is a nonprofit organization of indi-

viduals and families who are in-

terested in supporting Zoo pro-

grams in education, research, and

conservation.

As members of FONZ, you and your

family receive many benefits—

publications, discount privileges,

and invitations to special programs

and activities—to make your zoo-

going more enjoyable and edu-

cational.

ZooGoer (ISSN: 06313-416X) is

published six times a year by

Friends of the National Zoo, Na-

tional Zoological Park, Washing-

ton, D.C. 20008. Third class mailing

permit 44282.

Subscription as percentage of full

membership dues is $4 a year. Sub-

scription-only membership is $5 a

year and is available only to institu-

tions and to those residing outside

the Washington, D.C., metropolitan

area,

FONZ Board of Directors,

1980-1981

Whayne S. Quin, President; Cecil McLelland,

First Vice President; Victor Delano, Second

Vice President; Robert L. Nelson, Treasurer;

Sally S. Tongren, Secretary; Knox Banner;

Samuel Biddle; Janice A. Booker; William C.

Bryant; Janet Dewart; M. Anthony Gould; Al

Hackl; Stephen T. Hosmer; A. Jose Jones;

Nella C. Manes; Georgianna S. McGuire;

Roscoe M. Moore, Jr.; Monica J. Morgan;

Terry R. Peel; Sylvia L. Samenow; Nancy M.

Schneck; Ross B. Simons.

FONZ Staff

Sabin Robbins, Executive Director; Dennis

Baker, Associate Director; Donna M. Schlegel,

Volunteer and Educational Services; David K.

Krohne, Publications, Fran Bernstein, Mem-

bership; Lonnie Wornom, Merchandising;

James Mustakas, Food Service; Kevin Polen,

Transportation; Norma Gay, Business

Manager.

National Zoological Park Staff

Dr. Theodore H. Reed, Director; Dr. John

Eisenberg, Assistant Director for Animal Pro-

grams; Gaetano Calise, Assistant Director for

Support Services; Vincent J. Doyle, Office of

Management Services, Dr. Robert Hoage,

Special Assistant to the Director; Jaren

Horsley, Executive Assistant, Office of Animal

Programs.

National Zoological Park

Department Heads

Dr. Edwin Gould, Mammalogy; Dr. Eugene

Morton, Acting, Ornithology; Dr. Dale

Marcellini, Herpetology; Judy White, Edu-

cation; Dr. Mitchell Bush, Animal Health,

Dr. Richard Montali, Pathology; Dr. Devra

Kleiman, Zoological Research; Dr. Christen

Wemmer, Front Royal Conservation Center;

Donald Muddiman, Construction Manage-

ment; Emanuel Petrella, Facilities Manage-

ment; Robert Mulcahy, Graphics and Ex-

hibits; Samuel Middleton, Police and Safety.

Volume 10, Number 4

July-August 1981

David K. Krohne

Editorial and Art Director

Mary C. Massey

Consulting Editor

Scott Bushnell

Layout and Production

Assistant

Front Cover: Atjeh’s contented

expression seems to suggest that

happiness is a ripe banana. The

orangutan’s diet is composed mainly

of fruit—a factor that is contributing

to the disappearance of the species in

the wild.

Photograph by Jessie Cohen, NZP

Office of Graphics and Exhibits.

Back Cover. The young orangutans

spend much of their time in the

spacious yard at the Great Ape

House investigating visitors.

Ilene Berg, NZP Office of Public Affairs

The sight of Tomoka standing on all

fours in the grass, disdainfully look-

ing at the visitors in the bright summer

sun, was a dream come true. When he

was a baby, I promised him that someday

he would have a spacious, grassy yard to

play in—with no bars and no wires. To

see him stand there now, regally sur-

veying his domain, is all the reward one

could ask for all the years of planning

and striving to get him a new home. The

months we spent with the architects,

planning commissions, contractors, and

budget officials were all worth it.

The interior of the new Great Ape

House is magnificent and inspiring. The

spacious exhibition areas for the ani-

mals, the trees, and the close association

between the animals and the visitors

(that is, with little more than an inch of

glass between them) are rewarding to

behold. We finally have large cages for

our apes and handsome trees for them to

climb. We also have good visibility for

the public. Most visitors do not see the

spacious areas for the keepers’ comfort

and safety or the downstairs retirement

dens for the apes. The animals now have

a place to call their own where they can

go when they don’t want to look at the

public. The apes haven't said anything

yet about the kitchen, refrigerators,

locker rooms, and offices for their

human companions, but I am sure they

benefit from these amenities.

