"'CARD 31 PUFF ADDER

The puff adder is one of Africa~ most feared venomous snakes. When threatened, this thickset viper puffs itself up and hisses

loudly before it strikes and possibly kills its attacker.

KEY FACTS

SIZE

Length: 2-5 ft.

BREEDING

Sexual maturity: About 2 years.

Breeding season: October to

December.

No. of young: 20-30. May be

more than 50.

Incubation: About 5 months. Eggs

usually hatch inside the female.

LIFESTYLE

Habit: Solitary; mainly nocturnal.

Diet: Various small mammals,

birds, amphibians, and reptiles.

Lifespan: Maximum on record, 15

years in captivity.

RELATED SPECIES

There are 8 species in the genus

Bitis. The longest is the Gaboon

viper, Bitis gabonica, and the short­

est is the dwarf viper, B. peringueyi.

Range of the puff adder.

DISTRIBUTION

The puff adder is found throughout most of the African conti­

nent. It lives everywhere except at heights of over 6,500 feet,

in the rainforest interior, and in the most arid deserts. Its range

extends into the Arab peninsula.

CONSERVATION

Although it is hunted by other predators, and it is feared by

humans, the puff adder is not in any immediate danger.

FEATURES OF THE PUFF ADDER

Head: Broad, flattened, and spear­shaped. Distinct from the rest of the body. Contains large jaw muscles and venom-producing glands.

Fangs: Sharp, . hollow tubes through which venom passes into the victim's body. When not in use, the fangs fold back inside the mouth.

,-

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Skin: Covered with rough scales that dull the snake's colors. The colors vary depending on habitat, but most snakes are marked with V-shaped bands. The female is more brightly colored than the male.

Body: Thickset. Its belly is flat, and its sides slope down in a triangular shape. Its tail is easily distinguished. The male is smaller than the female.

0160200611 PACKET 61

The puff adder's coloring varies to match

the sand or soil of its habitat. This camouflage helps

the snake to hide from predators and to ambush its prey

successfully. On the other hand, this excellent adaptation

makes the snake difficult for humans to notice. Many

people have been bitten and seriously poisoned after

treading on a well-camouflaged puff adder.

~ HABITS The puff adder is widely distrib­

uted throughout most of Africa.

It lives in a variety of habitats,

from deserts to tropical forests.

It may stray onto farmland and

prey on chickens and on the rats

it finds in grain storage areas.

The puff adder is usually about

three feet long with a thick body

and broad head. As it moves for­

ward, it keeps its body straight,

contracting muscles on its belly

to push its rough scales against

the ground. This is known as

rectilinear movement.

The puff adder is active mainly

at night when it feeds. During

the day it may climb into a shrub

to bask in the sun, especially if it

is pregnant. The snake may go

into water and at night often

lies on tarred roads that retain

heat from the sun.

The adder may be attacked by

birds of prey, mongooses, wart­

hogs, and other snakes. When

disturbed, the snake inflates it­

self and hisses. If necessary, it

raises the front of its body into

an S shape and lunges.

~ BREEDING The puff adder breeds between

October and December. The

male snake engages in "com­

bat dances" with other males

to win the right to mate with a

particular female. When mat­

ing, he curls his tail beneath

the female's and inserts his sex

organs into a cavity at the end

of her body called the cloaca. Fertilized eggs remain inside

the female until March or April.

The eggs are thin and often

tear as they are being laid, so

the young snakes have usually

hatched by the time they leave

the mother's body. Snakes that

Left: The puff adder transfers scent from its tongue to the Jacobson's organ, a scent organ in its mouth.

DID YOU KNOW? • The puff adder causes over half of the serious snake bites

inflicted on humans in Africa.

• The puff adder produces 100

to 350 milligrams of venom.

Just 100 milligrams is enough

to kill a human.

• The puff adder stores a great deal of body fat. Local doctors

collect the fat and use it as a

give birth to live young in this

way are called ovoviviparous. Usually 20 to 30 young are

born at once, although births

of over 80 snakes have been re­

corded. The young are about

eight inches long and can im­

mediately kill small animals

such as mice and rats. At first,

however, the young usually do

not hunt. Instead, they molt (shed their skin) and feed off

the yolk sac with which they

are born. During this time they

grow longer and wider. By the

age of two, the puff adder is

sexually mature.

Right: The puff adder is solitary. The male and female do not stay together after mating.

treatment for rheumatism.

• In 1964 the director of the Salt Lake City Zoo died from

a puff adder bite.

• There is a deep pit above the puff adder's nostrils, but its pur­

pose remains a mystery.

• The Cape puff adder sub­species lives only in a small

mountain area in South Africa.

~ DEFENSES The puff adder's variable color­

ation is a vital adaptation to its

environment. Desert-dwelling

adders are light yellowish brown

with dark brown, pale-edged

chevrons (V-shaped bands). In

tropical forests puff adders are

dark brown with brown and

olive patterns that offer camou­

flage in the leaf debris.

~ FOOD & FEEDING The puff adder preys mainly on

small mammals, but it also at­

tacks birds, amphibians, and

lizards. Camouflaged by its col­

oring, the snake may remain

motionless for several hours,

waiting for prey to come with­

in striking distance.

The puff adder does not need

to use its venom on small prey

such as frogs, which it can seize

in its jaws and swallow alive. It

Left: The puff adder's fangs fold back on elastic hinges to allow prey to be swallowed.

If it is discovered by a preda­

tor, the adder hisses loudly and

backs away. If this defense fails,

the snake strikes. A potent ven­

om is pumped from glands in

its head, through its fangs, into

the victim's body. The area near

the bite burns, swells, and blis­

ters. Fatal heart or kidney failure

usually follows.

bites larger prey with its fangs

and injects them with deadly

venom. The venom takes time

to affect its victim, so the ani­

mal may flee before dying. The

puff adder then follows the trail,

finds the corpse, and eats it.

When eating, the puff adder

seizes its prey with the teeth in

its lower jaw and swallows the

animal whole. It keeps its head

up, while muscular movements

carry the food down to its stom­

ach. A long period of rest and

digestion follows.

'" CARD 32 SLOWWORM "~ ____________________ G __ RO_U_P __ 3:_R_E_P_TI_l_ES_& __ A_M_P_H_IB_I_A_N_S_~~

ORDER FAMILY GENUS &; SPECIES Squamata Anguidae Anguis fragi/is

The slowworm may look like a snake, but it is really a lizard without any legs. If it is alarmed, it may shed its tail

in order to distract an attacker.

'\l KEY FACTS

I~ I SIZES ~ Length: 11-12 in . at maturity,

but may continue growing to a

maximum of 20 in.

BREEDING

Sexual maturity: Male, 3 years.

Female, 4-5 years.

Mating season: Spring.

Gestation: From 4 months to

nearly a year, depending on

temperature.

No. of young: 6-12, occasionally

up to 20.

LIFESTYLE Range of the slowworm.

DISTRIBUTION Habit: Solitary in summer. Often

hibernates in groups.

Diet: Mainly slugs, snails, earth­

worms; also insects and spiders.

The slowworm is found throughout mainland Europe,

southern Scandinavia, Great Britain, and southwest Asia.

CONSERVATION RELATED SPECIES

The many snakelike lizards in the

family Anguidae include the large

European glass lizard and the

California legless lizard.

