Published by

Friends of the National Zoo

National Zoological Park

Washington, D.C. 20009

Phones:

Executive Director-and membership:

232-7700

Education and Volunteer Offices:

232-7703

Guided tours: 232-7703

Train tours: 232-7704

Window Shop: 232-7705

FONZ Board of Directors 1973-1974

Arthur Arundel, President

Montgomery S. Bradley, First Vice President

Lavell Merritt, Second Vice President

Stephen Hosmer, Treasurer

Joan L. Jewett, Secretary

Peter C. Andrews

Theodore Babbitt

John S. Brown

Timothy V.A. Dillon

Ronald Field

Donna K. Grosvenor

Robert Mason

Isabel J. McDonnell

Shirley J}. McNair

Ruth N. Nelson

William N. Olinger

John B. Oliver

Nancy Porter

Whayne S. Quin

Gerald G. Wagner

Rosa M. Walker

Richardson White, Jr.

Executive Director

Sabin Robbins

Editor: Austin Hughes.

Photograph on p. 7 left by Pat Vosburgh,

all other photographs by Ray Faass.

Cover: The Zoo’s adult female emu (number 6f

on map); the emu is the second largest living bird.

Production by Monica Johansen.

THE ZOOGOER is published bi-monthly

and copyrighted © by Friends of the National

Zoo, c/o National Zoological Park, Washington,

D.C. 20009, second-class mailing permit

approved at Washington, D.C. Rate in the

United States $3 a year (of annual dues).

Emu Chicks

Zoo News — Mammals

Zoo News — Birds

Zoo Map

Zoo News — Reptiles and Amphibians

The Iguanid Lizards

Zoo Staff

Dr.

Mr.

Dr.

Theodore H. Reed, Director

Edward Kohn, Deputy Director

Warren J. Iliff, Assistant Director

John Perry, Assistant Director

Jaren Horsley, General Curator

Harold Egoscue, Curator (Mammals)

William Xanten, Curator (Mammals)

Guy Greenwell, Curator (Birds)

Larry Collins, Associate Curator (Mammals)

Miles Roberts, Assistant Curator (Mammals)

Michael Davenport, Assistant Curator

(Reptiles)

Clinton Gray, Veterinarian

Mitchell Bush, Veterinarian

Dr. Robert Sauer, Pathologist

Dr. John Eisenberg, Resident Scientist

Dr. Helmut Buechner, Senior Ecologist

. Devra Kleiman, Reproductive Zoologist

. Norm Melun, Architect

. Emanuel Petrella, Chief, Buildings & Grounds

For information concerning the collection call

381-7283 or 381-7284.

For general visitor information call 381-7235.

Friends

the

National

The Friends of the National Zoo is a non-profit

organization of individuals and families who

frequently visit the National Zoo and who are

interested in supporting its growth and develop-

ment, particularly in the areas of education,

conservation, and scientific research.

members of the Friends, you and your family

will be given benefits that will make your zoo-

going more enjoyable and educational.

For more information and a membership appli-

cation, please call 232-7700.

An emu egg, which weighs a pound and a half;

the shell is dark green in color and quite

rough-tex tured.

The giant flightless emu of Australia is rarely

reared successfully in captivity. Though a

number of zoos and private breeders

have obtained fertile eggs and have succeeded

in hatching them, the survival rate of the

young has generally been low. It is thus with

particular pride that the National Zoo is able

to announce that four young emus hatched

here in early April are doing well. All are

now about two-and-a-half feet tall; and at the

age of about two months the four weighed

between 14.5 and 16 pounds each.

The emu (Dromaius novaehollandiae) is the

second-largest living bird; its height of five to

six feet is exceeded only by the seven-to-eight

foot stature of the ostrich. Like the ostrich

it has abandoned flight in favor of a terrestrial

life in open country; its tiny vestigial wings

ordinarily lie concealed beneath its long,

fluffy body feathers. Able to run 30 miles an

hour, the emu has come to rely on its speed,

size, and keen eyesight to escape predation.

The emus are grouped with the cassowaries—

also large, flightless birds—in the order

Cassuariformes. The Cassuariformes and

three other orders of flightless birds—the

ostriches (Struthioniformes), the rheas of

South America (Rheiformes), and the kiwis

(Apterygiformes)—are known collectively as

ratites. Flying birds have a bone attached to

the breast bone that is known, because of its

shape, as the ‘‘keel’’; this bone supports the

greatly enlarged breast muscles necessary

for flight. The ratites lack this bone; and

their name, derived from the Latin word for

“raft,’’ refers to this ‘‘keel-less’’ condition.

Whether the four ratite orders are closely

related to one another or whether they

evecived flightlessness separately is not yet

known, but ornithologists are agreed that all

of them are descended from flying ancestors.

Whether closely related or not, the ratites

have in common certain other peculiarities

besides flightlessness. In all species, the male

alone incubates the eggs; and, either by

himself or with the help of females, he cares

for the young. In most birds the parents share

these duties, or they fall mainly to the female.

In addition, in all ratites but the kiwis each

male usually mates with more than one

female, and all of the females with which he

mates lay their eggs in his nest. A male emu—

which is smaller than the female—may mate

with four or five females, and the total

number of eggs laid in his nest may be as

high as 25. After laying, each female emu is

without further involvement in the reproductive

process. The Zoo has a single adult breeding

pair of emus (number 6 on map), but the

breeding pattern is similar with one female.

In early 1974, when the emus began to enter

breeding condition the female appeared to

vocalize more frequently than she had before.

The female emu has a large, inflatable sac in

her throat; and she uses it to produce a deep

thumping or booming call. When courtship

began the two would stand next to each other

and lower their heads close to the ground.

Then they would sway their heads from side

to side. Finally the female would sit down;

more correctly she was resting on her heels,

since birds walk on their toes and the backward

bend in the leg is not the knee but the heel.

