Animalium

Title: Animalium
Author(s): Jenny Broom, Katie Scott
Release year: 2014
Publisher: Big Picture Press

Why in Database: A very large format book with a variety of animals. Two pages are dedicated to turtles, one has a picture of various turtles, the other has a general description of the turtles and specific information about the turtles shown. In addition, turtles in the form of drawings appear in many other places in the book, on the pages between chapters or on the inside pages of the covers.

Turtles, Tortoises and Terrapins
Turtles are members of an order of reptiles called Testudines, which also includes tortoises and aquatic terrapins. This name refers to the hard shell that all its species possess, as a testudo in ancient Rome was a hard screen or shield that soldiers used to protect themselves. Little of the modern turtle’s anatomy has changed from its prehistoric ancestors’, who date back more than 220 million years, making turtles and tortoises more ancient than all snakes, lizards and crocodiles.
Turtles’ shells are attached to their bodies, and so their protective armour can never be taken off or left behind. Land-dwelling tortoises have higher, domed shells, whilst aquatic species have flatter shells. To hide inside their shells, some species fold their head alongside their shoulder, whilst others retract their neck and head backwards. Box turtles have a hinged bony plate that allows their shells to close completely.
Males will often perform elaborate courtship rituals to impress females, who lay shelled eggs after mating. The temperature that the eggs are kept at affects the sex of the hatchlings (a trait shared with crocodiles and some lizards).

Key to plate
1: Green sea turtle
Chelonia mydas
Length: 150 centimetres
This large sea turtle is a herbivore, feeding mostly on seagrasses. Populations of green sea turtles can be found in tropical waters of the Atlantic and Pacific oceans.
2: Painted turtle
Chtysemys pitta bellii
Length: 25 centimetres
Also known as the firebelly turtle. this species spends long hours basking in the sun, particularly early in the day. It is common sight to find several painted turtles piled on top of one another on a log.
ifey to plate
3: Blanding’s turtle
Emycloidea blandingii
Length: 20 centimetres
This turtle has a plastral hinge that forms a protective hatch at the front of its shell. It is omnivorous, feeding on a range of foods such as berries, fish and frogs.
4: Diamondback terrapin
Malaclemys terrapin
Length: 15 centimetres
The mild-mannered diamondback terrapin lives in brackish lagoons, tidal marshlands and sandy beaches in east-coast America. The species nearly became extinct due to over-hunting and destruction of its habitat
5: Leopard tortoise
Geoche/one pordoirs
Length: St centimetres
The leopard tortoise is a large tortoise found in savannah habitats in Africa, where it can live for up to 100 years. Its grasping toenails make A an agile walker, strong swimmer and surprisingly good climber.
6: Indian star tortoise
Geochelone elegans Length: 28 centimetres
The Indian star tortoise has a high tolerance of water, and so can be found in places that experience monsoon seasons. Its dome shape allows it to easily self-right.

Author: XYuriTT

Incedible Journeys Amazing Animal Migrations

Title: Incedible Journeys Amazing Animal Migrations
Author(s): Dwight Holing
Release year: 2011
Publisher: Weeldon Owen

Why in Database: Book about animals migration. The turtles first appear in a series of minor mentions, and then there are two whole pages devoted to them, with a lot of passages on those two pages. There are also pictures here and there.

Incredible Journeys is filled with such stories. Meet a bird that flies from pole to pole and back again – a yearly trip of nearly 80,000 kilometres. Follow a sea turtle hatchling, so small it would fit in your hand, as it cracks out of its egg, scrambles across a beach and catches a current that carries it across the ocean.

Conveyor belt
Turtles use Atlantic Ocean currents to carry them smoothly between far-flung feeding and nesting sites.

Jellyfish, eels and sea turtles undertake incredible journeys, too.

Ocean currents sucha s the Gulf Stream give travellers like sea turtles a lift on long migrations.

Long Lives
Sea turtles live for up to 50 years and migrate across the world’s great oceans.

All of the following fragments are from the two mentioned turtle-filled pages:

Leatherback turtle fact file
Type Sea turtle
Family Dermochelyidae
Scientific name Dermochelys coriacea
Diet Jellyfish
Average lifespan 45 years
Size Up to 2m
Weight Up to 700kg

Race winners Large flippers and a streamlined body make leatherbacks the fastest swimming sea turtle.

Riding the current
Among the oldest of all creatures, sea turtles evolved over 110 million years ago. Seven species still exist, but all are at risk of extinction. Fishing and building on beaches are part of the reason why. Sea turtles spend nearly all of their time in the water, coming ashore only briefly to lay their eggs. Catching ocean currents helps them when migrating. Some species, like the leatherback, travel across entire oceans.

Leatherback
Leatherbacks are the largest of all sea turtles and are unlike most others. Their shell is not bony but instead, is made of skin and oily flesh. Their flippers are the biggest in proportion to their overall size. The front pair can grow as long as 2.7 metres. Leatherbacks have the widest global distribution, too. They range from Norway to the tip of New Zealand. They are also the deepest divers, able to go 1,280 metres below the surface.