Although it is occasionally killed by people who think it is a

venomous snake, the slowworm is still common wherever its

habitat has remained intact.

HOW TO TELL A SLOWWORM FROM A SNAKE

The slowworm is a limbless lizard, not a snake. Here are some ways that snakes differ from slowworms.

Tongue:$nakes have long forked tongues (above) . Siowworms have notched tongues.

Scales: Snakes have rough scales (right). Slow­worms have smooth scales.

Eyes: Snakes have lidless eyes __ that cannot be closed (right). Siowworms have eyelids and are able to blink.

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When in danger, the slowworm can rupture special bones and shed its tail. Muscles and blood vessels also part to make a clean break.

The new tail is made of cartilage. It is shorter and contains no special bones, so the shedding action cannot be repeated.

0160200461 PACKET 46

The slowworm is one of several legless burrowing

lizards that are found in different parts of the world.

This elongated creature both looks and moves like

a snake, wriggling its highly polished muscular body

through soil and vegetation. Although it cannot

be said to move quickly, the slowworm is not

as lethargic as its name suggests.

The slowworm relies on the sun's heat to raise its body tem­perature until its muscles and internal organs work efficiently. It hibernates in winter, when the sun is weak and there is lit­tle food. Up to 30 slowworms may hibernate together in a burrow or under a rock, lying dormant until spring's warmth penetrates their retreat.

DID YOU KNOW? • One captive slowworm lived for 54 years. • A mature male slow­worm may have so many bright blue spots that it looks blue all over. • The slowworm's skin is embedded with bony plates, forming an outer shell that reinforces the bones within.

~ FOOD & HUNTING The slowworm prefers to hunt easy prey such as slugs, snails, and earthworms, but it occa­sionally takes insects and spi­ders. It is often welcomed by gardeners because it eats the small white slugs that cause damage to vegetables.

The slowworm is most active at twilight or after a rainfall,

Left: The slow­worm's skin is not slimy. The scales are dry and as smooth as polished metal.

Right: The slowworm usu­ally seizes prey by the middle of the body. Here it bears down on a net­tled slug.

~BREEDING The slowworm mates soon after it emerges from hibernation in April or May. The males com­pete for mates, seizing each other by the head or neck, entwining their bodies, and writhing over the ground. The act of mating looks similar but is less violent and damaging.

The pregnant female spends many hours in the summer sun, raising her body temperature to between 70 and 7l F to speed the development of her young. If the summer is warm, the young may be born in late August, but cool weather will

when slugs and earthworms are most numerous. Gliding up on its polished scales, it seizes its victim in its small mouth and slowly eats it. Unlike a snake, it cannot stretch its mouth around large prey, so anything larger than a small slug must be chewed thor­oughly before it is swallowed.

delay the birth until October or even the next spring.

The slowworm is ovoviviparous -the female produces eggs without shells that hatch inside her body. The six to twelve young are very active and can feed themselves almost imme­diately at birth, but they take several years to grow to their full size. The young are yellow on top and black on the bot­tom, with a dark stripe down the back. Upon reaching adult­hood they turn brown or sandy gray. The female's flanks and underside are darker.

~ DEFENSES Frogs and toads prey on young slowworms, and adults may be attacked by snakes, hedgehogs, foxes, and birds of prey.

If threatened, a slowworm tries to escape. But if necessary, it resorts to an extraordinary de­fense tactic-it snaps in two.

The tail bones nearest the body have weak areas that let

the bones snap cleanly and eas­ily. If alarmed, the slowworm ruptures the bones, and a por­tion of the tail is thrown off. For a few minutes the severed tail writhes convulsively, distracting the predator while its former owner escapes.

The stump heals quickly, and a new, shorter tail grows. The tail bones are not replaced and the new tail is made of carti­lage, so the slowworm cannot shed its tail again.

[g NATUREWATCH I The slowworm basks in full sun in spring but takes shel­ter from direct heat later in the year. It can often be found in compost heaps or piles of twigs. To the touch, the slowworm is dry with a glassy feel. If alarmed, it may shed its tail, reducing its future chances of survival.

~~3U

NORTH AMERICAN =~:=~AMPHIBIANS ~ '(~---------------- ~~~ ... CLASS ... ORDER FAMILY '" GENUS

'11IIIIIIII Amphibia '11IIIIIIII Salientia Hylidae '11IIIIIIII Hyla

North American treefrogs are a varied and colorful assortment of amphibians. They are known for their loud calls and can be

easily recognized by their enlarged, adhesive toe pads.

'S:J---'S..EY FACTS

I~ I SIZE ~ Length: ~-5 ~ in ., depending on the

species .

BREEDING

Sexual maturity: 1 year.

Mating season: Varies in different

parts of the country.

No. of eggs: Several hundred to

2,000, depending on the species.

Hatching time: 2-10 days, depend­

ing on the species.

Metamorphosis: 1-2 months.

LIFESTYLE

Habit: Solitary except in the mating

season, when large numbers congre­

gate in ponds and marshes.

Diet: Small insects and spiders.

RELATED SPECIES

There are 600 members of the family

Hylidae in the world and 14 species

of Hyla in North America. Cricket

frogs (genus Acris) and chorus frogs

(Pseudacris) are other North Ameri­

can members of this family.

Range of North American treefrogs.

DISTRIBUTION

Found from southwestern Canada and the Maritime Provinces

south to western Mexico and the Gulf Coast but absent from

the Great Plains.

CONSERVATION

Most North American treefrogs are still common in their ranges,

but they suffer from pesticides and habitat destruction, especial­

ly of wetlands. The pine barrens treefrog is a threatened species.

FEATURES OF NORTH AMERICAN TREEFROGS

Spring peeper, Hyla crucifer: Distinguished by its small size , tan colori ng, and the dark X-shape ...A .... on its back. Throat pouch: This

organ is inflated by the male to produce a sound that attracts a female .

Green treefrog, Hyla cinerea: Colored bright green, usually with a white stripe running down its side.