In a few years, the plants that form a

backdrop to the exhibit areas will grow

to provide the illusion of the lush green

forests from which these animals come.

The artificial trees with some flexible

branches are an innovation for us. There

was some question whether the mature

gorillas would use them, since they had

not seen trees for most of their lives. In

fact, Tomoka and the young orangutans

have spent all their lives in zoos. It was

very heartwarming to see the adult go-

rillas make their first tentative use of the

trees, and now they are into them fre-

quently. The young orangutans, of

course, are having a ball!

We've had some nice compliments on

the building from humans, but I think

the best compliment is the reaction of

the animals. They give every indication

that they enjoy their new quarters and

are comfortable.

What more could a zoo director ask than

to have his visitors and his animals

happy? The answer, of course, is more

baby animals, but I'm sure that in time

our new Ape House will be blessed with

the pitter-patter of baby orangutans and

gorillas. Until that time, I shall enjoy

watching the people watch the animals

and the animals watch the people—all

having a good time.

Theodore H. Reed, Director

National Zoological Park

suqryxg puv sorgdvidy fo 24{O dZN ‘Uayoo atssal

The Ultimate Ape House

History—of a sort—was made in

July when three of the National

Zoo's gorillas cautiously left the

comfort of their new home to ex-

plore their outside yards despite

blistering heat and engulfing

humidity. It was the first time

Nikumba, the oldest of the Zoo's

gorillas, had the run of the land

after more than twenty years in

captivity. And for females M’wasi

and Femelle, it was the first oppor-

tunity to roam through an open

space with lush grass.

Whether it was the weather or the

strangeness of the situation, the

gorillas were not outside very long.

The television crews and news-

paper reporters—plus Zoo keepers,

FONZ volunteers, and a few visi-

tors who happened upon the his-

toric event—were all glad to get

back to the comfort of their air-

conditioned surroundings, too.

Ed Gold and David K. Krohne

Jessie Cohen, NZP Office of Graphics and Exhibits

The Zoo's Great Ape House combines the best of modern technology, animal

management experience, and naturalness to provide deluxe accommodations for the

gorillas and orangutans.

Opposite: M'wasi cautiously ponders the world outside before venturing into the

yard at the Great Ape House for the first time.

David K. Krohne

Keeper Doug Donald prepares an afternoon meal for the gorillas in the kitchen of the

Great Ape House.

The gorillas’ introduction to their

outside yard was greeted with as

little fanfare as the opening of the

Zoo's new $2.9 million Great Ape

House in April. But the two events

mark a quantum jump in the care,

management, and exhibition of the

great apes at the National Zoo.

The opening of the Great Ape

House is the latest event in the

implementation of a master im-

provement plan launched by the

Zoo in 1961. The construction and

renovation has improved the living

conditions of many species, but it

took twenty years to have a major

impact on the lives of man’s closest

relatives—the great apes.

The old Small Mammal/Great Ape

House, currently undergoing com-

plete interior renovation as a home

for the Zoo's small mammals, was

built in 1937. “The cages for the

great apes,” according to mam-

malogist Miles Roberts, “were de-

signed to exhibit animals and keep

them from getting out. They

weren't designed to meet the ani-

mals’ needs.”

Great apes have been kept in cap-

tivity for over 100 years, but they

did not fare well for many years

because of their susceptibility to

human respiratory diseases and be-

cause little was known of how

best to care for them in captivity.

The only way to acquire apes for

zoos was to capture them in the

wild after killing the mother, and

there was very little data on the

feeding and management of the

apes in captivity. Fortunately, most

zoos throughout the world now

accept only apes that have been

born in captivity.

When the apes’ former home was

built in 1937, the primary concerns

were to keep them contained and

to keep them healthy. Cages had to

be escape-proof, so the prevailing

method of using 3/4-inch bars was

employed. The other primary con-

sideration was hygiene, so the

cages had to be easy to disinfect

and clean, and glass was installed

in front of the cages to protect

the apes from human respiratory

diseases.