Cold waters An extra layer of fat helps leatherbacks keep from freezing in cold water like that of Alaska

Migration
Leatherbacks travel from cold water, where they feed, to warm-climate beaches, where they hatch. Journeys average 6,000 kilometres. One sea turtle was tracked from its nesting site in Indonesia to California – a 20,000-kilometre trip.

Global Leatherbacks roam the oceans widely, including to the waters off the Cape of Good Hope, South Africa (right).

Nesting and laying
Most sea turtle species return to lay their eggs on the same beach where they hatched years before. The female crawls to a dry part of the beach after mating and uses her front flippers to dig a shallow pit the size of her body. Then she shovels out an egg cavity using her cupped rear flippers and lays 80-120 eggs. She covers the eggs with sand when she has finished and heads back to the sea.

Hatchlings
It takes a little over a month for the eggs to hatch. The temperature beneath the sand determines which sex the hatchlings will be Temperatures warmer than 29.5°C produce females. Cooler temperatures produce males. Once the baby sea turtles break out of their shells, they waste no time heading for the safety of the water.

Sand tracks Gently sloping beaches make getting in and out of the water easier.

Darkness Turtles nest at night to help hide the eggs from predators like gulls.

Hatchlings
It takes a little over a month for the eggs to hatch. The temperature beneath the sand determines which sex the hatchlings will be. Temperatures warmer than 29.5°C produce females. Cooler temperatures produce males. Once the baby sea turtles break out of their shells, they waste no time heading for the safety of the water.

Mad dash Hatchlings must cross the beach quickly to avoid predators.

Author: XYuriTT

Africa: Eye to Eye with the Unknown

Title: Africa: Eye to Eye with the Unknown
Author(s): Michael Bright
Release year: 2013
Publisher: Quercus

Why in Database: Book related to the nature series with the same title. There are a lot of turtle fragments in it, one very long and a few small ones. Plus some graphics that we also show.

The first three pieces are minor references:

An isolated population of Nile softshell turtle shares Turkana’s waters with the crocodiles.

The presence of the turtles however, indicates that at some stage in the past, when rainfall in the area was far greater that it is today, Turkana was connected to the Nile river system.

The turtles hang out on the shores of a large island, known as Central Island, also a favoured nesting site for crocodiles.

The next piece is the longest:

EPIC RACE FOR LIFE

First a dusty head and then a pair of disproportionately large flippers push up through the sand: a turtle hatchling, no more than 7 cm (3 inches) across and a dirty grey colour, appears on the surface of the dune. Its limbs flail about wildly as it stretches and strains every tiny muscle in trying to free itself from the clinging sand. It had been incubating for two months underground, before breaking out of its leathery egg case and digging its way upwards, the danger of being buried alive never far away. It and its nest mates over a hundred of them – waited patiently just below the surface for the right moment to make the final push.

A sudden drop in temperature at sunset was the trigger. Now, in the twilight, the baby turtle finally emerges, but the pit from which it has tried to escape collapses, It’s near disaster. The turtle tumbles back down, but it’s still on top of the heap, so it scrambles over the tangle of heads and flippers of the other hatchlings and heaves itself onto the surface of the sand. The brightness of the sea in front and the darkness of the land behind the nest ensure that this tiny scrap of life heads in the right direction, but there are many obstacles blocking its route, and the youngster has the dubious distinction of being a handy bite-sized packet of protein, so there are many here taking a close interest in its first journey to the sea… in fact, its first journey anywhere.

Flotsam, washed up and dumped on the shore, becomes an insurmountable barrier, and even ripples in the sand slow down the hatchling’s dash across the beach. It must not stop, but keep on going. It has to reach the water’s edge in the shortest possible time. Its life depends on it. Its limbs are actually adapted for swimming but it’s exceptionally nimble over the sand. On dry, loose sand it moves forward by pushing against the solid wedge of sand particles that forms behind its flippers, and when it reaches the wet sand it advances by digging in with a claw on each flipper so it doesn’t slip.

All around it, other baby turtles are making the same headlong rush to the sea. They come from the many hundreds of nests dotted along the beach, but not all will make it. Pied crows swoop down and pick off any hatchlings tangled in tide-line debris, and ghost crabs intercept many of those that do get through, hauling them into their burrows in the sand before tearing them literally limb from limb. It will be a miracle if even a handful reach the ocean, for the first wave of hatchlings bears the brunt of attacks; but the sacrifice of a few hundred ensures that the following thousands have a better chance of making it to the sea.

