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1、www.readinga-SeaTurtlesSea TurtlesA Reading AZ Level R Leveled BookWord Count:1,564Visit www.readinga- for thousands of books and materials.Written by Kira Freed Illustrations by Cende HillLEVELED BOOK RWritten by Kira FreedIllustrated by Cende HillSeaTurtlesSea TurtlesLevel R Leveled Book Learning
2、AZWritten by Kira FreedIllustrated by Cende HillAll rights reserved.www.readinga-Photo Credits:Front cover,back cover,pages 4,18:National Oceanic and Atmospheric Administration/Department of Commerce;title page,page 13:OAR/National Undersea Research Program,University of North Carolina at Wilmington
3、,National Oceanic and Atmospheric Administration/Department of Commerce;pages 5,20:PhotoDisc;page 16:Courtesy of NPSCanaveral National Seashore,National Oceanic and Atmospheric Administration/Department of Commerce;page 17:Dr.James P.McVey,NOAA Sea Grant Program,National Oceanic and Atmospheric Admi
4、nistration/Department of CommerceCover photo:Hawksbill sea turtleThis book is dedicated to Nehemiah Stark,who shares my love of sea turtles.www.readinga-CorrelationLEVEL RN3030Fountas&PinnellReading RecoveryDRA34Table of ContentsIntroduction.4Types of Sea Turtles .6Physical Appearance .12Nesting .15
5、Hazards.20Protecting Sea Turtles.22Glossary .26IntroductionSea turtles have roamed the oceans for at least 150 million years.They are among Earths oldest surviving animals,having lived during the time of the dinosaurs.Like dinosaurs,sea turtles are reptiles,and like all reptiles,sea turtles are cold
6、-blooded.They have scaly skin,breathe air,and have a heart with three chambers.HawksbillSea Turtles Level R56Sea turtles have many living turtle relatives,including freshwater turtles,snapping turtles,tortoises,and soft-shelled turtles.All of these turtles live either on land or in freshwater.Sea tu
7、rtles are the only turtles that live in the saltwater of the worlds oceans.Types of Sea TurtlesSea turtles are divided into two types.One type,called the leatherback,is covered with leathery skin.Beneath this skin is a shell made of cartilage and thousands of tiny bones.The cartilage forms prominent
8、 ridges that give the leatherback its unique appearance.The leatherback is the largest of all sea turtles and the most widely distributed.It lives far out to sea except during breeding season.Desert tortoiseLeatherbackBox turtleSea Turtles Level R78All types of sea turtles other than the leatherback
9、 have a shell made of bony plates,or scutes.The top part of the shell is called the carapace.The part of the shell under the turtles belly is called the plastron.These two parts are connected to the muscles and bones inside the turtles body.The number and pattern of the scutes is helpful in identify
10、ing the type of sea turtle.The green turtle is a medium to large sea turtle with a shell that has mottled markings.The green turtles head is small relative to its body when compared with other sea turtles.It lives in many oceans around the world.The black turtle is sometimes called the Pacific green
11、 turtle.Researchers disagree on whether it is a type of green turtle.The black turtle is dark gray with stripes of other dark colors.It lives on the west coasts of North and South America.The black turtle prefers to live in warm bays and protected shores,and is rarely found in the open ocean.carapac
12、eplastronDo You Know?Unlike a land turtle,a sea turtle cannot pull its limbs or head into its shell.Black turtleGreen turtleSea Turtles Level R910The loggerhead turtle is a large reddish-brown sea turtle.It has an extremely large head for the size of its body.Loggerheads live along the coast in trop
13、ical and subtropical waters around the world.The hawksbill is a small to medium sea turtle with a hawklike beak.Its shell has a distinctive pattern of thick,overlapping brown scales.It lives in and around shallow coastal waters in and around coral reefs.Olive ridleyKemps ridleyKemps ridley,one of th
14、e smallest sea turtles,has an oval shell that is black during juvenile years,changing to olive gray during adulthood.The Kemps ridley has one of the most restricted ranges of all sea turtles.Adults are rarely found outside of the Gulf of Mexico,and almost all Kemps ridleys nest on a five-mile stretc
15、h of beach in Mexico.The olive ridley,another small sea turtle,is similar to the Kemps ridley.However,its shell is thinner and its head is smaller.The shell is heart-shaped or round,and may be gray-brown,black,or olive green.The olive ridley lives in coastal tropical regions of the worlds oceans.Log
16、gerheadHawksbillSea Turtles Level R1112The Australian flatback lives in shallow waters off the coast of northern Australia and Papua New Guinea.It stays close to the shore,never venturing into the open ocean.It prefers to live around coral reefs and grassy inlets.The Australian flatback has a flat b
17、ody with a smooth shell that is olive gray with lighter edges.Physical AppearanceSea turtles vary greatly in size.The largest is the leatherback,which can grow as large as 2.2 m(7.2 ft)and weigh up to 700 kg (1,500 lbs).The smallest sea turtles are the olive ridley and Kemps ridley.They may measure
18、up to 71 cm(28 in)and weigh up to 45 kg(100 lbs).Adult male and female sea turtles of each species are equal in size.Olive ridleyDo You Know?The largest leatherback ever recorded weighed over one ton.Australian flatbackLeatherbackSea Turtles Level R1314Sea turtles are strong,graceful swimmers and di
19、vers whose streamlined bodies are well adapted to life in the ocean.Long front flippers provide the power for propelling through the water.The hind flippers are used as rudders for steering.When sea turtles are active,they need to return to the waters surface every few minutes in order to breathe.Wh
20、en resting or sleeping,they can remain under water without breathing for two hours or more.Like all turtles,sea turtles have jaws that are beaklike in shape and lack teeth.The unique jaw shape of each species is an adaptation to its unique diet.Some sea turtles are carnivorous(meat eating),some are