The male would sit beside her and then maneuver

himself onto her back, taking hold of the skin

of her long neck with his beak. During

copulation he uttered low-intensity squeaking

and purring sounds. Afterwards he stood up

and ran away while the female remained sitting.

The male dug a shallow scrape in the ground as

a nest and the female began to lay. Bird House

personnel removed the first three eggs from the

nest and placed them in an incubator. Thus

it was hoped that, even if the male was less

than diligent in incubating the clutch, some

emu chicks could be hatched and raised.

These three eggs were laid one a day between

February 18th and February 20th; the egg laid

on the 19th proved infertile, but the other two

were good. After the first three eggs were re-

moved, the curator decided to allow any subse-

quent eggs to remain with the male. The

female continued to lay daily until the clutch

in the nest number eight eggs. When these

eggs were tested for fertility a month later,

only two proved to be fertile. Apparently,

while the female continued to produce eggs,

the male had lost interest in copulating with

her, and thus fertilizing the eggs, soon after

he had begun incubating. The eggs were dark

green in color, over five inches in length,

and about three inches in width. They weighed

about a pound and a half each.

In the wild the incubation period of emu eggs

can vary greatly—between 25 and 60 days

according to one account. The male must

leave the eggs from time to time in search of

food and water; and—depending on the success

of each of his foraging expeditions—he may

spend varying amounts of time off the nest.

Under the more controlled conditions of an

artificial incubator, there is greater uniformity.

The eggs placed in the incubator on February

18th and 20th both hatched on April 5th, for

incubation periods of 44 and 42 days

respectively. When the eggs that the male

himself incubated were tested for fertility, the

two fertile eggs were also placed in the

incubator for hatching; they hatched on April

6th and April 7th. The incubation period

could not be measured in these cases, since it

was not known when the eggs were laid.

These two eggs were removed because it was

believed that the young would stand a much

greater chance of survival if hand-raised than

they would if they remained with the father.

In the wild a male emu teaches his offspring to

feed by example. The chicks can walk within

24 hours after hatching and instinctively follow

the male from the nest. As he captures

insects on which to feed, the chicks begin to

peck at them and capture them too. But in

a zoo enclosure not enough insects would be

available, and the same type of learning by

imitation would probably not be effective

with the adults’ pelleted feed. Moreover, the

pellets in which this commercially produced

feed is packaged would have been too large

for newly hatched emus. When young emus

are hand-reared, on the other hand, patient

keepers can use a number of strategems to

induce the chicks to feed.

Recently hatched chicks of the Burmese red

junglefowl (Ga//us gal/lus)—the species ancestral

to the domestic chicken—were placed with the

emu hatchlings in the hope that feeding by the

junglefowl would be imitated by the emus.

Also a special starter feed was prepared. First

the commercial ratite pellets fed the Zoo’s

adult emus were ground up. Then a soft,

meat based commercial bird-of-prey diet and

the ground ratite diet were rolled into little

balls. The bird-of-prey diet was more important

in holding the feed together in a form in which

it would be readily pecked at and eaten than

for any dietary value of its own.

For three days Bird House personnel spent hour

after hour throwing the balls of feed into the

emu and junglefowl chicks’ pen. Young

junglefowl have a strong innate tendency to

peck at any small moving object. In the wild

this instinct leads them to peck at insects

stirred up by the mother; and, since the mother

often takes seeds or other food items and drops

them before the chick, the same instinct leads

them to peck at these food offerings. Thus

the chicks gradually learn, presumably by

associating taste with appearance, which

small objects are acceptable as food. When the

An emu chick’s powerful feet, well adapted for a

terrestrial life.

balls of feed were thrown into the pen, the

junglefowl chicks would peck at them and

soon learned to eat them. Finally the emu

chicks, whose instinct to peck at potential food

items appears to be less strong than that of

the junglefowl, began to imitate the junglefowl

and take the feed. After they had learned to

accept it, they were gradually switched toa

straight ration of ground ratite diet.

The four chicks were weighed daily for about

the first two weeks of life. Their weights

varied between 13 and 16 ounces on April

9th; by April 25th, their weights varied

between 2.5 and 3.3 pounds. Thus, over this

period there was an average gain of about

one ounce per chick per day. For the next

month, weights were taken about once every

two days; and by May 29th the chicks’

weights varied between 11.7 and 12.8 pounds.

Over this period there was an average gain of

over four ounces per chick per day. These

detailed weight records will provide an

invaluable reference in the future. This year’s

four healthy young emus will provide a

Left: an emu chick in its first brown-and-buff-

striped plumage at the age of about three weeks.

Right: in the second, gray plumage at the age

of two-and-a-half months.

standard for other emu chicks, so that their

keepers will be able to measure their progress

and detect any deficiencies early, before

serious symptoms appear.

The emu chick’s first plumage was dark brown

striped with pale buff. Like the striped and

mottled plumages and coats of many young

birds and mammals, this plumage presumably

functions as camouflage in the mixed light

and shadow of thick grass or other short

vegetation. Now, although still faintly striped,

the chicks’ basic coloration is close to the grey

of the adults. Currently the four young emus

are located in a yard behind the Zoo’s pheasant,

crane, and ratite line (number 6 on map); they

are visible, however, from the Friends of the

National Zoo Safari Train. Later, if suitable

space becomes available, they may be moved

to a yard from which they can be seen by

visitors on foot.

There was once another species of emus, the

black emu, found only on two islands off

the southwest coast of Australia; but soon

after the arrival of Europeans, the black emu

was driven to extinction. The surviving emu

species, though exterminated on the island

of Tasmania and vast portions of Australia,

is not at present in danger of extinction. How-

ever, as with much of Australia’s unique

wildlife, there is cause for concern. Emus have

been accused of drinking the water and eating

the grass needed by sheep and cattle in arid

parts of Australia, of stamping down wheat-

fields, and of eating wheat and other grain crops.