Gray treefrog, Hyla versicolor: Easily identified by its mottled coloring with dark blotches on a predominantly greenish or grayish background.

~~~~JIo};2:" '~'~!i;;~~~~~~~ Toe pads: The swollen tips ~ of its toes enable a treefrog

to cling to vertical su rfaces.

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North American treefrogs use their adhesive toe pads

to climb through foliage in search of insects. For most of

the year these small, well-camouflaged amphibians are

hidden in the woods and are rarely seen. But during the

mating season, large numbers gather near water.

~ HABITS There are treefrogs on almost every continent. The 14 species in North America range in size from the Cuban treefrog, which is more than five inches long, to the half-inch little grass frog .

The calls of some treefrogs, such as that of the well-named spring peeper in the East, are recognized as one of the first signs of spring . The Pacific tree­frog, which is abundant in the hills around Hollywood, has be­come known for its loud, two­part musical call . Its voice can

be heard on the soundtracks of many movies.

Outside the breeding season, most treefrogs are nocturnal, forest-dwelling hunters of small insects. To protect themselves from drying out in hot summer weather, some treefrogs coat themselves with a layer of mu­cus that seals in the moisture in their bodies. In winter, many species hibernate.

Above: The Pacific treefrog may be green, tan, or black. It is the most common treefrog on the West Coast.

I' >i1t.J NATUREWATCH North American treefrogs, such as the tiny spring peep­er, are most often seen dur­ing the mating season, when males and females emerge from the woods to mate and lay eggs in ponds and marshes. At other times of year, these frogs are secre­tive woodland creatures. But the males' distinctive calls may sometimes be heard in warm months outside the mating season-especially during a shower or immedi­ately after one.

~ BREEDING North American treefrogs spend most of the warm months hunt~ ing insects in woodlands. How­ever, once a year, usually in the spring, huge numbers gather in weedy ponds and marshes to mate and lay eggs.

The male of each species has a distinctive call, enabling the females of that species to rec­ognize him. When a female appears, the male grasps her just behind her front legs and fertilizes the clusters of eggs as

she lays them. Most species lay several hundred eggs, but a few lay up to 2,000.

The eggs hatch in two to ten days, depending on the species and on the temperature of the water. A tiny tadpole emerges from each egg. In one to two months, the tadpole metamor­phoses, changing into a small version of the adult. The young frog hops into the woodlands nearby and does not reappear until the next breeding season.

DID YOU KNOW? • The spring peeper's species name is crucifer, which means "cross-bearer." It refers to the cross on this tiny frog's back. • It has recently been discov­ered that the gray treefrog is not a single species, but rather two outwardly identical spe­cies that differ genetically. The rate at which they call is also different. Scientists have not yet determined the ranges of these two frogs . • The pine barrens treefrog is the rarest treefrog in North America. It lives in only a few

~ FOOD &: FEEDING North American treefrogs feed on a variety of insects such as flies, leafhoppers, and beetles. As their name implies, treefrogs hunt mostly in trees or bushes,

Left: The spring peeper is named for the high-pitched peeping sound it produces in the spring.

Left: The male gray treefrog is often heard ut­tering its loud, shrill trill from the trees. But, because of its mottled color­ing, the frog itself is usually difficult to see. The skin of the gray treefrog is wartier than that of most other treefrogs.

sandy areas with pines from New Jersey to the Carolinas. • The bird-voiced treefrog is a common southern species, with toxic skin secretions that can cause watery eyes and nasal congestion in people who handle it. • Most treefrogs are solitary nocturnal hunters. But the squirrel treefrog, which lives in the Southeast, frequently spends the day in a tightly packed cluster. The group's members conserve moisture by huddling together.

employing their sticky toe pads to cling to the leaves.

Like all other frogs, a treefrog catches its insect prey by quick­ly shooting out its tongue. The instant an insect sticks to the tongue, the treefrog pulls the tongue back in .

BUSHMASTER

CLASS Reptilia

ORDER Squamata

GROUP 3: REPTILES &: AMPHIBIANS FAMILY Crotalidae

~ GENUS &: SPECIES ~ Lachesis muta

The bushmaster is the largest venomous snake in the Americas. But despite its great size, it is rarely seen in the dense

vegetation of its rainforest habitat.

KEY FACTS

SIZES

Length: Average, 8-10 ft. Maxi­

mum, 12 ft. Weight: 6-11 lb.

BREEDING

Sexual maturity: 2 years.

Breeding season: Probably spring.

Eggs: About 10; white.

Hatching time: 9 weeks.

LIFESTYLE

Habit: Solitary. Conceals itself by

day; hunts by night.

Diet: Mainly small mammals.

Lifespan: 20 years or more.

RELATED SPECIES

The family Crotalidae includes

rattlesnakes, moccasins, and sev­

eral species of fer-de-lance. Most

crotalids are found in the Americas,

but some inhabit the Old World.

Range of the bushmaster.

DISTRIBUTION

Found in tropical rainforests in Central America and northern

parts of South America from Costa Rica to Brazil. Also occurs on

the island of Trinidad.

CONSERVATION

Because of the bushmaster's habitat and lifestyle, precise popu­

lation figures are not known. But it can be assumed that it is

suffering from the destruction of the rainforests.

FEATURES OF THE BUSHMASTER CARING FOR THE EGGS

Body: Slender, long (up to 10 feet), and almost triangular in cross sec­tion . The skin is covered in rough scales with knobby protrusions.

Coloring: Pale or pinkish tan with distinctive dark brown diamond­shaped pattern along the back. This provides camouflage among the dead leaves of the forest floor.

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Head: Large and wedge-shaped, tapering toward the front. Cov­

ered with small , irregularly shaped scales.

Eyes: Large vertical pupils

give good night­time vision.

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Laying: The female lays about 10 large white eggs in a hol­low in the ground . The eggs are larger than a hen's eggs.

Incubating: Unlike most other snakes, the female bushmas­ter guards the eggs by coiling her body around them until they are ready to hatch.

0160200571 PACKET 57

The bushmaster is one of a group of snakes

known as pit vipers. Like all of these snakes, the

bushmaster is equipped with special organs that detect

another animal's body heat, alerting the snake to passing

prey in the nighttime darkness of the forest. Once it has

located its victim, the bushmaster bends the front part of its

body into an 5 shape to make a lightning strike.

~ HABITS The bushmaster lives in tropi­cal rainforests or in forests on the lower slopes of mountains, where there is a minimum rainfall of 79 to 158 inches a year. The humid, dense jungles of South America provide the bushmaster with an ideal hab­itat, since it needs a warm, moist climate and prefers to avoid direct sunlight.

The shy bushmaster avoids contact with humans. During the day it hides in dense under­growth, where it is well cam­ouflaged against the dead leaves on the forest floor. It

emerges from cover only at night to search for prey.

Like most venomous crea­tures, the bushmaster uses its toxin only to kill prey. It de­fends itself by biting only in extreme cases, preferring to scare away its enemies rather than waste its precious venom. To deter predators, the bush­master thrashes its tail against vegetation. The hard, hollow tail tip produces a warning sound like that of a rattlesnake.

Right: The markings on the bush­master's skin enable it to blend in with dead foliage.

~ BREEDI NG The normally solitary bushmas­ter relies on a powerful scent to track down a mate. The male snake approaches the female, stroking her chin with his head. If she responds, the two snakes entwine their bodies in an elabo­rate courtship ritual before finally mating.