21、herbivorous(plant eating),and some are omnivorous(eating both meat and plants).Green sea turtles are herbivorous as adults.Leatherbacks feed mainly on soft-bodied animals such as jellyfish.Loggerheads eat crabs,jellyfish,and mollusks.HawksbillSea turtles have beaklike jaws.Sea Turtles Level R1516Nes
22、tingSea turtles live almost their entire lives in water.Females come onto sandy beaches mainly to lay their eggs.Sea turtles are awkward and slow-moving on land,as well as being nearsighted.Because of this,they are more vulnerable to attack by predators while on land.Most females return to the same
23、nesting beach every year.They come ashore at night,alone,usually during high tide.A female chooses a spot above the high tide line so her eggs will not get washed away.With her front flippers,she digs a pit for her body,then digs an egg cavity with her hind flippers.LeatherbackDo You Know?A male sea
24、 turtle may live its entire life without ever coming on land.Sea Turtles Level R1718The female sea turtle lays her eggs in the egg cavity.Depending on the species,she may lay between 50 and 200 eggs.The eggs,which look like Ping-Pong balls,have soft shells and do not break as they fall from her body
25、.When the female has laid her eggs,she uses her hind flippers to cover them with sand.The sand keeps the eggs hidden from predators and keeps them warm so they will incubate.When a female sea turtle comes on land to lay her eggs,she often looks as though she is crying.This is because of a gland that
26、 helps rid her body of excess salt.While on land,the“tears”help to keep sand out of her eyes while she is digging her nest.An egg from a sea turtle nestA female loggerhead returns to the ocean after laying her eggs.Her eyes are free of sand because of the“tears”she has cried.Do You Know?Sometimes a
27、female crawls onto land but for unknown reasons,decides not to nest.This is called a“false crawl.”Sea Turtles Level R1920HazardsAdult sea turtles have few natural enemies.Sharks are the main predators,especially tiger sharks.Sea turtle eggs and hatchlings are eaten by fish,dogs,seabirds,raccoons,gho
28、st crabs,and other predators.More than 90 percent of hatchlings are eaten by predators.Only about 1 in 1,000 sea turtles survives to maturity.HawksbillDo You Know?Sea turtle eggs do not start out male or female.The temperature of the surrounding sand helps to determine the sex of the hatchling.Hot s
29、and produces more females,and cool sand produces more males.Many kinds of predators feast on sea turtle hatchlings.Sea turtle eggs hatch between 45 and 70 days after being laid.Hatchlings usually wait until night to emerge from the nest.They are very vulnerable to predators when they first hatch.Nig
30、httime is a safer time for them to make their way to the water.Still,many hatchlings do not survive the trip to the ocean.Sea Turtles Level R2122The most serious dangers to all kinds of sea turtles come from human impact.Nesting areas are scarce because of building construction along beaches.Lights,
31、noise,trash,and activity on beaches can discourage adult females from coming on shore.All of these things also confuse hatchlings,who may accidentally head away from the ocean instead of toward it.Some sea turtles die from eating trash.Leatherbacks often mistake plastic for jellyfish and die when it
32、 clogs up their digestive system.Sea turtles can also die from injuries caused by collisions with boats.Protecting Sea TurtlesThousands of sea turtles drown each year in shrimp nets.United States law requires shrimp fishermen to use a Turtle Excluder Device(TED)on all shrimp nets,which is a trap doo
33、r inside the shrimp net that allows sea turtles to escape.TEDs have saved the lives of many turtles.However,some shrimp fishermen do not follow the law.Shrimp nets without TEDs continue to be a danger to sea turtles.Shrimp trawling net with Turtle Excluder Device(TED)shown in boxA female sea turtle
34、is discouraged from nesting because of buildings and oceanside development.(left)The turtle and shrimp enter the TED.(right)The shrimp are small enough to shoot through the bars and into the net.The turtle slides down the bars and hits a flap,which then opens to release the turtle.Sea Turtles Level
35、R2324Sea turtles are also hunted for their shells,which are used to make combs,eyeglass frames,and souvenirs.Another danger to sea turtles is the illegal collection of their eggs for food.Green turtles and other sea turtles are also hunted illegally for their meat.All eight species of sea turtles ar
36、e threatened or endangered in the United States.It is illegal to harm or interfere with a sea turtle or its eggs.An international treaty protects all species of sea turtles,and over 100 countries have banned the import or export of sea turtle products.Still,many people break laws or are careless.Sea
37、 turtle protection must be improved considerably if they are to survive into the future.Signs like this one warn people to avoid sea turtle nests.Many people in many countries are working to keep sea turtle numbers from dwindling.Volunteers in many nesting areas put screens over the nests to keep ou
38、t predators,and post warning signs to alert beachcombers to the presence of nests.Eggs laid too close to the water are often moved to higher ground.People are also working to protect important nesting sites by making them wildlife refuges.Also,many clinics help to rescue and give medical attention t
39、o injured sea turtles.Sea Turtles Level R2526Some zoos and aquariums have captive sea turtles.Sea turtles are much happier in the wild.But it is also good for people to learn about sea turtles and watch them up close.People can also learn about the many hazards to sea turtle survival caused by human
40、s.Hopefully,enough people will care about sea turtles to preserve their habitats and help them to survive.Glossarycarapace the top of a turtles shell(p.7)carnivore an animal that eats only meat(p.14)false crawl when a female sea turtle comes onto land but returns to the ocean without nesting(p.18)herbivore an animal that eats only plants(p.14)omnivore an animal that eats both plants and meat(p.14)plastron the part of a turtles shell underneath its belly(p.7)scutes the bony plates that make up a turtles shell(p.7)People enjoy watching and learning about sea turtles.Sea Turtles Level R