Little recognition has been given to the fact

that emus destroy large numbers of insects

harmful to crops. Recently a campaign was

begun in the huge and sparsely settled state of

western Australia to exterminate all emus

except for those living in a small protected

area in the southernmost tip of the state. In

a more humane effort at control, a fence many

hundreds of miles long was built to keep emus

away from wheat and sheep farming regions

in West Australia. In view of the apparent

unwillingness of man to coexist with emus in

much of their native land, the success that our

National Zoo and some other zoos have recently

had in breeding and rearing emus in captivity

is heartening.

realized that she was keeping it meticulously

clean for her infant. This infant—or “‘joey”’ as

the young of tree kangaroos and other kanga-

roos are known—is the first to be born since the

popular tree kangaroo group moved from their

former home in the old Lion House. Its paw

was first seen out of the pouch on May 3rd,

and its head and upper half of its body were

emerging regularly in mid-June. By the end

of June the joey began to leave the pouch

briefly.

The tree kangaroo joey, like the young of

Tree Kangaroo Joey other marsupials, is born in an extremely

undeveloped state. It weighs only a fraction

of an ounce and is blind, deaf, and hairless. The

Visitors who have seen the short, sparsely furred only features that show any great development

tail of the Zoo’s latest born Matschie’s tree are the forearms and the sense of smell, and

kangaroo curling from the opening of its on these the newborn tree kangaroo must rely

mother’s pouch may have wondered what they to make its way directly after birth from the

were seeing. They may also have seen the vaginal opening to the mother’s pouch. It

mother perched behind a rafter in the tree makes the journey without aid from the

kangaroos’ new Reptile House enclosure mother, climbing through her fur by means

(number 19 on map) carefully grooming the of its powerful forearms and guided by its

inside of her pouch with her tongue and not sense of smell alone. When the infant reaches

Matschie’s tree kangaroo with an infant in the pouch; the young

female at right is showing interest in the most recent addition to

the Zoo’s tree kangaroo society.

the pouch, it takes hold of one of the four

teats there with its mouth and remains

attached for several months. The gestation

period in all marsupials is short compared to

that of placental mammals—only about 32

days in Matschie’s tree kangaroo. Most

development takes place in the protection

of the pouch.

Matschie’s tree kangaroo (Dendrolagus

matschiei) is native to the Huon peninsula in

eastern New Guinea. It is one of five species

of tree kangaroo found on New Guinea and

in northern Australia. All are relatives of

the familiar terrestrial kangaroos that. have

adapted to an arboreal life in tropical forests.

Both arboreal and terrestrial kangaroos

comprise the family Macropodidae; the name,

meaning ‘‘big-footed;”’ accurately describes

their most striking anatomical characteristic,

the greatly enlarged hind feet. The terrestrial

kangaroos, as is well known, use their powerful

hind feet in long overland leaps. The feet of

the tree kangaroos are smaller relative to

body size than those of other kangaroos

and are equipped with rough-skinned cushion-

like soles to prevent slipping from branches.

They are used in rather clumsy short hops

along vertical branches and along the ground.

But they also function to propel the tree

kangaroo in its great leaps—up to 30 feet—

from branch to branch. The terrestrial

kangaroos use the tail as a prop or “third leg”’

to support the animal while at rest; by contrast,

the tree kangaroo’s tail, since it hangs straight

down below the branch during climbing,

lowers the animal’s center of gravity and thus

steadies it. It also performs a rudder-like

function during the tree kangaroo’s leaps.

Matschie’s tree kangaroo is a social species,

living in groups that consist—like the Zoo’s

tree kangaroo group—of a single fully adult

male, several adult females, and their offspring.

As with one juvenile male in the Zoo’s group,

younger males are tolerated by the dominant

male. Most members of this small society

show great interest when one of their number

has a joey in the pouch and may open the

pouch to inspect the infant by scent or to

groom it.

New Rodent Exhibits

More than half of the mammals now living are

rodents. The number of species included in

the rodent order is more than are found in all

other mammalian orders combined; and al-

though there is no way of reliably estimating the

number of individuals in so vast an assemblage,

it is believed likely that here too the rodents

exceed all other orders combined. There are

rodents on virtually every land surface where

mammals are able to live; and there are few

habitats—with the notable exceptions of the

airways and the oceans—that they have not

adapted to occupy. Yet, in spite of their near

omnipresence and their staggering numbers,

rodents differ remarkably little from one

another in basic structure.

All rodents are primarily vegetable feeders,

with incisors adapted for gnawing. There are

two upper incisors and two lower incisors in

every species; and to compensate for wear, the

incisors grow throughout life. Growth takes

place at the base, and the tooth is continuously

being pushed out of the jaw in the form of an

arc of a true circle. The outer surface of the

tooth is harder than the inner surface, so that

the two are worn down at slightly different

rates. Thus the tooth is to some extent self-

sharpening.

Two new exhibits at the Small Mammal House

(number 15 on map) show examples of some

of the world’s many rodent species. In one

(cage #47) are one male and three female degus

(Octodon degus) and in the other (in the

nocturnal room) are two male naked-tailed tree-

rats or climbing rats (Ty/omys nudicaudatus).

Both are South American species and at first

glance both may look a bit like common rats.

A closer look, however, will show obvious

differences. The degu’s tail, unlike a rat’s, is

covered with fur that forms a tuft at the tip;

and its head resembles a guinea pig’s more

than arat’s. The climbing rat has large hands

and feet with rounded pads on the digits—an

adaptation for climbing. The degu differs

markedly from this arboreal rodent in habits; it

is a burrowing species that lives in large colonies.

The house mice and common rats—those

persistant rodent pests and camp-followers of

man—are of Old World origin. In the New World

there is a quite distinct group of native rats

and mice, and the naked-tailed tree-rat is one

of the many species that comprise it. The degu

belongs to another characteristically New World

group of rodents—the caviomorphs. This group

includes the familiar domestic guinea pig and

such sizable rodents as the paca, Cuniculus paca,

which is also on exhibit at the Small Mammal

House (cage #33).