The female lays about 1 0 large white eggs in a shallow hole in the ground and covers them with damp earth to keep them

Left: The bushmaster is the largest venomous snake in the Western Hemispheres.

• Deprived of its senses of sight and smell in an experi­ment, a bushmaster was still able to strike its prey. • There are only 25 recorded cases of bushmasters biting humans. Five of these bites were fatal. • According to a South Amer­ican legend, the bushmaster

at the right temperature. She coils her body around the eggs to protect them until they hatch.

After about nine weeks the young snakes break out of the eggs, using a special egg tooth that grows on the upper jaw and drops off shortly after hatch­ing. The fully developed young can fend for themselves as soon as they hatch. But they do not reach sexual maturity until they are at least two years old.

Right: The bushmaster is the only pit viper that lays eggs. Other pit vipers bear live young.

can put out fires. Different legends tell of fully grown snakes that suckled from cows and sleeping women. • The bushmaster is called "pineapple snake" because of its rough, knobby skin. • Captive bushmasters do not adapt well because they refuse to eat.

~ FOOD &: HUNTING The bushmaster feeds mainly on rodents of various sizes. It hunts at night, lying motion­less in the undergrowth wait­ing for an unsuspecting animal to pass by.

Like all pit vipers, the bushmas­ter has two pit organs located between the nostrils and the eyes. It is thought that these organs act as sensory devices, responding to the heat given off by other animals. The bush­master uses its pit organs to de­tect prey. Once it has located its victim, the snake can strike. It sinks its long, tubular fangs into

Left: The bush­master has two special pit or­gans that can sense the body heat of other animals. With these organs and its sensitive eyes, the bush­master can de­tect prey from a distance of 20 inches.

the animal's body and injects a large quantity of venom into its bloodstream. This venom at­tacks the blood vessels, causing a massive heart attack.

With its specially hinged jaws, the bushmaster can open its mouth wide enough to swallow prey whole. The muscles of the esophagus (throat) slowly move the dead animal into the bush­master's body, and powerful juices in the stomach immedi­ately begin to digest the prey. The bones and hair are either digested or passed out in the feces later.

"" CARD 35 SPECTACLED CAIMAN ,, _______________________ G_R_O_U_P_3_:_R_EP_T_ll_E_S_& __ A_M_P_H_IB_IA __ N_S _~~ ... ORDER FAMILY GENUS & SPECIES

"IIIIIIII Crocodilia Alligatoridae Caiman crocodilus

A relative of the alligator, the spectacled caiman is found throughout Central and South America. Its name refers to the

bony ridges above its eyes and snout that look like a pair of glasses.

KEY FACTS

SIZES

Length: Up to 8 ft. Weight: Up to about 65 lb .

BREEDING

Sexual maturity: Usually by 8

years of age. Females have been

known to breed at 4 years.

Breeding season: Beginning of

rainy season; usually April to June,

but varies with location.

No. of eggs: 25-30.

Incubation period: 4-8 weeks.

LIFESTYLE

Habit: Generally solitary; aquatic.

Diet: Mainly fish, crustaceans, and

mollusks.

Lifespan: Possibly to 60 years.

RELATED SPECIES

There are 4 other caimans: the

black caiman, broad-snouted

caiman, smooth-fronted caiman,

and dwarf caiman. All of them live

in the American tropics.

Range of the spectacled caiman.

DISTRIBUTION

Native to Central and South America, from Mexico in the

north to Paraguay in the south. Also found on some southern

Caribbean islands, including Trinidad.

CONSERVATION

The spectacled caiman's ability to survive in a wide variety of

habitats has enabled it to remain fairly numerous, despite its

being widely hunted.

THE SPECTACLED CAIMAN'S NEST Nest building and maintenance: After mating, the female spectacled caiman builds a nest close to the water's edge. First she scrapes up a pile of vegetation that may measu re 11f feet high by 3 feet wide. Then she crawls on top of the pile and presses it down with the weight of her body in order to shape the nest. Next she digs a hole in which she lays her eggs. Finally she covers the eggs with vegetation to help them incubate.

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nearby to keep away intruders.

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Broad-snouted caiman: Grows up to 8 feet long and has a distinctive wide snout.

Dwarf caiman: One of the small­est caimans, reaching only 5

, feet in length .

01 60200491 PACKET 49

The spectacled caiman lives in a vast region

that stretches from Mexico in the north to Paraguay

in the south. Throughout this range four subspecies,

or races, occupy separate geographical areas.

They are the common spectacled caiman, the

brown caiman, the Apaporis River caiman

and the Paraguay caiman or jacare.

~ HABITAT The four subspecies of specta­cled caiman differ slightly in appearance and habit. The common spectacled caiman has been studied most widely. It is found in Venezuela, Co­lombia, Ecuador, Guiana, and the Amazon regions of Bra­zil, and on Trinidad and a few other Caribbean islands.

The common spectacled cai­man lives in fresh water and prefers ponds and lakes to riv­ers. All races frequent marshes and swamps except the Apa­poris River caiman, which lives only in the upper reaches of its namesake river in Colombia.

DID YOU KNOW? • The spectacled caiman was originally named Lacerta croc­odilus by the great taxonomist Linnaeus. So it became known as Caiman crocodilus when the genus Caiman was accepted. But since caimans are more closely related to alligators, some experts feel this name

~ FOOD & HUNTING The spectacled caiman preys on a wide variety of fish and invertebrates, including water snails and crabs. Because it is a cold-blooded reptile, the spec­tacled caiman does not need to consume as much food as a warm-blooded animal of equal size. As a result, it can afford to be an opportunistic hunter, snapping up whatever prey comes within reach of its jaws. Such prey may include mam­mals and carrion (dead animals).

Right: The spectacled caiman will snap up anything in its path.

is misleading. They prefer to use the second-oldest name, Caiman sclerops.

• The baby "alligators" that are often sold to tourists in North America are, more often than not, young specta­cled caimans that have been imported from Colombia.

Top left: The cold-blooded spectacled caiman likes to bask in the sun.

Left: A young spectacled caiman. Some youngsters stay close to their parents for 18 months before going offon their own.

Right: The spectacled caiman be­comes sexually matureata certain size, not age.

~ SPECTACLED CAIMAN & MAN Large anaconda snakes and jaguars occasionally prey on spectacled caimans. But hu­mans are the caiman's main enemy. Many of these reptiles are shot by cattle ranchers who mistakenly think they are a threat to livestock. But the majority fall victim to hunters who capture them for the pet

~ BREEDING The spectacled caiman is usu­ally mature by its eighth year. In breeding season, the gen­erally solitary adults seek each other out and then mate in shallow water.

The spectacled caiman usually hides its nest beneath a bush or shady cypress so the eggs will

trade and for sale to tourists. Because alligators are legally protected, the spectacled cai­man is now the most popular and widely kept crocodilian. The large-eyed young are ap­pealing, but they do not make good pets. Their specialized needs make them unsuitable for homes.

be protected from the sun. The female digs a cavity in the nest, where she deposits up to 30 eggs. The white eggs are about two to three inches long and up to one and a half inches wide. Once the clutch is complete, the female covers it with vege­tation. The tropical heat and de­caying plant matter provide warmth for incubation.

When the young reptiles hatch, they are 6 to 1 0 inches long, and their yellowish bodies are marked with black bands. It is not long before they must fend for themselves, and many fall victim to predators.