The hatchling is a baby green sea turtle, born on the island of Mwali (Moheli) in the Comoros Archipelago. She’s a female, as are all her nest mates, their sex determined by the temperature of their nest. While the eggs were incubating, the temperature of the sand regularly rose above 29°C (84.2°F), so the entire clutch are females, Below 26°C (78.5 F) and they would have been males. It means that this little female hatchling will be out at sea until her twentieth birthday, when shell return to this same beach to deposit her first batch of eggs in the sand… that is, if she ever reaches the water’s edge. Only 30% make it this far, and the beach is only the first hazard. In the shallows there are more predators waiting and more obstacles to negotiate The hatchling swims powerfully, her head down and flippers pulling hard against the water. As she comes up for air she switches to doggy-paddling, raises her head above the surface for a quick breath, and then powers on through the surf, except that at 25 g (less than an ounce) the baby is turned over in the breaking waves and battered against the sand.
On reaching clear water beyond the surf line she surfaces for air again. It’s what the kites have been waiting for. They swoop down and scoop hatchlings from the surface, and even those hidden below are not safe. There are sharks offshore ready to intercept them on their way to deeper water. Even fewer will have made it this far, but the little female ploughs on towards the open sea, though her pace is gradually slowing, until it levels off after about twelve hours. All the while, she’s been swimming almost non-stop using the remnants of her yolk sac for energy; and she carries over ten times more yolk than she needs in her break for freedom so that she can keep going without feeding for up to fourteen days.
By that time, she’ll be swept along in the Mozambique Channel in a series of enormous anti-cyclonic eddies, each up to 300 km (186 miles) across. Where she and all the other survivors go for the next twenty years is a mystery (and only one in a thousand survives to adulthood), but wherever that might be will depend on the strength and direction of the ocean currents, especially those in the Mozambique Channel, birthplace as well of the formidable Agulhas Current.
The equatorial sun to the north powers the system, and it swirls inexorably southwards between Madagascar and the African mainland. Here, it strongly influences the climate of much of Mozambique, one factor that helps maintain an extraordinary and unexpected diversity of fauna and flora unsuRepublic of South Africassed in much of the rest of Africa.

The next three are captions to the photos appearing besides the above long fragment:

Breaking out of its leathery egg case and digging its way upwards, for a baby turtle the danger of being buried alive is never far away. All around it, other babies are making the same headlong rush to the sea… but not all will make it.

When they emerge from the sand, green sea turtle hatchlings head unerringly towards the sea, but all manner of dangers are waiting for them on the beach. Most make their run at night, when fewer predators are about, but the latecomers must run the gauntlet in daylight and as a consequence the casualty figures rise.

On reaching the water, the hatchling heads for the open sea, searching for upwellings where food is concentrated. It will live in the ocean for up to five years, feeding on zooplankton and small marine creatures, before heading for sea grass meadows along the shore where, while still an immature juvenile, it becomes a herbivore.

The next three fragments are again, smaller ones:

The water and all of floating life immersed in it (including, no doubt, a certain sea turtle hatchling growing a little every minute) is propelled southwestwards at about 6 knots (6.9 mph) to the Wild Coast of South Africa.

The dwarf ground sloths of the Caribbean island arc were next, about 6,000 years ago, followed by the giant crocodiles and giant land turtles of New Caledonia and nearby islands 3,000 years ago, the gorilla-size lemurs of Madagascar 2,000 years ago and New Zealand’s giant birds – moas and the giant Haast’s eagle – by AD 1400.

Together with assistant producer Rosie Thomas and production coordinator Hannah Smith, Hugh had to ensure the dead whale (a Bryde’s whale as it happened) was made safe and then mobilise a film crew; the only problem was that Hugh was filming turtle hatchlings in the Comoros Islands.

The following excerpt is about Mozambique’s Bazaruto Archipelago:

Five species of sea turtles haul out to nest here from October to December.

Author: XYuriTT

Animals of A Bygone Era

Title: Animals of A Bygone Era
Author(s): Maja Säfström
Release year: 2017
Publisher: Ten Speed Press

Why in Database: Turtles appear in this book in the form of a single entry, dedicated to the species cylindraspis vosmaeri. There are three texts below (note, the third text is our Translation from Polish versin, we don’t have access to the original version) and a picture, this graphic is also on the back cover.

They had super-long necks like this!!

They lived on an island near Madagascar

Giant tortoises of the species cylindraspis vosmaeri were friendly animals that usually lived in large groups.

Author: XYuriTT

Evolve or Die

Title: Evolve or Die
Original title: Evolve or Die
Author(s): Phil Gates
Release year: 1999
Publisher: Scholastic UK

Why in Database:A book from the Horrible Science series. It’s about evolution, soDarwin and the Galapagos Turtles couldn’t be missing! Turtles appear abundantly in the fragment about him, they are mentioned in 3 other places in the book, besides that, in the visual layer, they are found on many graphics. We present all this below:

Pterosaurs soared overhead, while Ichthyosaurs and giant turtles cruised the oceans.