New Guinea Native Cat

A recent addition to the Small Mammal House

collection (number 15 on map) is a male New

Guinea ‘‘native cat” (Dasyurus albopunctatus).

Somewhat smaller than a house cat, this

white-spotted mammal is not, in fact, a cat but

a Carnivorous marsupial. The carnivorous

marsupials belong to the family Dasyuridae,

which contains some 50 species ranging in size

from a tiny shrew-like form that is the smallest

of all marsupials to the wolf-like thylacine. The

family also includes the famous Tasmanian

devil (Sarcophilus harrisi). The ‘‘native cats”

or dasyures comprise five species of small

predators from Australia and New Guinea that

reminded early European settlers of the true cats

both in habits and their general appearance.

_were born in late March and are now visible

Many of the marsupial carnivores have evolved

a superficial resemblance to the true carnivores—

a more advanced group of placental mammals.

This process—whereby unrelated animals come

to resemble one another by adapting to similar

ways of life—is known as convergent evolution.

Actually the dasyures resemble the placental

civet family, the viverrids, more than they do

the cats. Little is known of the New Guinea

New Guinea dasyure or “‘native cat.”’

‘native cat’s’’ habits in the wild. It is nocturnal

and sleeps during the day in a nest of dry grass,

leaves, and similar material under a rock or in

a hollow log. It spends most of its time on the

ground but can climb well.

Mammal Notes

Spring births among hoofed mammals include

a bongo (Boocercus eurycerus) (number 3f on

map), a scimitar-horned oryx (Oryx dammah)

number 8c on map), and three sable antelope

Hippotragus niger) (number 3e on map). ...

Two female red kangaroos (Macropus rufus)

have young in their pouches (number 9i on map)

.... Four Utah prairie dogs (Cvnomys parvidens)

above ground (number 17 on map).

In May two female scimitar-horned oryx became

the first animals to be sent to the National Zoo’s

new Conservation Center, which will be used to —

breed animals—particularly endangered species

like the scimitar-horned oryx—in greater numbers

than would be possible in the limited space

available in the Zoo.

New Lorikeet Species

The brightly colored lorikeets are the clowns

of the parrot world. Not only are the multi-

colored feathers of some species reminiscent

of motley, but these parrots appear to be quite

playful in disposition. Two species recently

acquired at the Bird House (number 5 on map)

provide excellent illustrations. These are the

ornate lorikeet (7richo/glossus ornatus) and

the red-collared lorikeet (Trichoglossus

haematodus) in cage #3, immediately to the

left of the front door of the building. The

former species is basically green with the top

of the head dark blue; the nape, cheeks,

throat and breast red and blue; and yellow

streaks at the side of the face. The latter species

is still more spectacularly colored; its head is

blue, its nape is red, its upper back is black,

its lower back is green, and its abdomen and

legs are yellow.

There are two birds of each species on exhibit,

and the members of each pair frequently engage

in playful tussling with each other. In another

example of apparent playful behavior, one bird

may occasionally fly over the wire front of the

cage and, clinging to the wires with its feet,

slide down the wire to the bottom of the cage.

Examples of genuine play behavior, frequently

found in mammals, particularly in the young,

are hard to come by in birds. But the tendency

to play Is correlated with the ability to learn.

(Man, with his enhanced capacity for learning,

also has an apparently enhanced capacity for

play and a greater tendency to continue play

into adult life than most other animals.) And

that play seems to occur with relative frequency

in the lorikeets and in certain other parrots is

not surprising in view of the parrots’ apparently

higher learning abilities relative to those of

most birds.

The red-collared lorikeet belongs to a

widespread species found in much of Indonesia,

New Guinea, and northern Australia, while the

ornate lorikeet is found on the large Indonesian

island of Celebes and a few surrounding smaller

islands. Another, somewhat less brilliantly

colored lorikeet species—the Mount Apo lorikeet

(Trichoglossus johnstoniae)—has also been

acquired recently and is being exhibited in the

turquoise parakeet cage on the rear wall of the

Bird House. This species is notable for its

rarity; it is apparently restricted to Mount Apo

and a few other mountains on the island of

Mindanao in the Philippines, living only between

the altitudes of 4000 and 8500 feet above

sea level.

Collared lorikeet at the Bird House (number 5

on map).

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Connecticut Avenue pedestrian entrance

. Connecticut Avenue vehicular entrance

. Deer and antelope areas (a-j)

. Great Flight Cage

Bird House

Pheasant and crane line (a-u)

. Raptor cages (a-d)

. Delicate-hoofed stock building (a-c)

. Hardy-hoofed stock complex (a-i)

. Panda House (a-c)

. Elephant House

. Water birds (a-e)

. Hawks and owls (a-c)

. Black Rhinoceros Yard

. Small Mammal Building

. Lesser Pandas

. Prairie dogs

. Small carnivores -

. Reptile House

. Tortoise yard

. Monkey House (under construction)

. Lion and Tiger Exhibit (under construction)

. Komodo Dragon

. Bears (a-})

. Cheetah yard

. Water animals (a-c)

. Jaguars and Siamang gibbons (a-b)

. Waterfowl ponds (a-d)

. Police Station—Restrooms—First Aid

. Restaurant

. Picnic Area

. Window Shop

. Souvenir Kiosk

. Rock Creek Parkway entrance

. Friends of the National Zoo Education Office

. FONZ Membership and Editorial Offices

are 4Telephone

di ? Restrooms

Ke Trackless Train Stops

gee Parking

——— +» Walking Tour Route

(From the Trackless Train

Stations)

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Connecticut Avenue pedestrian entrance

. Connecticut Avenue vehicular entrance

. Deer and antelope areas (a-j)