'" CARD 36

MARSUPIAL FROG "~ _____________________ G_R_O_U_P __ 3:_R_E_PT_I_lE_S_& __ A_M_P_H_IB_I_A_N_S _"~

.. CLASS ~ Amphibia

.. ORDER ~ Anura

.. FAMILY ~ Hylidae

.. GENUS ~ Gastrotheca

Marsupial frogs are named for marsupial mammals such as the kangaroo. Like these mammals, they carry their young in a pouch

to protect them until they are able to survive on their own.

KEY FACTS

SIZE

Length: 1-4 in .

BREEDING

Mating: Throughout the rainy sea­

son. Females come to calling males

when they are ready to release

their eggs.

No. of eggs: 4-200, increasing

with size of species.

Development: Tadpoles usually re­

leased after 3-4 months.

LIFESTYLE

Habit: Generally solitary; active at

night. Range of marsupial frogs.

DISTRIBUTION Diet: Tadpoles eat algae from rocks

and plants. Adults eat insects and

similar small animals.

RELATED SPECIES

Found in Central and South America, from lowland rainforests

to plateaus in the Andes over 13,000 feet above sea level.

CONSERVATION There are 39 Gastrotheca species

and 21 very similar species in 6

other genera. All belong to the

true tree frog family, Hylidae, which has 637 species through­

out the world.

Several species of tropical frogs have disappeared in recent

years for no obvious reason . Marsupial frogs remain fairly com­

mon, but many may be threatened by the destruction of their

rainforest habitat.

FEATURES OF MARSUPIAL FROGS

Dorsal pouch: Present only on females. Outside the breeding season, the pouch looks like a small slit on the frog's back. As fertilized eggs develop inside the pouch, it stretches to ac­commodate them. This makes the frog look swollen.

Birth of young: When the young are developed enough, the fe­male opens her pouch and re­leases them. If she is "giving birth" to tad­poles, she posi­tions herself carefully so that they fall into a pool of water.

Coloration: Varies greatly among species. Most have green or-brown

markings that'provide camouflage In their

tropical forest habitat.

© MCMXCII IMP BV/IMP INC WILDLIFE FACT FILETM PRINTED IN U.S.A.

loses water. The , frogs must stay

in damp, shady places where the

skin will not dry out.

Have long toes with suc­

, tion disks that help the frogs

grip leaves and branches.

0160200601 PACKET 60

Female marsupial frogs are model parents.

They produce relatively few eggs and keep them in

a pouch. After the eggs hatch/ the young may develop

further inside the pouch/ which increases their chances

of survival. Most other frogs/ by contrast/ produce huge

numbers of eggs to compensate for the fact that most

will die or be eaten before reaching maturity.

~ HABITS Marsupial frogs live in the trop­ical forests of South and Cen­tral America. They spend their

lives in the trees foraging for food and rarely descend to the

ground. Their long toes have suction disks that give them a

powerful grip, so they can leap and climb with ease.

Marsupial frogs are active

mostly at night. As amphibians, they risk deadly dehydration if they are exposed to the sun. Be­cause amphibian skin is usually not waterproof like the skin of

reptiles and mammals, frogs are able to soak up water when they need it. But their skin also lets

water in their bodies evaporate.

Marsupial frogs, like most tree­

dwelling frogs, do not have easy access to pools of water in which to replenish moisture. As a re­

sult, they must conserve what water they have.

By day most marsupial frogs lie in a damp, dark spot. They are concealed from enemies by

the shade and by their green and brown coloring. In several species this camouflage is en­hanced by fleshy "horns" that

break up the frog's outline and make it less likely to be recog­nized for what it is.

Right: After releasing the young from her pouch, a female leaves them to fend for themselves.

~ FOOD &: FEEDING Marsupial frogs feed mainly on insects. Some species are agile hunters, leaping up and snatch­ing flies from the air. But most species hunt insects that rest

on leaves or twigs. As long as an insect stays still,

it is safe. But the tiniest move­ment catches the frog's atten­tion. For a few moments the

frog studies its prey and moves closer. If the insect does not

Left: With her pouch full of devel­oping young, this female marsu­pial frog appears swollen.

DID YOU KNOW? • Marsupial frogs have a patch of very thin skin on their bel­lies. They use this skin like a

sponge to soak up moisture from damp leaves.

• Gastrotheca, marsupial frogs' genus name, means "stomach pouch." The frogs were given this name when they were first

discovered, and the purpose

move again, the frog may lose interest. But if the insect moves

again even just a little, the frog opens its mouth and its victim

is gone, snatched in a flick of the frog's long tongue.

To swallow its meal, the frog performs an unusual maneu­ver-it forces food down its

throat by retracting its eyeballs down to the roof of its mouth to create needed pressure.

Right: In some species the young marsupial frogs do not emerge until they are fully developed.

of the pouch was not clear.

• Some tree frog species have a different way of protecting their offspring. The poison­arrow frog carries its tadpoles

to a specially built nursery pool to develop in safety.

• In some marsupial frog spe­cies, the female's pouch holds

200 eggs.

~ BREEDING Rather than laying large num­

bers of eggs and abandoning them, marsupial frogs care for their young until they have

developed enough to survive. The female has a pouch on her back that serves as an incuba­

tor and nursery. The pouch has an opening near the female's

egg duct. As she lays her eggs, they are fertilized by a male that is clinging to her back. He then stuffs the eggs into the pouch with his hind feet.

The eggs develop and hatch inside the pouch. In some spe­

cies, the young develop in the pouch into tiny, fully formed frogs. Since the young are not

Left: A male marsupial frog has a big vo­cal sac, and he calls every night until he attracts a mate. After mating, he leaves the female, who cares for the young alone.

released as tadpoles, the par­

ents do not need to go near water in order to reproduce.

In other species, the young are ejected from the female's

pouch after a period of three to four months, while they are still tadpoles. The female finds a pool for them, either on the

ground or in a bromeliad-a plant that grows high in the trees and traps moisture in

its vaselike foliage. Using the long toes of her hind feet, she opens the pouch and scoops the tadpoles into the water.

There they change into tiny frogs and climb out to begin life in the trees.

"'CARD 37 GAVIAL "~ _____________________ G __ RO_U_P __ 3:_R_E_PT_I_l _ES_& __ A_M_P_H_IB_1_A_N_S_~~ ... CLASS

'11IIIIIIII Reptilia ORDER Crocody/ia

... FAMILY '11IIIIIIII Cavia/idae

GENUS &: SPECIES Cavia/is gangeticus

The gavial of India is one of the largest and strangest crocodiles. With its slender, sharp-toothed jaws, it is well equipped

to feed almost exclusively on fish.

KEY FACTS

SIZES

Length: Male, up to 21 ft., possi­

bly longer. Female, up to 13ft .

Weight: Up to 2,200 lb.

BREEDING

Sexual maturity: 10 years.

Breeding season: From late winter

to spring.

No. of eggs: Average, 40; but up

to 97 recorded in 1 clutch.

Incubation: 2-3 months.

LIFESTYLE

Habit: Usually solitary or lives in

small groups.

Diet: Mainly fish; also some water

birds, crabs, and small mammals.

Range of the gavial .

DISTRIBUTION

RELATED SPECIES

The gavial is classified in a family

of its own. But the false gavial,

Tomistoma sch/ege/i, is grouped

among the true crocodiles in the

family Crocodi/idae.

Found in the Indus River system in Pakistan and western

India. A larger eastern population occurs in the rivers Ma­

hanadi, Ganges, Brahmaputra, Kaladan, and Irawaddy.

CONSERVATION

The gavial is recovering from a serious decline, thanks to a

concerted conservation and captive breeding program. But

it is still listed as endangered.

FEATURES OF THE GAVIAL HOW THE GAVIAL FEEDS

Hide: Very tough and protective. Highly prized by hunters for the skin trade, although the gavial now re­ceives some legal protection.