Then, as now, there were two op-

posing points of view about how

apes ought to be kept in zoos. The

hygienic school emphasized pro-

tecting the apes’ health; cages

tended to be small and easy to

clean. The opposing school held

that apes needed to be kept in the

most natural social and environ-

mental conditions in order to keep

them active and content. Both view-

points were given serious consid-

eration in the design of the Zoo's

new Great Ape House.

Zoo staff members had to acquaint

the architects with the special

requirements of housing such

large, intelligent, and strong

animals. The architects, in turn,

had to inform Zoo staff members

what materials and designs could

best meet those needs. The design

team visited other ape facilities and

chose the best features from zoos

in Cincinnati, San Diego, Chicago,

Basel, Zurich, and Frankfurt.

Design considerations included

scale, types of spaces, vantage

points for visitors, barriers, and

materials. ‘When we sat down to

think about a new ape house,”

Roberts recalled, ‘we wanted to do

several things. We wanted to

exhibit the animals much more

aesthetically, without bars, so visi-

tors got a much better feeling not

only about the animals but also

about the way we were taking care

of them.”

“We also wanted to provide for the

animals to live happier lives, to give

them a lot more space and an

environment that would provide

variety,” Roberts explained. ‘By

that I mean that we want to give

them choices: whether they want to

Mike Murdoch, NZP Office of Graphics and Exhibi

Workmen install panels of 1%-inch-thick laminated glass—the only barrier between

the great apes and visitors.

be on view or not, up or down, on

warm floors or cool floors. We want

them to be comfortable mentally

and physically.”

Two thirds of the building's 16,000

square feet is given over to the

apes. The gorillas and orangutans

each have four large rooms two or

three stories high. The bars are

gone—and the effect can be un-

settling for the unsuspecting visi-

tor! All that separates the apes

from the public are structural

panes of 1%-inch-thick laminated

glass which are tilted slightly to

reduce reflection and glare. Natu-

ral light from skylights floods each

room. The light in the public areas

is tinted slightly, also to reduce

glare. Lush tropical plants con-

tribute to the jungle-like atmos-

phere of the public area, and plants

will eventually cover the walls be-

hind the apes’ enclosures.

The building itself is something of

an architectural wonder. The ma-

jor problem, according to Roberts,

was “trying to fit the size, number,

and configuration of cages we

wanted in the space we wanted.

The architects had to be happy

with it, and the animal managers

had to be happy with the way the

building was going to function.”

The architects’ biggest challenge

was creating a building that would

not jar the eye of the viewer. They

Jessie Cohen, NZP Office of Graphics and Exhibits

wanted to create an unobtrusive

building that would not compete

with the landscape, and they

solved the problem by submerging

much of the structure below

ground level.

The new facility represents many

innovations in the housing and

management of apes. A primary

consideration was reducing bore-

dom for these intelligent animals.

As Roberts put it, “We want to

keep them interested, and we're

going to throw out a number of

possibilities.”

One is television. The apes seem to

Large exhibit enclosures are provided with fiberglass-gunite trees and ropes for the

apes to climb on.

like to watch programs on their

own TV set—a gift from FONZ—

but keepers are not sure whether

they translate the two-dimensional

image on the screen to an under-

standing of the three-dimensional

figures depicted. They seem to like

active, noisy shows, but are also

reported to be among the millions

who watch soap operas.

When they are separated, the apes

will be taken to one of several hold-

ing rooms. Clean, well-lit, and

easily accessible, these areas facili-

tate much more efficient care of

the animals. When an animal is

quarantined, another architectural

innovation comes into play: a sepa-

rate air system has a negative air

flow so the sick animal does not

infect healthy animals in other

parts of the building. In fact, there

are three separate air systems: one

serves the public areas, another the

quarantine areas, and a third, the

animals’ enclosures.

All the enclosures have sculptured

fiber glass-gunite “trees” for

climbing. The branches are flexible

to provide a natural spring as the

apes move across them. There are

also thick ropes in the cages.

Roberts notes that many subtle

things go on between animals, ‘too

subtle for us to see sometimes.”

Some of them can teach us a great

deal about how the animals inter-

act. ‘For instance, a gorilla will sit

at one end of the rope while

another sits at the other end. The

dominant gorilla will take the rope

and shake it. The other one sud-

denly looks around with a nervous

expression and gets down off the

rope.”