Charles Darwin belched contentedly and leaned back in his chair. He picked at a morsel of tortoise flesh that had stuck between his teeth.
”That made a tasty meal, Captain Fitzroy,” he said. ”But I wish we could have taken the giant tortoises home alive.”
(…)
”I’m sorry, Darwin, but there’s just no room for any more live animals. Look around you. Where could we put six giant tortoises?”
Darwin eyed Fitzroy’s hammock, but said nothing. His gaze shifted idly to the pile of empty tortoiseshells. Each one came from a different island in the group of Galapagos Islands that they had just left behind. Suddenly Darwin noticed something that he hadn’t spotted before. Each shell had a slightly different pattern. Why? he wondered.
He pondered the question for some time before a thunderous thought hit him. His jaw dropped. His eyes glazed over. The jars of preserved specimens swam before his eyes.
The penny finally dropped. It was the Galapagos tortoises that set Darwin’s mind racing. Could it be that a single type of tortoise had originally landed on one island, swimming across from the coast of South America? And could it be that its descendants changed a bit, every time they’d colonized a new island? Each island was a bit different, with different kinds of plants growing on it, so maybe the tortoises that lived on each island needed to be a little bit different too.
Suddenly, it all seemed to make sense. He thought back to the birds that he’d seen on the islands. There were little brown finches on every island, and each island had its own special versions of these birds. They were all basically the same, but each species on each island had a slightly different beak shape. Perhaps they’d all evolved from the same species which had arrived on one island then evolved a bit when it spread to the others.
As they sailed home Darwin became certain that you could tell which island a tortoise came from by the pattern on its shell. They probably had other tell-tale atures too, but unfortunately it was too late to find out. They I loaded some live giant tortoises on board HMS ‘d Beagle, and he and Fitzroy had eaten them.
Still, it looked suspiciously like all the different types of tortoise had evolved from a single ancestor. Darwin began to wonder whether all kinds of living things had evolved in the same sort of way.
The differences between the tortoises were quite small, but later he began to wonder whether evolution could explain bigger differences between species too? Could fish have wriggled out of the sea, grown legs and evolved into amphibians like newts and frogs?

GALAPAGOS GUIDE BOOK
The Spanish discovered these Islands in 1535. They found giant tortoises there, so they called them the Galapagos Islands after galapago, the Spanish word for tortoise.
The Islands were created by undersea volcanic eruptions, 960 km west of the coast of Ecuador in South Volcanoes still erupt there quite often.
The Islands were once a favourite holiday destination for pirates and buccaneers, who came for a bit of rest and relaxation after raiding South American cities. The peckish pirates were particularly partial to a glant tortoise barbecue on the beach.

Evolve or Die Fact File
NAME: Giant tortoise
HABITAT: The Galapagos Islands
A single Galapagos giant tortoise can weigh 250kg. It takes eight men to lift one.
Sallors used to ride on them for fun. Darwin discovered that their top speed was about four miles per day.
Eleven different species of Galapagos tortoise survive today, each on its own Galapagos Island. Sadly, there’s only one giant tortoise left on the Island of Pinta. He’s a male, called Lonesome George. A reward of $10,000 has been offered to anyone who can find a genuine female Pinta giant tortoise to keep Lonesome George company.

Sometimes animals can become castaways. They can get carried out to sa and end up stranded on islands. Remember those Galapagos giant tortoises, and Darwin’s finches that he found on the Galapagos Islands?

Nothing can bring back extinct species, but there’s still time to save tigers, Spix’s macaw, the Californian condor, the Madagascan serpent eagle, the ivory-billed woodpecker, the hawksbill turtle and the giant panda, which are all sliding towards extinction…


Author: XYuriTT

Blue Planet II

Title: Blue Planet II
Author(s): James Honeyborne, Mark Brownlow
Release year: 2017
Publisher: BBC Books

Why in Database: A book supplement to the nature series with the same name, with many many turtle elements! We found as many as 12 pictures and many fragments in the text. We quote them all below:

The Arrival
During the course of the day, dark, round shadows appear in the shallow inshore waters off beaches on the Pacific coast of Costa Rica. They are not inanimate rocks but living Olive Ridley sea turtles, and for several hours they sit motionless on the seabed, resting, maybe even asleep, conserving nergy prior to a coming event that will require a herculean effort.
By early evening, they begin to stir. They swim parallel to the shore, their small heads bobbing above the surface to catch a breath, before submerging for five minutes or so at a time as if preparing for the big moment. Then, at some unknown signal, they start to emerge from the sea. changing from animals that are totally at home in the water to animals that are very uncomfortable on land.
At first, there are just twenty or thirty hauling their heavy bodies out of the surf, but gradually numbers increase until the beach resembles a moving conveyor belt of round, grey boulders. Many thousands of turtles will be crossing the beach and throughout the night they will just keep coming because they have to. Sea turtles are an ancient group of reptiles that are still bound to the land for this one vital purpose-to lay their eggs- so mothers must cross the frontier between land and sea and, for several exhausting hours, leave the confines of the ocean. It’s a huge challenge, but despite the hardships, the rewards are worth it.
It is the rainy season on a dark night a few days before the three-quarter moon, and these female sea turtles have come to deposit their eggs in the black volcanic sand. It is known locally as the arribada (“arrival”), and it is rely one of the most traumatic thing female sea turtle has to do during her life. More used to being supported by the water, her heavy body pushes down painfully on her internal organs, including her lungs. She wheezes and coughs, and glutinous tears ooze down from the corners of her eyes.
She sniffs at the sand, and when it is the right consistency and dampness she starts to dig. Using her spade-like hind limbs, she excavates a pit the shape of a teardrop. Manoeuvring her bulk over the hollow, she lets out a huge sigh, and slowly and deliberately she deposits up to 100 eggs, each the size of a ping-pong ball. Then, using her front flippers, she covers them and, with one last gargantuan effort, hauls her body back to the sea.
If she was the only turtle on the beach, her clutch would be undisturbed and probably many of her embryos would develop successfully and later hatch out, but she is not alone. Thousands of other mothers are excavating the same stretch of sand, the late arrivals inadvertently digging up the eggs of the early birds. It is just what the egg thieves have been waiting for.
Black vultures, wood storks and great-tailed grackles are in the vanguard, and this is their moment. They squabble for the exposed nests, some even snatching the soft-shelled eggs at the very moment they are laid. Coatis, recognised by their erect, striped tails and long snouts, dig up buried eggs, Stray dogs and feral pigs join them, rooting around in the sand, yet there is plenty for all. During the course of a single arribada over several days, hundreds of thousands of females emerge from the sea, and they deposit tens of millions of eggs safely beyond the reach of the tide. With so many eggs, predator swamping’ means that the thieves cannot eat them all, and nesting at night reduces the risk of nest predation. Some babies will have a chance to grow.
When the mothers go back to the sea, they all head off their separate ways. Olive Ridley sea turtles are more at home in the open ocean alone than on the shore with thousands of others of their own kind, but before they hit deep water they must run a gauntlet of sharks and American crocodiles from a nearby estuary. Even if they get past and survive, the fishing nets are another danger. In the past, thousands of turtles were caught in fine-meshed shrimp nets dragged by trawlers; many were drowned, and the population dwindled. Now local fishermen must by law have nets with turtle-excluder devices that enable the turtles to escape. It means a few more will return to join the next arribada.

THE WAIT (opposite) Olive Ridley sea turtles are a solitary, open-ocean species. During the day, they wait just offshore, as if preparing for the transition from water to land.

ARRIBADA (below and overleaf) Thousands of female Olive Ridley sea turtles emerge from the ocean to deposit their eggs in the sand of a Costa Rican beach.

BEACH TRAVELLATOR (opposite) Latecomers arrive just as the early birds leave, the former often digging up the eggs of the latter.

MOB RULE (below) Despite the superabundance of turtle eggs, two black vultures still fight over possession. They steal eggs even before the mother turtle has had time to finish depositing and burying her clutch.

The Olive Ridley sea turtles are short-term visitors to the coast, but at Roebuck Bay on the west side of the Dampier Peninsula in Western Australia there are animals that take advantage of high tides over vast mud flats, rich in food.

While the fish and shrimps are exchanging audible brickbats, the local sea turtles are just waking up and getting ready to do battle.

Turtle Rock Health Spa
In any great city, the morning rush hour sees commuters racing to their destinations, and the coral reef metropolis is no exception. Time wasted is feeding time lost, but for some the first appointment of the day is a visit to the health spa.
An old female green sea turtle emerges from the coral overhang under which she has spent most of the night asleep, lodged firmly in place to prevent her from floating up to the surface between breaths. While inactive she can hold her breath for several hours, but now it is time to move, and move fast. She wants to be first at the spa, and for the moment there’s not another turtle in sight.
A sea turtle with algae covering its carapace and parasites on the softer parts of its body is going to be slower, less healthy and at a disadvantage compared to one without, so she heads for the wash-and-brush-up service provided by local cleaner fish. It would have been better to saunter. The disturbance has other turtles, and they’ve noticed she’s making a break for it. There is only room for one turtle at a time at the spa, so the race is on.
On the reef at Sipadan, off the coast of Malaysian Borneo, Turtle Rock is a world-famous cleaning station. It is an unusual undersea landmark because the rocky outcrop has a well-worn hollow in the top that has been eroded by countless generations of sea turtles checking in to be cleaned. The first to arrive receives the five-star treatment, so the queue can involve a bit of argy-bargy, as underwater cameraman Roger Munns found out:
‘Green turtles have a well-deserved reputation for being very docile, but they are not so friendly when they want their shells cleaned at Turtle Rock. They bite and headbutt each other in order to get the best spot. They’re very aggressive.”
When the other turtles catch up and crowd in, they bite the lead female’s flippers and generally make life difficult for her, but it’s all to no avail: the first in is the first to be spruced up. Bicolour blennies appear from their burrows in the coral, and dark surgeonfish hover expectantly, ready to service the first customer of the day. The blennies deal with the parasites and dead skin, while the surgeonfish nibble on the algae covering the turtle’s shell. With this arrangement, the fish get an easy meal and the turtle a smoother shell and clean skin, the symbiotic relationship between them known as ‘mutualism’, meaning both parties benefit. It’s another way for them both to gain an advantage in the city.