suit the gavial's aquatic life. Female uses them to dig a nest and to manipulate her eggs.

Movement: Unlike most crocodiles, the gavial cannot raise its massive body and tail off the ground to walk. Instead, it drags itself slowly forward .

Snout tip: A protruding lump of tissue develops on the mature male. Its pre­cise function is unknown. It may be used to amplify the calls uttered by the male in the breeding season.

Snout: Very narrow for a crocodilian. More than 100

teeth intermesh when the jaws are cl.osed. The gavial has no lips to keep

out water. But like all crocodiles it can breathe through its nostrils while its mouth is full of water.

© MCMXCII IMP BV/IMP INC WILDLIFE FACT FILETM PRINTED IN U.S.A.

The snout is ideal for a swift un­derwater attack. Presenting little resistance to the water, it can be flicked to one side to slice into fish or snap shut to trap them.

0160200651 PACKET 65

The gavial has long been hunted for its smooth, durable

hide, which can be polished to a lustrous finish. Because

the remaining population has lost much of its freshwater

habitat to intensive rural development, sanctuaries have

been established in an attempt to save this endangered

species. But even though there are widespread captive

breeding programs, the gavial faces an uncertain future.

~ HABITS The gavial basks on sandbanks

but rarely goes far from water. It

prefers clear, fast-moving rivers

with an occasional deep pool

where it can lie half-submerged,

with only its eyes and nostrils

above the surface.

Reptiles depend on external

warmth to maintain their body

temperature. Water is often the

warmest place to be because

Right: With more than a hundred teeth in its slender jaws, the ga­vial is well equipped to trap fish.

water temperature is more sta­

ble than air temperature. Since

the gavial lives farther north

than most crocodilians, it often

spends winter nights in the wa­

ter. It sinks to the bottom, where

the water is warmest. Its body

processes slow down, so it needs

little oxygen. If it has to breathe,

it surfaces for air but soon re­

turns to the warm depths.

~ FOOD &: HUNTING Most crocodilians grab any food

that comes their way. But the

gavial is a specialist that preys

almost exclusively on fish. It lies

in ambush and snatches them

in its slender, elongated jaws.

After seizing its victim, the ga­

vial surfaces to juggle the fish

around so it can be swallowed

headfirst. Sometimes it thrashes

the fish in the water to break it

up. Because it is cold-blooded,

left: The gavial spends most of the day basking in the sun to warm its massive body.

DID YOU KNOW? • Crocodiles swallow pebbles

to grind up food in their stom­

achs. Gavials that have been

the gavial needs little food ener­

gy. One bellyful lasts for a week.

A large gavial also takes water

birds and small mammals if it

can catch them, but it is virtual­

ly harmless to humans. Gavials

from the sacred Ganges River

have been found with human

remains in their stomachs. But

it is almost certain that they fed

on corpses floating down the

river in Hindu funeral rites.

Right: The gavial tosses fish head­first down its throat to avoid chok­ing on the gills.

on catfish, which in turn prey

on tilapia fish caught by local

fishermen. The decline of the

found with anklets and brace- gavial has caused a popula-

lets in their stomachs proba- tion explosion among catfish,

bly swallowed them for the which have eaten most of the

same purpose, getting the tilapias. So the more catfish-

jewelry from human remains eating gavials there are, the

in the Ganges River. more tilapias there will be for

L • The gavial preys primarily __ I_ndian fishermen. _

~ GAVIAL &: MAN The gavial has been widely killed

for its skin. In addition, it has lost

much of its habitat as rivers have

been dammed to provide elec­

tricity and irrigation to drought­

prone rural India.

By 1975 fewer than 70 gavials

lived in the wild, and the Indian

government set up a breeding

program. Eggs were taken and

~ BREEDING In late winter or spring, the male

gavial tries to gather a harem of

three or four females. He attracts

them with whistles and hisses,

then mates with each female in

the water. When mating, the

pair sinks to the bottom with

bodies entwined.

Like all crocodilians, the female

gavial lays eggs. She digs a small,

shallow hole some 30 feet from

the river and deposits about 40

brittle-shelled eggs in the nest.

She chooses the site with care

to ensure the best possible con­

ditions for incubation. The fe-

left: Each hatchling opens its shell with an egg tooth, then croaks to attract its mother.

young gavials reared to a length

of about four feet before being

released. At that size gavials can

usually look after themselves.

Today, the wild population is

about 2,000, but most of the

animals are too young to breed.

With fewer than 20 sexually ma­

ture males now in circulation,

the species is still in danger.

male stays near the nest, often

lurking in the water nearby, and

chases off egg thieves such as

monitor lizards and jackals.

The warmer the weather, the

sooner the eggs hatch. After

two to three months, the hatch­

lings emerge. Their mother digs

the nest open and guides the

tiny gavials to the safety of the

water. She often carries them in

her mouth, with their tiny legs

protruding between her teeth.

Despite this maternal care,

many of the young die. They

are snatched by predators or

swept away to drown in the

seasonal floods. Of the whole

clutch, only one may survive.

COMMON TOAD

"''--------.... CLASS ORDER '11IIIIIIII Amphibia Safientia

CARD 38~

GROUP 3: REPTILES & AMPHIBIANS FAMILY Bufonidae

GENUS & SPECIES Bufo bufo

Many people fear the common toad because of its appearance and poisonous skin. But this shy and docile amphibian is usually

harmless to humans, and it may even be a help to gardeners.

KEY FACTS

SIZES

Length: Male, 3 in. Female, 5 in.

Weight: Male, ~-2 oz. Female,

)4-40z.

BREEDING

Sexual maturity: Male, 4-5 years.

Female, 3-4 years.

Mating: February to April.

No. of eggs: 3,000-12,000 (2 or 3

larvae survive to adulthood).

Larva to adult: About 12 weeks.

LIFESTYLE

Habit: Mainly solitary.

Diet: Various invertebrates. Range of the common toad.

DISTRIBUTION Call: Male emits a rapid, high­

pitched sound when alarmed and

a slower, longer croak during the

mating season.

Lifespan: 30-40 years.

Found in most of Europe, but not in Ireland, Corsica, Sardinia,

or the Balearic Islands. Also found in northwestern Africa and

temperate Asia as far east as Japan.

RELATED SPECIES CONSERVATION The 227 known species in the fam­

ily Bufonidae include the American

toad, Bufo americanus, and Wood­

house's toad, B. woodhousei.

Although the common toad is widespread, its habitat, like that

of all aquatic and semiaquatic species, is threatened by indus­

trial pollution and the urbanization of rural areas.

FEATURES OF THE COMMON TOAD

Coloration: A mottled skin in shades of yellow and brown provides the toad with excellent camouflage in much of its natural habitat.

Poison: To deter predators, two kinds of venom are secreted from glands on the back and chest.

Eyes: A transparent pro­tective "third eyelid," called the nictitating membrane, allows the toad to see underwater.

Tongue: Up to 4 inches long, pink, and

sticky. A hinge at the front of the mouth allows the toad to flick it in and out with amazing speed. It is activated by a reflex mechanism.

Limbs: Forelimbs are used to grasp prey and enable the

male to clasp the female when mating. Forefeet are

not webbed. The larger, more powerful hind

limbs propel the toad forward.

I

I

o r--f­w ~ o it o r-­o

~ ;; o co 0... (f) ::J

:;;

ill .-1 u::: f­o Lf: w LL ::J o .-1

~ o ~ 0... 2 ;; co 0...

~ :; o X 2 o 2 @

In emergencies the common toad defends itself with a thick,

white poison. Secreted by glands surrounding the "warts" on

the toad's back, this poison works by paralysis. Although

enough venom can be produced to kill a dog, it is so sour

that it repels most dogs after a single sniff. Other predators