. Great Flight Cage

Bird House

Pheasant and crane line (a-u)

Raptor cages (a-d)

Delicate-hoofed stock building (a-c)

. Hardy-hoofed stock complex (a-i)

. Panda House (a-c)

Elephant House

. Water birds (a-e)

. Hawks and owls (a-c)

. Black Rhinoceros Yard

. Small Mammal Building

. Lesser Pandas

. Prairie dogs

. small carnivores -

. Reptile House

. Tortoise yard

. Monkey House (under construction)

. Lion and Tiger Exhibit (under construction)

. Komodo Dragon

. Bears (a-j)

. Cheetah yard

. Water animals (a-c)

egenangtnse st — is "838

. Jaguars and Siamang gibbons (a-b)

. Waterfowl ponds (a-d)

. Police Station—Restrooms—First Aid

. Restaurant

. Picnic Area

. Window Shop

. Friends of the National Zoo Education Office

Telephone

Restrooms

Trackless Train Stops

Souvenir Kiosk

Rock Creek Parkway entrance Parking

FONZ Membership and Editorial Offices

—— — ~» Walking Tour Route

(From the Trackless Train

Stations)

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Vulturine Guineafowl

Recent additions to the Bird House collection

include four vulturine guineafowl (Acry//ium

vulturinum), two located in the open-fronted

enclosure to the right of the front door of the

building (number 5 on map), and two in the

Great Flight Cage (number four on map).

Native to Africa south of the Sahara and

Madagascar, the guinea-fowl form a group of

six species of gallinaceous birds—that is, birds

related to the chickens and pheasants. This

particular species inhabits the dry steppes of

East Africa from southern Ethiopia and Somalia

to northeastern Tanzania. Its name derives

from the fact that, like that of a vulture, its

head is bare of feathers. It is by no means a

scavenger, however, but feeds mainly on seeds

and insects.

Guineafowl were domesticated by the Greeks

and Romans but disappeared in Europe early

in the Christian era. The helmeted guineafowl

(Numida meleagris) was brought back from

the Guinea coast by the Portuguese in the

Fifteenth Century and domesticated. It still

Vulturine guineafowl.

survives as a domestic species, but it has never

proved as popular as the chicken or the turkey

because of its monogamous life-style and

because of its relatively low egg-yield per hen.

Vulturine guineafowl are also monogamous.

Each pair constructs a simple nest by digging

a hollow in the ground and lining it with

trampled grass. The nest is usually concealed

in tall grass or among rocks and bushes. The

hen lays eight to 15 pale cream or buff eggs

with brown and white specks and incubates

them 24 days. After the breeding season,

vulturine guineafowl form large flocks in which

there is apparently a dominance hierarchy or

“peck order.”’ In a conflict the dominant

bird lunges at the lower-status bird with its

head lowered and wings raised over its back.

Bird Notes

A pair of hoopoes (Upupa epops) have eggs in

the large cage to the right of the front door of

the Bird House. .. . The Zoo’s female Andean

cock-of-the-rock (Rupicola peruviana) has

shown signs of building a nest in a closet that

opens onto the indoor flight room at the Bird

House. In the wild this species nests in cave

entrances, and the closet may prove an acceptable

substitute. ... Among many species hatched in

the incubators in the Bird House basement this

spring, some of the most notable ‘were Inca

terns (Larosterna inca) and Swinhoe’s pheasants

(Lophura swinhoe/). The former species, from

the coast of Peru, has not been bred at the

National Zoo before; the adults are located in

the great flight cage (number 4 on map).

Swinhoe’s pheasant (number 6-7 on map) is

close to extinction on its native Taiwan.

iy as oe ‘ some of its better known relatives, and adults

da\ainll ats lala! range between 3 and 5 feet in length. The

Zoo’s specimens are young and less than

2 feet long.

The crocodilians—the alligators, crocodiles,

Ccaimans, and gavials—are an ancient order of

reptiles, which had fully evolved by the

beginning of the Jurassic Period of the earth’s

Smooth-Fronted Caimans history, some 180 million years ago. This

was relatively early in the age of dinosaurs;

and the crocodilians are related to the dinosaurs,

Three smooth-fronted caimans (Paleosuchus being in fact their closest relatives now living.

trigonatus) have recently been placed on Together with the dinosaurs they are grouped

exhibit in cage B-3 at the Reptile House, in a major subdivisian of the reptile class

the rear cage on the crocodilian line. The known as the subclass Archosauria—the ‘‘ruling

caimans are South American relatives of the reptiles.” Members of this group did rule

alligators and crocodiles. This species does the earth in the later Mesozoic Era, but

not reach anywhere near the great size of now all save the crocodilians have vanished.

The Zoo’s three spectacled caimans, their eyes

just above the water line.

However, some of the smaller ruling reptiles

were ancestors of the birds; and in this class—

most successful of vertebrate classes in number

of species and subspecies—the ruling reptile

line has left an important mark on the current

world fauna.

The crocodilians probably owe their persistence

to the fact that they have perfected more than

any other reptiles before or since the role

of relatively large predators in inland waters.

One disadvantage for reptiles assuming an

aquatic life was that in primitive reptiles the

nasal passages opened directly into the front

of the mouth, endangering breathing if the

mouth was opened under water. But the

crocodilians have evolved a bony partition that

separates the nasal passages from the mouth so

that they open into the throat behind a flap of

flesh at the back of the tongue. This flap can

close off the air passages so that, with the

nostrils above water, the crocodilian can

continue to breathe even when its mouth is

open below the water line, as it is when the

crocodilian is capturing or holding onto prey

in the water.