LATE ARRIVALS (above) On one occasion, the film crew had to wait for over four hours for the turtles to turn up and settle into the cleaning station, and all for a 20-second shot!

TURTLE ROCK (opposite) Normally docile green sea turtles become very aggressive towards competitors for acces to this often used cleaning station

In fact, scientists now think that some of the larger animals feeding on the seagrass, such as green sea turtles and dugongs, actually obtain much of their nutrients, not from the seagrass leaves themselves, but from the ‘micro-forest’ of epiphytic algae.

Seed-Spreading Turtles
Green sea turtles are carnivorous for the first part of their lives. As juveniles they feed on sponges, jellyfish, fish eggs, molluscs, worms, and crustaceans, but when they reach adulthood, they switch to a predominantly herbivorous diet, chomping on seagrass and algae, and that’s not all. Aside from regularly trimming the seagrass meadow, they appear to have an important role in spreading it. It was once thought that only ocean currents dispersed seagrass seeds, but evidence is accumulating that turtles, and some of the other seagrass consumers, are at least partly responsible. The average green turtle eats about 2 kilograms of leaves and defecates about 25 seeds a day, and turtles tend to return to areas where seagrass traditionally grows, so they reseed old grounds as well as starting new ones.
Furthermore, in the laboratory, seeds germinate faster after having passed through the turtle’s gut. Seagrasses evolved about 100 million years ago and turtles have been eating seagrass for close to 50 million years, so it is possible the two species have co-evolved.
There is always the danger, of course, that an overly large population of turtles would strip out all of the seagrass, whether they replant it or not, but nature has an answer for that too. Tiger sharks protect the seedlings by keeping turtles in check!

UNDERWATER MOWER (above) An adult green sea turtle chomps on seagrass. It bites off the tips of the blades of grass with its serrated jaw, which, like a well-mown lawn, keeps the meadow healthy.

The shark patrol the lush parts of the seagrass meadows because that is where they expect the turtles and dugongs to be feeding, but the prey is smarter than that.

One was filled with 28,800 bathroom toys – plastic yellow ducks, green frogs, blue turtles and red beavers – but it burst apart, spilling its contents into the sea.

In the Pacific, a jellyfish-eating leatherback sea turtle embarked on the longest turtle migration ever recorded. It travelled 20,558 kilometres from its nesting beach on Papua in the southwest Pacific to jellyfish-rich feeding areas off the coast of Oregon in the northeast Pacific, and was on its way back when its tracking signal was lost. Like all marine reptiles, they must surface to breathe and so a turtle’s head popping out of the water might well be the source of many ‘sea serpent’ sightings in northern waters.

Lost Years and a Log
The fallen bough, washed into the sea by a river or toppled from coastal cliffs, becomes encrusted with barnacles and algae, and young sea turtles come to feed on them. The log is their temporary life raft, and their presence here has solved a long-standing biological mystery. When turtle hatchlings leave their beach, they head out into the open ocean and are probably faced with the most challenging times of their life, what scientists have dubbed the ‘lost years’ because nobody knew where they went until they returned to lay eggs five years later. Now we know.
‘We stumbled on the answer without fully realising it, John Ruthven reveals. ‘More than 160 kilometres off the coast of eastern Australia, with 3 kilometres of clear water below, we spotted a floating log. Diving below it, we found many creatures hiding, including a young hawksbill sea turtle not little, not large, but middle-sized. This is probably where it spends its so-called ‘lost years’.
‘Scientists can trace the paths of small turtles like this using miniature satellite tags. They show that hatchling turtles go far out to sea, and temperature sensors on the tags reveal that the little reptiles keep warm and develop faster by staying close to the surface, sheltered by floating objects.
‘After hatching, a baby turtle faces a daunting gauntlet of predators near the coast, and so it takes its chances on the high sea. When some inquisitive oceanic whitetip sharks came by, I wondered if this wasn’t much of a choice, but anything a turtle can do to improve its one-in-a-thousand odds of reaching adulthood must be useful,’
The young sea turtles ride the ocean currents, like many young marine creatures, hiding beneath flotsam, jetsam, logs and rafts of floating seaweeds, such as those found in the Sargasso Sea, part of the North Atlantic Gyre. Here, drift lines of Sargassum, a type of brown seaweed kept afloat by airbladders, are host to their own specialist community of animals, like the sargassum crab and the exquisitely camouflaged sargassum fish. These are the preferred hiding places for young turtles, but these miniature hotspots also attract unwelcome guests, and the predators of the open ocean are amongst the most inquisitive, none more so than the oceanic whitetip shark, which John had seen prowling.
At the slightest hint of food, the oceanic whitetip swims in directly and without fear. It may not have fed for weeks, so it wastes no time. It prefers fish to turtles, so an attack would be an exception, but there is another large and dangerous species with chainsaw-like teeth that would make easy work of a young sea turtle’s shell, and it deliberately targets these ocean drifters. It’s the tiger shark, thought until recently to be mainly a coastal species. However, tagging studies have shown that tiger sharks from the Caribbean head out a short distance into the Atlantic each summer in search of young, naïve and easy-to-catch loggerhead turtles.

