoises can learn and remember tasks,

And master lessons much faster when trained in groups.

Tortoises appear to be able to retain operant conditioning nine years after their initial training.

Studies have shown that turtles can navigate the environment using landmarks and a map-like system,

Resulting in accurate direct routes towards a goal.

Navigation in turtles has been correlated to high cognition function in the medial cortex region of the brain.

When sensing danger,

A turtle may flee,

Freeze,

Or withdraw into its shell.

Freshwater turtles flee into the water,

Though the Sonora mud turtle may take refuge on land as the shallow temporary ponds they inhabit make them vulnerable.

When startled,

A soft-shelled turtle may dive underwater and bury itself under the seafloor.

Several species produce foul-smelling chemicals from musk glands.

Other tactics include threat displays,

And Bell's hinged-back tortoise can play dead.

When attacked,

Big-headed turtle hatchlings squeal,

Possibly startling the predator.

Turtles are the only reptiles that migrate long distances,

More specifically the marine species that can travel up to thousands of kilometers.

Some non-marine turtles migrate seasonally over much shorter distances,

Up to around 27 kilometers to lay eggs.

Such short migrations are comparable to those of some lizards,

Snakes,

And crocodilians.

Sea turtles nest in a separate area,

Such as a beach,

Leaving the eggs to hatch unattended.

The young turtles leave that area,

Migrating long distances in the years or decades in which they grow to maturity,

And then return seemingly to the same area every few years to mate and lay eggs,

Though the precision varies between species and populations.

This natal homing has appeared remarkable to biologists,

Though there is now plentiful evidence for it,

Including from genetics.

How sea turtles navigate to their breeding beaches remains unknown.

One possibility is imprinting,

As in salmon,

Where the young learn the chemical signature effectively the scent,

Or their home waters,

Before leaving,

And remember that when the time comes for them to return as adults.

Another possible cue is the orientation of the Earth's magnetic field at the natal beach.

There is experimental evidence that turtles have an effective magnetic sense,

And that they use this in navigation.

Proof that homing occurs is derived from genetic analysis of populations of loggerheads,

Hawksbills,

Leatherbacks,

And olive ridleys by nesting place.

For each of these species,

The populations in different places have their own mitochondrial DNA genetic signatures that persist over the years.

This shows that the populations are distinct,

And that homing must be occurring reliably.

Turtles,

Including sea turtles,

Lay their eggs on land,

Although some lay eggs near water that rises and falls in levels,

Submerging the eggs.

While most species build nests and lay eggs where they forage,

Some travel miles.

The common snapping turtle walks five kilometers on land,

While sea turtles travel even further.

The leatherbacks swim some 12,

000 kilometers to its nesting beaches.

Most turtles create a nest for their eggs.

Females usually dig a flask-like chamber in the substrate.

Other species lay their eggs in vegetation or crevices.

Females choose nesting locations based on environmental factors,

Such as temperature and humidity,

Which are important for developing embryos.

Depending on the species,

The number of eggs laid varies from one to over 100.

Larger females can lay eggs that are greater in number or bigger in size.

Compared to freshwater turtles,

Tortoises deposit fewer but larger eggs.

Females can lay multiple clutches throughout a season,

Particularly in species that experience unpredictable monsoons.

Most mother turtles do no more in the way of parental care than covering their eggs and immediately leaving,

Though some species guard their nests for days or weeks.

Eggs vary between rounded,

Oval,

Elongated,

And between hard and soft-shelled.

Some species have their sex determined by temperature.

In some species,

Higher temperatures produce females and lower ones produce males,

While in others,

Milder temperatures produce males and both hot and cold extremes produce females.

In other species,

Sex is determined genetically.

The length of incubation for turtle eggs varies from two to three months for temperate species and four months to over a year for tropical species.

Species that live in warm,

Temperate climates can delay their development.

Hatching young turtles break out of the shell using an egg tooth,

A sharp projection that exists temporarily on their upper beak.

Hatchlings dig themselves out of the nest and find safety in vegetation or water.

Some species stay in the nest for longer,

Be it for overwintering or to wait for the rain to loosen the soil for them to dig out.

Young turtles are highly vulnerable to predators,

Both in the egg and as hatchlings.

Mortality is high during this period,

But significantly decreases when they reach adulthood.

Most species grow quickly during their early years and slow down when they are mature.

Turtles can live long lives.

The oldest living turtle and land animal is said to be a giant tortoise named Jonathan,

Who turned 187 in 2019.

A Galapagos tortoise named Harriet was collected by Charles Darwin in 1835.

It died in 2006,

Having lived for at least 176 years.

Most wild turtles do not reach that age.

Turtles keep growing new scutes under the previous scutes every year,

Allowing researchers to estimate how long they have lived.

They also age slowly.

The survival rate for adult turtles can reach 99% per year.

The turtles' exact ancestry has been disputed.

It was believed they were the only surviving branch of the ancient evolutionary grade Anapsida,

Which includes groups such as Procolophonids and Periosaurs.

All Anapsid skulls lack a temporal opening,

While all other living amniotes have temporal openings.

It was later suggested that the Anapsid-like turtle skulls may be due to backward evolution rather than to Anapsid descent.