It is interesting to note how many characters

the crocodilians share with other extinct

ruling reptiles and with birds. Many of the

dinosaurs were bipedal, with long and power-

ful hind legs and relatively small forelimbs;

and it was a similar bipedalism that freed the

forelimbs for development as wings and thus

allowed for the evolution of birds. Though

the crocodilians are quadrupedal, they show

the tendency towards longer hind limbs that

characterized the ruling reptiles. Like birds,

the crocodilians have a four-chambered

heart, allowing for much more efficient

circulation of blood than the typical rep-

tilian three-chambered heart. Unlike most

reptiles, crocodilians guard their eggs until

hatching and in the case of some species

females have reported to guard the young for

some time after hatching. The discovery of

one fossil site where dinosaur eggs, young,

and adults were found close together has

opened the possibility that some dinosaurs

also guarded their eggs and young. Thus it

may be that the type of parental care so

familiar and highly evolved in the birds has

roots that extend as far back as the earliest

common ancestors of the ruling reptiles.

A further similarity between the crocodilians

and the birds is the use of ‘‘gizzard stones.”

A crocodilian’s sharp teeth are used for

capturing and holding prey, not for chewing;

the prey is swallowed whole or in large pieces

and is not chewed. But the crocodilian swallows

pebbles which lodge in the muscular part of

the stomach known as the gizzard, and these

aid in grinding up the food; 69 pebbles were

once found in the stomach of a smooth-fronted

caiman. Many birds too swallow pebbles or

grains of sand as gizzard stones.

The smooth-fronted caimans are found in the

Amazon basin, a region which contains greater

diversity of living crocodilians than any other.

They inhabit rocky and swift-moving streams

that are avoided by the larger crocodilian

species. Interlocking bony shields on the back

and belly are believed to be adaptations to

protect them from harm when thrown against

rocks in rapids. The presence of these plates

has apparently made the smooth-fronted

caiman’s hide valueless as leather—a fortunate

circumstance, since hunting for the leather

trade is a major reason why many members of

the ancient crocodilian order are now in danger

of extinction. But no crocodilian can yet be

considered safe from needless human persecution

and habitat destruction, which affect even

species with little economic value.

Reptile Notes

Recent hatchings at the Reptile House have

included several leopard geckos (Eub/epharis

macularis) and a total of 45 Burmese pythons

(Python molurus bivittatus). . .. Three Asiatic

striped ratsnakes (E/aphe taeniura) have been

placed in a new exhibit in cage C-11. These

handsome snakes are Southeast Asian relatives

of the black ratsnake (E/aphe obsoleta

obsoleta) and the corn snake (Elaphe guttata)

native to the eastern United States.

The iguanid lizards (Iguanidae) comprise by

far the largest family of lizards in the New

World; almost three-fifths of the lizard

species found in the United States and Canada

are iguanids. The iguanids are not dominant

in all parts of our continent, however; only

one of the eight species of lizard found in the

District of Columbia, Maryland, and Virginia,

is of this family—the small brownish Northern

fence lizard (Sce/oporus undulatus hyacinthinus).

But for other areas, particularly the Southwest,

it can be said that any lizard encountered is

more likely than not an iguanid; of thirty-six

species recorded for lizard-rich Arizona,

twenty-four are iguanids. And in the Southwest

the iguanids are not only numerous but

conspicuous, including some relatively large

species and species that are more frequently

seen by day than are many of our other lizards.

The two species that are probably the most

familiar to the general public of all North

American lizards are members of the Iguanidae—

the Carolina anole (Ano/is carolinensis) and

the Texas horned lizard (Phyrnosoma cornutum).

Both of these species are frequently sold as

pets and are widely known by their misleading

pet-store names. The former, because of its

color-changing abilities, is sold as a ‘‘chameleon,”’

although the true chameleons are exclusively

Old World lizards. The latter, because of its

broad, flattened body, is often called a ‘horned

toad.’’ These two well known species provide

a good illustration of the diversity of external

appearance found in the family. The Carolina

anole corresponds to the popular conception of

a typical lizard, with its slender body and long

tail. By contrast, the horned lizard, with its

unusual shape and scales that have been modified

into spines lining the body and horns on the

head, is one of the most bizarre in appearance

of all the lizards.

Indeed with some 700 living species the

iguanids have invaded a wide variety of

habitats and assumed a good many shapes

and sizes. The common iguana (/guana

iguana) of tropical America is the largest

New World lizard; it is reported to reach a

length of over six feet, most of which is

tail. (Three specimens are on exhibit in

cage C-26 at the National Zoo’s Reptile

House, number 19 on map.) Many species

are much smaller than this. The Texas tree uta

(Urosaurus ornatus) averages only slightly over

one-and-a-half inches from snout to vent, with a

slender two-inch tail. :

A few of the iguanids have attracted interest

because of their unusual habits. Perhaps the

most remarkable is the marine iguana

(Amblyrhynchus cristatus) of the Galapagos

islands in the Pacific. The marine iguana

lives in groups on the lava-rock beaches of this

volcanic archipelago, feeds on seaweed, and

navigates the surf with ease. Another

The Fiji island iguana (Brachy/ophus fasciatus) lives in surprising

isolation in its Pacific island home; its nearest relatives are in

California, over 5,000 miles away.

outstanding departure from typical lizard pockets in the Old World. If it originated in

ways is found in the'ability of anumber of — the Old World, the difficulty lies in explaining

iguanid species to assume an unusual means the means by which it reached the New World

of locomotion—rearing up on the hind legs and its current virtual absence in the Old World.

to run for a short distance. The collared

lizard (Crotaphytus collaris) of the western In Eurasia, Africa and Australia there exists

United States is an example. The basilisk a family of lizards that is apparently

lizards of the American tropics (Basi/iscus) closely related to the Iguanidae and to a

can even run bipedally over the surface of certain extent parallels them in the habitats

standing water for short distances. it has invaded and the life-styles its members

Though the iguanids are so numerous in the

New World and form so characteristic a part The Carolina anole—sold in pet stores as a

of its reptilian fauna, a few members of this “chameleon’’—is probably the most familiar of

family appear in surprising isolation in two iguanids to North Americans.