OCEAN HIDING PLACE (below) A young sea turtle finds refuge amongst a floating mat of sargassum.

Garbage Patch Ocean
At one time, the debris in which young sea turtles hide was mainly natural, but nowadays a flood of plastics dominates. It is thought that the equivalent of a large garbage-truck-load of plastic is dumped into the sea every minute of every day. The effects are an ecological nightmare.
Thousands of sea turtles are either strangled by discarded nylon fishing gear or choke on plastic bags, mistaking them for jellyfish. It is estimated that over half of living turtles have eaten plastic at some time in their life, and about 90 per cent of seabirds have consumed plastic particles that they have mistaken for food.

PLASTIC JELLYFISH (opposite top) A green sea turtle mistakes a clear plastic bag for a jellyfish off the coast of Tenerife.

Lo and behold, the fossil skeletons of plesiosaurs and ancient sea turtles that lived about 100 million years ago have been found with the tell-tale excavations of zombie worms.

Plastic bags and the larger pieces of plastic block the intestines of whales, sea turtles and birds, such as albarosses, or kill chicks because their parents have fed them plastics.

Author: XYuriTT

Walking with Dinosaurs: A Natural History

Title: Walking with Dinosaurs: A Natural History
Author(s): Tim Haines
Release year: 1999
Publisher: BBC Books

Why in Database: A book directly related to the television nature series with the same Title. Of course, it focuses on dinosaurs, but there are also some turtle elements. The turtle shell is visible in one photo, the outline of the turtle is also shown in the graphic showing the diversity of reptiles. In addition, there are text mentions on several passages in the book, all of which we quote below:

When reptiles first appeared they formed three main groups distinguished by different types of skulls. Today this forms live in turtles, birds and crocodiles, and mammals.

The need to crawl out of the water every year and bury eggs, as turtles do, must have prevented the ichtyosaurs’ ancestors from exploiting the water fully.

But at the same time all four of their limbs were dedicated paddles (turtles have retained stumpy hind limbs for digging holes to lay eggs) and no plesiosaur or pliosaur eggs have ever been discovered.

There, in the middle of the beach, is the decaying body of a huge turtle. The Eustreptospondylus bends down and pushes his head into the half-empty shell. With a tug he draws out a large blob of meat and starts to feast.

In the 1970s American paleontologist Jane Robinson studied the muscle attachments of the flippers and concluded that they worked like underwater wings, powering the reptiles through the water just as the flippers of penguins or turtles do today.

He heads once again for the cove where he found the roting turtle, and he crosses the headland, the source of the new odour becomes apparent.

Crocodiles, lizards and turtles, for example, have no facial muscles; mammals are unique in having such expressive muscular faces, of which cheeks are an integral part.

Being cut off from the marine environment by the cliffs, these lakes have developed unique residents. In particular, they are dominated by large, predatory turtles. Most of the time these unlikely killers litter the beaches, sunning themselves, and seem somewhat slow and cumbersome compared to other aquatic predators. But in the dark waters of the lakes they are highly effective ambush hunters and few fish escape their powerful jaws.

The Ornithocheirus suddenly finds himself sharing his island with numerous big black turtles. He tries wadding away from them, but soon day is not warm enough for him to soar, therefore he takes off and flaps his way slowly to a turtle-free piece of shore.

However, other mammals, crocodiles, turtles, frogs, salamanders and numerous other marine organisms survived relatively unscathed.


Author: XYuriTT

Planet Earth II: A New World Revealed

Title: Planet Earth II: A New World Revealed
Author(s): Stephen Moss
Release year: 2016
Publisher: BBC Books

Why in Database: A supplementary book for the nature series Planet Earth II. There are several turtle fragments and two full-page photos.

The first turtle reference is in a foreword by David Attenborough:

It was a blissful time for those of us making natural history programmes. Even in Africa, where many of the animals were so familiar, we could easily find creatures that were quite new to most viewers – porcupines, chameleons and turtles. And if we went to other continents there were all kinds of astonishments – wombats and narwhals, hummingbirds and armadillos, manatees and sloths.