In the wild, apes usually avoid

water. Neither gorillas nor orangu-

tans can swim. However, in cap-

tivity some seem to like water, so

there are pools both inside and in

the yards. Drinking water comes

from devices called “lickers.” They

are similar to faucets, but instead of

a handle to turn on the water there

is a movable stick that bends and

lets the water through. To get a

drink, the animal just puts its

mouth on the “licker.”

Special heat pads are built into the

floor of each animal area. They can

be set at different temperatures to

allow the animals to choose what is

most comfortable for them.

Innovations in animal manage-

ment are taking place, too. In the

past, the apes were fed twice a day.

“It's very unnatural,” Roberts adds,

“for gorillas and orangutans to eat a

big meal in the morning and a big

meal in the afternoon. They like to

eat during the day in small quanti-

ties.” So the apes are now fed

throughout the day, and some of the

food is hidden in the branches of the

“trees” to provide diversion.

Perhaps the greatest advantage of

the new Great Ape House is that it

will enable the Zoo to expand its

gorilla population in a group struc-

ture similar to that in the wild. The

social setting provides a positive

psychological stimulus and is al-

ready achieving one of the Zoo's

major goals for the apes—social

interaction. With luck and time, it

may even lead to mating.

The accommodations for the

orangutans are similar to those of

the gorillas. However, orangutans

in the wild spend most of their time

in trees, so their climbing sculp-

tures are more vertically oriented

than those of the gorillas. The ceil-

ings in their rooms are also higher

than those in the gorillas’.

Spacious outdoor yards are pro-

vided for both species. Glass and

open moat barriers separate the

animals from visitors.

Zoo staff members and the archi-

tects have gone to great lengths to

insure that the new Great Ape

House is one of the finest in the

world. It combines the best of

modern technology, animal man-

agement experience, and natural-

ness to provide an unparalleled ex-

perience for Zoo visitors and the

finest of deluxe accommodations

for its residents.

Born at the National Zoo in 1966, Atjeh has still not reached his maximum size. His fleshy cheek pads are still growing, his beard will

become longer, and his hair will darken with age. Also known as “Junior,” he has a very gentle, outgoing personality.

Jessie Cohen, NZP Office of Graphics and Exhibi

“In this realm there be apes of

diverse sorts,” wrote Marco Polo

from Penai, Northern Sumatra, in

1319. “They are small, having a face

like a child, and those of that

country do slaye them and dress

them in sweet spices.”

During the 350 years after Polo's

description of what could have been

a gibbon or an orangutan, other

travelers reported great red man-

apes which never descended to the

ground and lived alone in the

forests of the East Indies. In 1658,

naturalist Jacobus Bontius obtained

a specimen of a large ape and

shipped it home in a keg of rum. His

description of the creature's anat-

omy is the first scientific record of

the orangutan.

By the 1850s, anumber of explorer-

naturalists had visited the Indo-

nesian archipelago and had de-

The Red Ape

Miles Roberts

scribed orangutans both alive and

dead. Most recognized that the

orangutan was somehow different

from the African apes—the chim-

panzee and gorilla—but the dis-

tinction was hazy: Today we view

the orangutan as the “deviant” ape,

sharing little but ancestry with its

African brethren.

The orangutan is classified with the

gorilla, chimpanzee, and pygmy

chimpanzee in the family Pongidae

(from the Congolese mpongi mean-

ing “gorilla’). It is the only member

of the family not living in Africa.

The fossil record tells us that the

orangutan evolved from a proto-ape

called Dryopithecus (‘‘oak ape’) that

lived several million years ago inthe

area that is now northern India and

Pakistan. Fossil remains of animals

closely resembling the modern-day

orangutan have been found in

southern China and northern

Vietnam. Remains less than 10,000

years old have also been discovered

in Indochina, indicating that the

orangutan may have survived on

the mainland at least until the end

of the Ice Age.

Cooling temperatures during the

Ice Age caused a southerly shift in

the tropical ecosystem in which the

orangutan lived. As the glaciers

expanded, the sea level dropped,

and some of the islands that now

form the Indonesian Archipelago

were joined by land bridges. During

one or more of the periods when

Sumatra, Java, and Borneo were

connected, the ancestor of the

modern orangutan made its move

onto the Sunda shelf. The rise in sea

level following the Ice Age once

again isolated these islands from

one another, forming the geo-

graphic configuration we can see in

the atlas today.