Fossil evidence has shown that early stem turtles possessed small temporal openings.

Turtles are widely distributed across the world's continents,

Oceans,

And islands with terrestrial,

Fully aquatic,

And semi-aquatic species.

Sea turtles are mainly tropical and subtropical,

But leatherbacks can be found in colder areas of the Atlantic and Pacific.

Living Pleurodera all live in freshwater and are found only in the Southern Hemisphere.

The Cryptodera include terrestrial,

Freshwater,

And marine species,

And these range more widely.

The world region's richest in non-marine turtle species are the Amazon Basin,

The Gulf of Mexico drainages of the United States,

And parts of South and Southeast Asia.

For turtles in colder climates,

Their distribution is limited by constraints on reproduction,

Which is reduced by long hibernations.

North American species barely range above the Southern Canadian border.

Some turtles are found at high altitudes,

For example.

The species Terrapinae ornata occurs up to 2,

000 meters in New Mexico.

Conversely,

The leatherback sea turtle can dive over 1,

200 meters.

Species of the genus Gophros can tolerate both below freezing and over 40 degrees Celsius in body temperature,

Though they are most active at 26 to 34 degrees Celsius.

Among vertebrate orders,

Turtles are second only to primates in the percentage of threatened species.

360 modern species have existed since 1500 AD.

Of these,

51 to 55% are considered threatened,

And 60% considered threatened or extinct.

Turtles face many threats,

Including habitat destruction,

Harvesting for consumption,

The pet trade,

Light pollution,

And climate change.

Asian species have a particularly high extinction risk,

Primarily due to their long-term unsustainable exploitation for food and medicine.

And about 83% of Asia's non-marine turtle species are considered threatened.

As of 2021,

Turtle extinction is progressing much faster than during the Cretaceous-Tertiary extinction.

At this rate,

All turtles could be extinct in a few centuries.

Turtle hatcheries can be set up when protection against flooding,

Erosion,

Predation,

Or heavy poaching is required.

Chinese markets have sought to satisfy an increasing demand for turtle meat with farm turtles.

In 2007,

It was estimated that over 1,

000 turtle farms operated in China.

All the same,

Wild turtles continue to be caught and sent to market in large numbers,

Resulting in what conservationists have called the Asian turtle crisis.

In the words of the biologist George Amato,

The hunting of turtles vacuumed up entire species from areas in Southeast Asia,

Even as biologists still did not know how many species lived in the region.

In 2000,

All the Asian box turtles were placed in the CITES list of endangered species.

Harvesting wild turtles is legal in some American states,

And there has been a growing demand for American turtles in China.

The Florida Fish and Wildlife Conservation Commission estimated in 2008 that around 3,

000 pounds of soft-shelled turtles were exported weekly via Tampa International Airport.

However,

The great majority of turtles exported from the US between 2002 and 2005 were farmed.

Large numbers of sea turtles are accidentally killed in long lines,

Gill nets,

And trawling nets as bycatch.

A 2010 study suggested that over eight million had been killed between 1990 and 2008.

The Eastern Pacific and the Mediterranean were identified as among the areas worst affected.

Since the 1980s,

The United States has required all shrimp trawlers to fit their nets with turtle excluder devices to prevent turtles from being entangled in the net and drowning.

More locally,

Other human activities are affecting marine turtles.

In Australia,

Queensland's shark culling program,

Which uses shark nets and drum lines,

Has killed over 5,

000 turtles as bycatch between 1962 and 2015,

Including 719 loggerhead turtles and 33 hawksbill sea turtles,

Which are listed as critically endangered.

Native turtle populations can also be threatened by invasive ones.

The Central North American red-eared slider turtle has been listed among the world's worst invasive species pet turtle having been released globally.

They appear to compete with native turtle species in Eastern and Western North America,

Europe,

And Japan.

Turtles have featured in human cultures across the world since ancient times.

They are generally viewed positively despite not being cuddly or flashy.

Their association with the ancient times and old age have contributed to their endearing image.

In Hindu mythology,

The world turtle,

Named Kurma or Kachkappa,

Supports four elephants on his back.

They in turn carry the weight of the whole world on their backs.

The turtle is one of 10 avatars or incarnations of the god Vishnu.

The yoga pose,

Kurmasana,

Is named for the avatar.

World turtles are found in Native American cultures including the Algonquin,

Iroquois,

And Lenape.

They tell many versions of the creation story of Turtle Island.

One version has muskrat pile up earth on turtle's back creating the continent of North America.

An Iroquois version has the pregnant sky woman fall through a hole in the sky between a tree's roots or she is caught by birds who land her safely on turtle's back.

The earth grows around her.

The turtle here is altruistic,

But the world is a heavy burden and the turtle sometimes shakes itself to relieve the load causing earthquakes.

Reviews

We had red eared sliders growing up and I still fell right back to sleep 😴 Thank you 😊

Your voice lulls me into a peaceful sleep every time and the bonus is, I end up learning a few things before I fall asleep. Win-win! Thank you.

"Turtle girdle" is my new favorite term. Thank you for this.

Did what it was supposed to do! 💤 Thank you! 🐢 🙏🏼