The jaguar is an excellent swimmer and, like most big cats, an opportunist, hunting a wide range of prey, from freshwater turtles and armadilos, to capybaras and deer.

In the absence of of their old predators or competitors, many animals (and plants) have developed unusual characteristics. Some are bigger than their mainland cousins – the Galapagos tortoises, for example.

The biggest tortoise

Small may not always be the best route to survival on an island, and many creatures display the opposite trait: they become giants. Nowhere is this more apparent than on the Galápagos Islands. Off the Pacific coast of South America, straddling the equator, the Galápagos gained their worldwide fame as the cradle of evolutionary theory when Charles Darwin visited in the 1830s. Observing the strange life forms he encountered, adapted to different situations, led him to develop his theory of evolution through natural selection.

Of all the creatures he came across, few were as impressive as the giant tortoises. They weigh on average roughly the same as three grown men. Once, these huge reptiles roamed across many of the world’s continents, but today they are only found on two island groups, separated by thousands of miles of sea: Aldabra in the Indian Ocean, and the Galápagos, where they live on 7 of the 21 islands. These reptiles are not only huge but also among the longest lived of any animal surviving more than a century in the wild (up to 170 years in captivity). Of the 13 known races, 11 survive today.
Like many of the other creatures on the Galápagos, the giant tortoises were castaways, drifting across the ocean from mainland South America. They managed to travel such a distance – some 1000km (620 miles) – because they float and can survive for several months without food or water. Helped by ocean currents, though some would have drifted westwards, enough made landfall for a viable population to become established.
Darwin was stunned by the size of these reptiles, noting in his journal that it took up to eight men to lift a tortoise. So why are they so big? One theory suggests that only the largest tortoises could have survived such a difficult sea crossing, as their large volume to surface area ratio would have allowed them to retain fluids, while their longer necks meant they could breathe more easily.
The other notable feature is how the shape of their shells differs. The shapes seem to correlate with the habitat of the island on which they live: those on lush, well-vegetated islands have domed shells and shorter necks; those on dry, desert-like islands have ‘saddleback’ shells and long necks. Presumably, where there is plenty of low-growing vegetation, the animals can easily reach their food, while on drier islands, they may need to reach up to get to taller vegetation such as the abundant prickly pear cactus. However, other scientists have suggested that this may be a coincidence and that the saddleback shell shape is actually a product of sexual selection, a result of generations of females preferring males with a higher front to their shell and longer necks. But then two races that have a similar shape may not necessarily be very closely related, which tends to suggest that they have evolved in response to the type of habitat in which they live.
Famously, at the time of his visit, Darwin falled to appreciate the differences in shell-shape between each island tortoises. Only when he returned to England did he develop his theory; and then, to his eternal regret, he found that he had not always labelled the tortoise shells he had collected with the name of the island where it had been found – thus making the specimens far less useful for determining whether his assumptions were correct.
When the islands were discovered in the sixteenth century there were as many as a quarter of a million giant tortoises; today there are just a few thousand. But with better habitat conservation, and the removal of introduced animals, their future now looks more assured.

The text below is a description of the picture of the Aldabra tortoise, which is shown next to the long text quoted above:

The biggest survivor. Aldabra giant tortoise, on the remote Indian Ocean atoll of Aldabra – part of the Seychelles group. It is more than a metre long (more than 3 feet), and is the only species of giant tortoise to have survived in this part of the world, the others having been hunted to extinction by visiting seafarers or settlers or their habitat destroyed by introduced animals accompanying humans. These giants can live for more than 100 years, probably more than 150.

So long as the niche you fill is unocuppied, it makes sound evolutionary sense to be either tiny or, if you are a tortoise on the Galapagos or Aldabra, very large indeed.

Turtles have been coming to Barbados to lay their eggs for thousands of years, but now light from the holiday resorts is throwing the hatchlings off track. On emerging, they need to head to the water as fast as they can to avoid being picked off by predators such as gulls. They have evolved to head to the brightest horizon – the water reflecting the light of the moon. But today the brightest glow comes from the hotels and restaurants, which takes the hatchlings in exactly the wrong direction. Red crabs then gather under the streetlights, picking them off before they ever reach the sea. For these turtles, which have seen urbanization take over their once-pristine natural nurseries, the future would be bleak were it not for the conservationists who are helping the hatchlings make it to the sea.

The caption for the second turtle photo in the book, with a leatherback turtle, placed next to the text above:

Lure of the nightlight. On Juno Beach, Florida, a leatherback sea turtle hauls up to lay her eggs. When the baby turtles hatch, they head for the brightest horizon, which should be the natural glow of moon on the sea. But light from beachfront development can lead them off course, and wandering hatchlings can be hit by cars or caught by predators.

On the Caribbean island of Barbados (as on the beaches elsewhere), hatchling turtles are so confused by the lights of beach developments that they head away from the sea rather than towards it, and the shoots at night mostly recorded baby turtles dying in street gutters.

Author: XYuriTT