: of the Old World. Seven species inhabit ~

adagascar, and one lives on the remote Fiji

Islands in the Pacific. (The Fiji Island iguana,

Brachylophus fasciatus, is on exhibit in cage

E-15 at the Reptile House.) To explain this

widely discontinuous distribution has been

one of the classic problems of zoogeography—

the branch of biology that studies the

geographic ranges of animal species and

groups and attempts to account for them.

The task has been complicated by the fact

that so far few fossil remains of early iguanids—

and of other ancestral lizard forms—have

not been found. Most lizards have been

small-boned and have not made the best of

fossils; in addition, it has been suggested that,

during the great era of fossil discovery in the

Nineteenth Century, workers tended to pay

more attention to the many giant reptiles

of the past at the expense of their less

spectacular cousins. In any event, in the absence

of a detailed fossil record, scientists can only

guess where and when the iguanids originated

and how their present pattern of distribution

came about. But the guess work itself is often

fascinating.

The lizards themselves first appeared, as far

as we know, in the Triassic of Africa, some

200 million years ago. The first undisputed

iguanid remains that have so far been identified

are from the Eocene of North America, about

150 million years later. By that time, however,

the Iguanidae were widespread and diversified

on this continent; and other lizard families that,

on the basis of their physical structure are

considered more advanced than the iguanids

and would be expected to have evolved later

than them, had already made their appearance

and spread widely. Obviously the iguanids

had existed for some time before the Eocene,

but no earlier fossil remains give us a clear

picture of the place and time of their origin.

If the family originated in North America, it is

difficult to explain its occurrence in isolated

The knight anole of Cuba (Anolis equestris) is named for the

helmet-like appearance of its head.

have evolved. This family is known as the

Agamidae, and it would appear to have

evolved from the Iguanidae. (An example

of an agamid at the Reptile House is the

bearded lizard, Amphibolus barbatus,

in cage A-2.) The two differ most

apparently in the structure of their teeth.

Iguanids’ teeth, like those of most lizards,

are similarly shaped throughout the mouth.

The agamids are unique among lizards

in that their teeth are divided into three

types that roughly resemble the incisors,

canines, and molars of mammals. It is a

curious fact that there are no agamids in

the New World or on Madagascar; only in

the Fiji Islands do agamids and iguanids

live side by side.

As for the Fiji Island iguana, it is conjectured

that its ancestors came not from the Old World

but from the New. The gradual island-hopping

that would have been the normal course by

which a lizard species would reach a distant

Pacific island group from Asia would almost

certainly, it is felt, have left surviving iguanid

relatives on some of the islands traversed.

Rather it is asserted that the iguanids must have

reached Fiji by westward colonization from

North America—an ocean voyage of over 5,000

miles. In fact, on the basis of its physical

structure, the Fijian species is held to be most

closely related to the crested lizards

(Dipsosaurus) of Baja California and the

Southwestern United States. Presumably

an ancestral form related to the crested

lizards was rafted across the Pacific as

far as the Fiji Islands on a tree that fell into

the water or by some similar means. All

that would have been necessary would have

been that such a tree contain a male anda

female or even a single gravid female; and

reptiles are well able to survive with no or

minimal food and water long enough to make

such a trip. Similar means must have

brough iguanids to the Galapagos, 600 miles

from the South American mainland.

In view of the almost mutually exclusive

distributions of these two closely related

lizard families, the theory has been proposed

that the Iguanids originated in the Old World,

probably in Africa, and then, after spreading

as far as the New World, were eliminated in

their original Old World home wherever they

were in competition with the more successful

and more recently evolved agamids. Only on

Madagascar, by this account, did an iguanid

remnant manage to survive; and, since that

island had already been separated from the

mainland before the agamids made their

appearance, the younger family never reached

there. Herpetologists have long considered

the seven Madagascan iguanids the most

primitive in physical structure of living members

of the family; and it is not surprising that they

of all living iguanids should have diverged

least from the family’s hypothetical African

ancestors. The Madagascan fauna is well known

to include a substantial collection of primitive

types whose closest relatives have long since

died out on the African mainland.

If the iguanids evolved in Africa, we should

expect there to be some fossil species from the

Old World. One has been described from

Europe; but it is an incomplete fossil, and some

authorities assert that it must be an agamid.

Moreover, the means by which the iguanids

reached the New World before dying out in

the Old remains to be accounted for.

One explanation that has been proposed in-

volves an intriguing but still controversial theory

Foot of the knight anole, showing flattened digits

that are an adaptation for the arboreal life

characteristic of the anoles.

known by the curious name of the ‘“Gondwana-

land” hypothesis. Certain beds of Permian and

Triassic deposits in India—many of them found

in a formation called the Gondwana beds—

contain plant remains unlike any others found in

Asia but closely resembling plants from the same

era in Australia, Africa, and South America.

As an explanation it was proposed that India,

Africa, Australia, South America, and Antarctica

were originally joined together to form a

southern continent, which was given the name

Gondwanaland. At some point, according to

this theory, the land masses constituting

Gondwanaland broke apart and began drifting to

their present positions, the Indian subcontinent

eventually colliding with Asia to give rise to the

Himalayas. As Gondwanaland apologists

pointed out, the eastern coast of South America

and the western coast of Africa seem to show a

rather neat ‘‘fit,’”’ as does the south coast of

Australia with part of the north coast of

Antarctica. The positions of India and

Madagascar in the hypothetical assemblage

could not, however, be so easily accounted for.

Most geologists tended to discount the

Gondwanaland hypothesis when it was first

proposed. No theory of continental drift

appeared to have more than circumstantial

confirmation; but recently the debate has

been reopened in the light of striking new

evidence. There is a ridge in the center of the

southern Atlantic forming an irregular line the

shape of which corresponds with those of the

coastlines of both South America and Africa.