such as grass snakes, owls, or crows are not greatly affected

by the toad's venom, so they continue to attack the animal.

~ HABITS The common toad spends the summer alone but often hiber­nates with other toads. Although less active when hibernating, it does not actually sleep. It stops feeding and lives off fat stored in its body. It does not eat again until it mates in spring.

If alarmed, the toad can pro­duce two kinds of poison from glands on both its back and chest. One poison is colorless and smells like mushrooms and vanilla . It has a numbing effect.

Right: If threatened, the common toad puffs up its body to display its venomous, warty skin.

The other thick, white venom is secreted only in emergencies.

The common toad is agile and has a good sense of direction. It climbs walls and trellises and can leap up to six inches.

~ FOOD Est HUNTING The adult common toad feeds on invertebrates such as spiders, ants, earthworms, slugs, cater­pillars, beetles, and bees. It can handle poisonous prey, and it readily eats young frogs, newts, and lizards.

The toad hunts primarily at night. It can swim well and walk fast but is generally sedentary. It may move slowly, looking for signs of prey, but much of the time it sits and waits. When the toad sees prey, a reflex mecha-

Left: After it becomes an adult, the common toad leaves the pond but returns each year to breed.

I DID YOU KNOW? • The common toad can live underground for three years without food. It loses weight and survives on very little air. • The Greek philosopher Aris­totle gave one of the first de­scriptions of the toad's pale pink tongue. • In medieval times, people thought the toad had the evil

nism activates its tongue. The sticky tongue flicks out, attaches itself to the prey, and returns in a split second. Because the toad lacks teeth, it crushes the prey against the roof of its mouth. It then swallows by retracting its eyeballs deep into its head to push the food down.

Toads compete for their food by shoving each other out of the way. They rarely attack one another but may eat the young of their own species.

Right: The common toad feeds heavily on earthworms and other invertebrates after breeding.

eye and could cast spells. It l was suspected of turning wine to vinegar and suckling milk from cows. Some believed there was a magical golden stone in the toad's head. • The English dish "toad-in­the-hole" was named for the toad's habit of hiding under the ground.

I 1- :,d NATUREWATCH The common toad breeds in water but lives most of its life in woods, fields, gardens, or sheds. Active mainly at night, it chooses a dark den in a tree stump, under stones, beneath thick plants, or in a hole in the ground.

~ BREEDING After hibernation, the adult male common toad heads for the nearest pond. Attracted by his nightly croaking, the female arrives up to two weeks later and is seized by the male. Using the swollen "nuptial pads" on his thumbs, he grips her around the stomach. Only one male can mate with a female. Others try to dislodge him, and the competition lasts for days.

The female lays two strings of jelly-covered eggs, which the

Left: Clasping the female, the male fertilizes the strings of jelly-covered eggs she releases into the water.

In October the toad hiber­nates in a deeper shelter. It may use its hind legs to dig a hole in sandy soil or to bury itself in a manure heap. In early February it heads for ponds to breed, then returns to its solitary life in summer.

male then fertilizes in the water. Spawning takes 10 to 28 hours. Parents do not tend the young .

Over the next 20 days, the offspring grows from an eye­less organism that cannot eat into a tadpole with a long tail, eyes, a mouth, and two rows of teeth. It eats plant matter and breathes through feathery gills. Four limbs gradually emerge, and the tadpole reabsorbs its tail, loses its teeth, and forms a membrane over its gills. It becomes a tiny toad, able to breathe internally, crouch, walk, and swim.

'" CARD 39.-J SKINK ,, ____________ G_ RO_ U_P_3: REPTILES & AMPHIBIANS ... CLASS ... ORDER ,. FAMILY

~ Reptilia ~ Squamata ~ Scincidae

Skinks are an extremely varied group of lizards. These reptiles have developed such a wide range of adaptations that it is hard to

believe they all belong to the same family.

KEY FACTS

SIZE

Body length: 1-24 in ., depending

on the species .

BREEDING

Method: Some skinks bear live

young; others lay eggs.

No. of young: Usually 1-25,

depending on the species. Maxi­

mum on record, 67.

LIFESTYLE

Habit: Burrowing, tree-climbing,

or ground-dwelling. Mostly active

by day.

Diet: Small species eat inverte­

brates; large species usually eat

plants.

RELATED SPECI ES

There are over 1,200 species of

skink worldwide, grouped in 85

genera. Their closest relatives are

spiny girdle-tailed lizards, family

Cordylidae, such as the sungazer,

Cordylus giganteus, of Africa.

DEFENSES OF SKINKS

Blue-tongued skink: Uses shock tactics for defense. When threatened, it opens its mouth and sticks out a startling bright blue tongue, often hissing menacingly at the same time.

©MCMXCIV IMP BV/IMP INC WILDLIFE FACT FILETM

Range of skinks.

DISTRIBUTION

Skinks are found in a wide variety of habitats in tropical and

temperate regions throughout the world. The majority of

species inhabit Southeast Asia and Australasia.

CONSERVATION

The majority of skinks are in no immediate danger, although

at least four species are classified as rare.

American five-lined skink: If attacked, it wriggles its bright blue tail conspicuously

while keeping the rest of its body still. If the predator seizes the tail, the

skink casts it off and retreats

Stump-tailed skink: Deters attackers with its bright blue tongue. Also has a fat tail that serves as a decoy. Predators are fooled into attacking this tough stump instead of the more vulnerable head.

PRINTED IN U.S.A. us P 6001 12 068 PACKET 68

Left: The giant Solomon Island skink can grow to two feet long. Its strong limbs and claws are perfect for life in the trees.

Skinks are the most numerous, widespread lizards in the

world. They live in all kinds of tropical and temperate

habita~from rainforests to deserts and grassy plains to

rocky mountains. Skinks have evolved a wide variety of

features to suit their environments. Some are blind, legless

burrowers, while others are powerful climbers and swimmers.

~ CHARACTERISTICS Skinks have a wide range of fea-tures. But most skinks are small and short-legged with smooth, shiny brown scales and long, slender tails.

Like most lizards, a skink usu­ally walks by moving diagonally opposite legs and wriggling its body in a snakelike motion at each step. But some skinks have evolved differently to suit their habitats. Some species have no legs, while others have virtually useless remnants. For example,

the sandfish of Africa "swims" through the desert sand like an eel, retracting its almost useless legs into recesses in its flanks. In contrast, the green-blood skink is suited to climbing, with adhe­sive toe pads and strong legs.

The giant Solomon Island skink climbs with the aid of a muscular, prehensile (gripping) tail. The stump-tailed skink, on the other hand, has only a short tail, but it helps to protect the animal from predators.

~ BREEDING Skinks have a variety of breed­ing habits. Some species, such as the giant Solomon Island skink, give birth to one large, fully formed infant.

Other species lay clutches of up to 25 eggs. In certain spe­cies, such as the great plains skink of North America, the female incubates her eggs by

Left: Over a foot long, the stump­tail, or shingleback, inhabits dry areas of Australia.

DID YOU KNOW? • The green-blood skink is unique among vertebrates in having green blood, green scales, a green tongue, and green eggs. • Most skinks have smooth scales, which make the ani­mals very hard to catch. But

L-

curling her body around them. She also helps the young hatch by licking them clean as they emerge from their shells.

The females of other species abandon their eggs. Although they produce larger clutches than their more protective rela­tives, a large proportion of their eggs may be lost to predators.