Today the orangutan survives only

on Borneo and Sumatra, having

long since become extinct on the

Asian mainland and on the island of

Java. The reason for its extinction in

these areas is not definitely known,

but some scientists have linked its

demise with the presence of the

early hominid Homo erectus in

these same areas. Scientists are not

suggesting that there was direct

competition between the arboreal

fruit-eating orangutan and the ter-

restial hunter Homo erectus. Rather,

early humans may have hunted the

orangutan to extinction. Orangutan

remains have been found in pre-

historic kitchen middens, and even

today primitive tribes in isolated

parts of Borneo hunt and eat

orangutans.

The remaining orangutans have a

remarkably small geographic range.

Populations are fragmented and

small enough to make the orangu-

tan the most endangered ape. In _

Sumatra, a population of about

4000 survives in a tiny area at the

northern tip of the island. Its habi-

tat is threatened on all sides by

intensive cultivation and timber-

ing. On Borneo, the orangutan fares

somewhat better; available habitat

is four times that on Sumatra. Un-

fortunately, the remaining forest is

being invaded by humans dividing a

once continuous habitat into

Bonnie was born at the Rio Grande Zoo in Albuquerque in 1976. She loves her pockets or “islands.” And therein

outdoor swimming pool and also likes to play with the tub in her enclosure.

Jessie Cohen, NZP Office of Graphics and Exhibi

lies the plight of the orangutan. It is

becoming “over-islandized.”

Scientists have known for some

time that species inhabiting islands

are considerably more susceptible

to extinction than closely related

forms living just a few miles away

on the mainland. So the orangutan

has two strikes against it: first, it

retreated to the islands of Sumatra

and Borneo; and second, the habitat

on each of these islands has been

further chopped up into small

parcels. This may be a handicap that

the species cannot overcome, and

the orangutan will most likely be

extinct in the wild by the turn of the

century.

The imminent extinction of this

magnificent anthropoid has stimu-

lated a number of field studies; in

fact, the orangutan has become one

of the most intensively studied of

all primates. George Schaller, John

MacKinnon, Birute Galdikas, and

the Rijksens have contributed long-

term studies that have helped reveal

the secrets of orangutan life.

The most puzzling features of

orangutan lifestyle are its almost

totally arb nd solitary habits.

Why do these large animals persist

in living in the trees and alone in

such uncharacteristic fashion for a

primate? For the answer, we must

start with the fossil record.

Jessie Cohen, NZP Office of Graphics and Exhibits

Pensi was born at the Grant Park Zoo in Atlanta in 1967 and lived there in a family

group until she was brought to Washington as a mate for Atjeh. They have had three

babies; one died soon after birth. Pensi is shy and quiet, and she likes to put things on

her head. :

Extinct orangutans were just as

arboreal as the modern-day forms,

and they were also about fifteen

percent larger. Large size may have

originally been an anti-predator

defense mechanism, and the

males—being considerably larger

than the females—may have had a

group protection role much like

that of the male in modern gorilla

society.

The arboreal habit of the orangu-

tan may be an anti-predator mecha-

nism, but it is more explainable in

terms of foraging strategy—what an

animal eats and how it gets it. If you

are going to be large, either to avoid

predators or because large size helps

you compete for a mate, you need a

high-energy source of food. Fruits

are a good source of concentrated

energy, and in the tropical forest

there are always some fruits avail-

able throughout the year. But you

cannot just sit around waiting for

fruits to ripen and drop to the

ground, because gibbons, siamangs,

binturongs, monkeys, giant squir-

rels, fruit bats, and hornbills will get

the fruit in the trees, and the

muntjacs, sun bears, wild pigs, and

other monkeys are waiting for it on

the ground. Your best strategy is to

beat the competition to the source

of the fruit, which, in the tropical

forest, is in the canopy, and this

means you have to be arboreal.

Once you are arboreal, your large

size helps you chase away or in-

timidate competing species. So

things start to fit together at some

cost.

The problem with being a fruit-

eating specialist is that, unlike

leaves, fruits are not continuously

available throughout the forest.