Along this ridge earthquakes occur frequently,

and the forces that cause them have been present

for millions of years. These forces would have

been quite capable of breaking apart Africa and

South America, and the ridge is located in

exactly the right position for them to have done

so. Evidence from this ridge indicates that the

separation of the two continents must have

begun about 180 million years ago. In terms of

animal life this was the Jurassic period, and early

iguanids could conceivably have existed then on

‘““Gondwanaland.’’ Thus iguanids may have

flourished on the South American section of the

former continent, survived on the Madagascan

section, and been eliminated by competition

on the African section.

Scientists have only recently begun to devote

more than casual study to the behavior of the

iguanid lizards, but already the results have

proved exciting. With few exceptions adult male

iguanids are territorial, and each typically

advertizes his possession of a territory by

displaying in highly stereotyped ways from

prominent places. The displays involve

nodding movements of the head and “push-up”’

movements of the front half of the body.

When the male encounters another male

intruding on his territory, he intensifies

these movements to threaten off the trespasser.

Territorial defense of this sort plays so

important a role in the life of the typical

iguanid that the instinctive behavior patterns

associated with it are among the first to

appear in the newly hatched lizard. Some

iguanids only a few months old—often with

the yolk sacs that have nourished them in

the egg still attached.to their bodies—have

been observed performing the push-up and

nodding movements of adult aggressive

display.

The most spectacular displays of territorial

male iguanids occur in the genus whose members

are known as anoles (Ano/is). Comprising by

far the largest of the iguanid genera, these

mostly small, arboreal lizards represent two-

fifths of all the species in the family. Only two

Aggressive display of a male Jamaican anole (Anolis garmani). Note the extended

dewlap or throat fan; the concentric rings marking it are bright red. The tongue

is protruded and fills with engorged blood.

are found in the United States: the Carolina

anole already mentioned and a closely related

species found only on Key West, Florida. But

in the New World tropics a bewildering

variety of anoles has evolved. Nowhere is

this diversity more apparent than in the West

Indies. Two of the West Indian anoles are on

exhibit at the Reptile House—the Jamaican

anole (Anolis garmani) in cage A-17 and the

knight anole of Cuba (Anolis equestris) in

cage A-18.

The male anole’s aggressive display is

augmented by the extension of a dewlap of

loose throat skin, which is often brightly

colored and marked in a way characteristic of

the species. In the Carolina anole, for instance,

the male’s dewlap extends in display to form

a bright red disk or fan. Many anoles, including

the Carolina anole, also have crests on the nape

and upper back that are erected during the

display. Also the tongue may be protruded;

and in some species it may fill up with blood

and assume a deep purple color. Finally most

male anoles use their color-changing abilities

to further enhance the aggressive display.

The Carolina anole is capable of assuming

only two basic colors, green and brown; but

each may occur in a number of shades. The

male turns a bright green during the aggressive

display. Its color-changing, contrary to popular

belief, is not a simple matter of camouflage

but is influenced by light-intensity, temperature,

and—in aggressive encounters—emotional state.

Under the transparent epidermis of the anole’s

skin there are cells containing yellow pigment.

Beneath these is a layer of cells that reflect blue

light, and still deeper there are cells containing

black pigment. When the anole appears green,

blue light is being reflected by the reflecting

layer through the layer of yellow-pigmented

cells. It appears brown when the black-

pigmented cells send streams of black pigment

into fine processes that extend around the cells

of the blue-reflecting layer, thus preventing

them from reflecting light.

Aggressive display is essentially a means of

communication, warning intruding males

that a resident territorial male is present.

The intruder usually does not challenge the

territory holder but withdraws when

confronted with the display. In the Carolina

anole, interestingly, the submissive intruder

turns brown as he withdraws, in marked

contrast to the bright green victorious

resident. Maintaining territories, in turn,

is important as a means of spacing the

population and dividing resources. Also,

since females are allowed to live on a male’s

territory unmolested, it provides a means

of spreading access to females throughout

the male population. The distribution Is

not necessarily equitable, however. In at

least one species it was found that larger

males had more females on their territories

than smaller males. The size of the male is

itself communicated by the aggressive display,

since he usually postures sideways to an

intruding male.

When a male iguanid encounters a female on his

territory he at first uses display patterns similar

to those he uses when he encounters a male. But

his behavior soon changes when the female’s

response to him indicates her sex. If the female’s

physiological state makes her unresponsive to

courtship, she immediately begins a ritualized

rejection display, rising up from the ground on

all four legs, arching her back, and raising her tail

in the direction of the male. She may then take

a number of short hops away from the male. This

stately performance appears to discourage any

attempt at courtship.

The male’s courtship, in all species in which it

has been observed, follows a similar pattern,

He approaches the female with his head lowered

and begins to nod rapidly. He may follow the

female for a short distance, continuing to nod

his head at intervals. If the female is willing to

breed, she permits him to mount her and grasp

the skin of her nape or shoulder with his mouth.

The male then brings the base of his tail in contact

with the same region on the female. Male lizards

have two copulatory organs—or “‘hemi-penes’’—

enabling the male to curl his tail under the

female’s on either side of her body.

Glimpses into the day-to-day life of iguanid

lizards are rare; the members of this family are

sO numerous and so varied that human curiosity

has so far only scratched the surface. While the

mystery of the family’s distribution remains to

challenge paleontologists, in the case of many

species the barest details of life history are so

poorly known that a patient amateur can

contribute much. And lizard watching is a joy

in itself, whether in the zoo or at a suburban

wood-pile. The lizard’s deliberate movements

seem to accentuate the importance of everything

it is doing, and patience is rewarded with the

sudden emergence of a highly ritualized

behavior pattern such as an aggressive display.

The lizard’s activities may seem simple and few to

us, but there is an intensity in their performance

that seems missing in our own more complex

behavior. As D.H. Lawrence expressed it, ‘If

men were as much men as lizards are lizards,

they would be worth watching.”