Right: The female southeastern five-lined skink guards her eggs before and during hatching.

Left: Like the rainbow skink of southern Africa, most typical skinks feed mainly on insects and other small invertebrates.

Cunningham's skink has spiny scales with which it wedges itself into cracks. • Several burrowing skinks do not have legs or any sense of sight. They rely on vibrations and scent to detect their un­derground invertebrate prey.

~ FOOD & FEEDING Large skinks like the Solomon Is­land skink often eat plants. Small species like the sandfish eat in­sects, spiders, and millipedes.

Some species have more spe­cialized diets. The marine skink preys on small crabs and sand­hoppers on the rocky shores of

~ HABITS Most skinks are active by day. These secretive creatures spend much of their time hiding be­neath logs, among fallen leaves, or even underground. But some species live in trees. The Solo­mon Island skink, for example, spends almost all its time in the branches, rarely descending to the ground.

Like all cold-blooded animals,

Left: The Cape legless skink can burrow under the sand to escape the intense midday heat.

Left: The sand­fish possesses a streamlined head with a pointed snout for pushing through sand. Its mouth opens under the snout.

its habitat. Other shore-dwelling skinks eat scraps that seabirds drop during their breeding sea­son. This food is so abundant that the skinks can live off their energy reserves for the rest of the year, after the birds with their scraps have disappeared.

a skink needs external warmth to raise its body temperature. As a result, it usually basks in the morning sun before forag­ing for food. By noon a skink may start to overheat, so it re­treats into the shade to cool off, emerging later for anoth­er period of activity. When the temperature drops at the end of the day, a skink is forced to go back to its shelter. There it spends the night in a semidor­mant condition .

~RD40~ PARADOXICAL FROG

" .. CLASS '1IIIIIIII Amphibia

.. ORDER '1IIIIIIII Anura

GROUP 3: REPTILES & AMPHIBIANS FAMILY Pseudidae

.. GENUS & SPECIES '1IIIIIIII Pseudis paradoxa

The paradoxical frog looks normal enough, but the same cannot be said for its tadpoles. Three times the size of their parents,

these enormous babies actually shrink as they mature.

KEY FACTS ~~----------------------------------------------------~

SIZE

Length: Tadpole, up to lOin.

Adult, up to 3 in .

BREEDING

Mating: In tropical wet season.

Eggs: Laid in a mass of jelly in

the water.

LIFESTYLE Habit: Solitary outside the breed­

ing season. Diet: Adult eats insects and small

crustaceans. Tadpole eats plant

matter such as algae.

51 RELATED SPECIES

~ There are 4 species of pseudid, or

shrinking, frogs including Pseudis bolbodactyla of Brazil. The para­

doxical frog is the largest of the

family. All 4 species are related to

the true frogs, which include the

North American bullfrog, Rana catesbeiana; the green frog, R. clamatans; and the leopard frog,

R. pipiens, of North America.

Range of the paradoxical frog.

DISTRIBUTION

Found in scattered locations in eastem South America, from the

northern tip south through Amazonia to northern Argentina.

Also on the island of Trinidad, off the coast of Venezuela.

CONSERVATION

The paradoxical frog is in little immediate danger from humans

because it lives in very remote areas. Local populations are vul­

nerable to habitat loss, however.

~ATURES OF THE PARADOXICAL FROG

Adult: Only a few inches long when fully grown.

Eyes: Large and bulging. Often the only part of the frog that is visible in the water.

Fingers: Extended like the toes. An opposable thumb enables the frog to grip prey tightly.

Young (shown to scale): At10 inches long, the tadpole is 3 times the size of its parents.

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Skin: Extremely slippery, enabling the frog to escape

the grasp of predators.

Feet: Large and webbed. Each toe has an extra joint

called a phalanx that allows the frog to extend its reach .

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The paradoxical frog is seldom seen and rarely caught. It

lives in marshes and forest pools, where it hides under thick

vegetation. Only very determined zoologists have been able

to observe this elusive creature in the wild. For many years,

their observations were disputed because the facts about the

paradoxical frog were considered too strange to be true.

~ HABITS One of a number of unusual things about the paradoxical frog is its highly aquatic way of life. All frogs must stay moist in order to survive, but most species do not linger in the water. They return to land to search for prey in the damp grass or leaf debris.

By contrast, the paradoxical frog breeds, feeds, and sleeps in water, rarely leaving it. It is usually seen floating in a pool of water, with just its eyes and nostrils protruding above the surface. It prefers still waters

with thick, floating vegetation that offers plenty of cover. If the frog is alarmed, it dives be­neath the foliage and disap­pears from view.

The paradoxical frog favors the more remote swamps and marshes of Trinidad and Ama­zonia, far from human habita­tion, and its elusive habits make it hard to find. As a result, little information exists about its be­havior in the wild.

Right: The adult paradoxical frog grows very little and is dwarfed by its oversize offspring.

~ FOOD & FEEDING The adult paradoxical frog eats small water animals. Like most frogs, it has powerful hind legs with large webbed feet. Each of its long projecting toes has an extra joint called a phalanx.

These extra joints make its toes more dexterous and enable the frog to extend its reach. These toes facilitate combing through mud and flushing out insects and small crustaceans.

The frog's fingers are extended in the same way as its toes. The innermost finger acts as an op­posable thumb, so that the frog

left: The paradoxical frog is more aquatic than most frogs and rarely leaves the water.

DID YOU KNOW? • A noisy creature, the para-doxical frog is more often heard than seen. It produces coughing grunts like those of a pig. • When the paradoxical frog and its tadpoles were first described, most scientists

can capture prey in its hands. The larva, or tadpole, of the

paradoxical frog feeds only on plant matter. Like most larvae, it eats as much as possible in order to build up the energy supplies necessary for its meta­morphosis into an adult. The tadpole uses its horny teeth to scrape algae off rocks and wa­ter plants. It digests the tough plant cells in its elongated gut. The gut of the adult is propor­tionately much shorter, since its diet of animal matter is easi­er to digest.

Right: The adult paradoxical frog is only a few inches long, but it is the largest frog in its family.

assumed that they were differ­ent species. The true relation­ship between the adult frog and its young was finally proven by captive breeding. • In South America the huge tadpoles are caught and sold as delicacies in food markets.

~ BREEDING Most frogs lay their eggs in water in a mass of jelly. Small aquatic larvae, called tadpoles,

hatch from the eggs. As each tadpole develops, it exchanges its gills for lungs, grows legs, and loses its tail. By the time the tad­pole changes into a tiny frog, its body has grown only slightly. It then grows into the much big­ger adult frog.

The paradoxical frog devel­ops in much the same way, with one major exception: the main growth stage occurs when it is still a tadpole. When it hatches,

left: The para­doxical frog is well adapted for escaping from predators. It is well cam­ouflaged,and its slippery skin is very difficult to grasp.

the tadpole looks normal, but it grows at an amazing rate. A fully grown specimen may be 10 inches long-three times the size of its parents.

As it undergoes its metamor­phosis into an adult, the tadpole sprouts legs, loses its tail, and develops the features typical of all frogs-a broad mouth, bulg­ing eyes, and a short, angular body. The tadpole keeps shrink­ing day by day. By the time it becomes a recognizable frog, it is only one-third of its origi­nallength.