Different species bear fruit at dif-

ferent times of the year, and fre-

quently individual trees of the same

species may be 100 yards or more

away from each other. Given the

irregular nature of the fruiting

season and the widely dispersed

nature of tree species in the tropical

forest, it is clear that it may take a

fairly large area to support a large

fruit specialist such as an orangu-

tan. Herein lies the secret of the

more or less solitary nature of the

orangutan. Because these large and

relatively immobile animals can

only forage in a small area each day,

it helps if individuals split up into

small foraging units. Males, with a

body mass equivalent to that of a

female and her dependent young,

forage alone, while females tend to

feed with their young. Juveniles—

those who have left their mothers—

may form temporary associations

until they become too large to

forage effectively in groups. At this

Jessie Cohen, NZP Office of Graphics and Exhibits

Indah, daughter of Atjeh and Pensi, was born at the National Zoo in August 1980. She

is being raised with other baby orangutans at the San Diego Zoo.

time they, too, become more

solitary.

This social system is not really

“solitary” in the strict sense, and

individuals are far from asocial. One

scientist has called the orangutan

“desocialized,"’ meaning that the

lack of predation pressures and

other environmental challenges has

required a once close-knit male-

female social structure to become

more loosely constructed. Many

behaviors that help strengthen

social bonds in other primates, such

as grooming and mutual play, are

less evident in the orangutan, and

adults live most of their lives out of

one another's sight. But social

signals—in the form of vocaliza-

tions and other long-distance sound

displays—do persist in a much

more dispersed fashion. In this

sense, the orangutan lives in an

“expanded” social group.

The social organization, anatomy,

and behavior of the orangutan are

products of evolution that take

centuries and generations to change

Jessie Cohen, NZP Office of Graphics and Exhibits

Azy (left)i irst second-generation orangutan born in America. He and Bonnie

(right) have been together since they were babies, and we hope that one day they will

continue the orangutan family begun with Azy’s grandparents Archie and Jennie.

significantly. The pity is that the

orangutan is adapted to a tropical

forest ecosystem that is rapidly

being destroyed by resource-hungry

humans, and the orangutan cannot

adapt quickly enough to these

changes. Unless “progress” is halted

in Borneo and Sumatra, the orangu-

tan will be extinct except for the

few captive survivors.

Captive propagation of the orangu-

tan takes on an urgent nature as the

lifespan of the species in the wild

ticks off with every acre deforested.

The objective must be to maintain a

population large enough to provide

significant genetic variability that

also breeds well enough to become

self-sustaining. Unfortunately, this

goal has not yet been achieved. This

is particularly disturbing in view of

the fact that orangutans have been

maintained in captivity for over 100

years. The captive population size is

well over 800; no other endangered

species enjoys such a large popula-

tion in Captivity.

Ste aah Sasi SS

The key to success is in making the

captive population self-sustaining:

that is, ensuring that no additional

wild-caught animals need to be

added to the population. Zoo people

often refer to it as “multiple-genera-

tion reproduction,” which simply

means that young are born to

parents who were themselves born

in captivity. Obviously, self-

sustaining populations depend on

multiple-generation reproduction.

The alarming fact of orangutan

propagation is that it was not until

1977 that the first second-genera-

tion orangutan was born in

captivity. That special orangutan is

Azy, who is on exhibit in the new

Great Ape House with his mother

Pensi, his father Atjeh, and his

childhood companion Bonnie. He

represents an important milestone

in the role zoos are playing in

the conservation of this endangered

species. Since Azy’'s birth, a few

more second-generation animals

have been born in zoos. Among

them is Azy’s sister Indah, born last

year and currently being raised with

other orangutan babies at the San

Diego Zoo. Thus, the captive repro-

duction effort appears to be making

significant—if late—progress. Per-

haps zoos will be able to sustain a

large enough breeding population

before extinction in the wild occurs.

It will be a close race—and we may

not win.

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ed from A

to have bab

1979. M'wasi will probably never be able

M'wasi was probably born in 1963 or 1964 and was obta

since

The Gentle Giant

The first recorded sighting of goril-

las in the wild occurred in 460 B.C.

when a group of sailors and soldiers

from Carthage set out to explore

Africa. With Hanno as their com-

mander, they sailed to parts of

Africa previously unexplored. The

Carthaginians encountered “gigan-

tic black people that were covered

with hair.” Most likely these were

gorillas. They tried to capture and

enslave these “creatures,” but were

only able to kill and skin a few. The

skins were taken back to Carthage

where they were hung in a temple.

Through the years, many explorers

went to Africa to hunt, capture, and

study. But the first detailed scien-

tific data about gorillas was not

collected until the early 1860s

when the American explorer Paul

Du Chaillu acquired specimens to

measure.

David Baer and Melanie Bond

From earliest accounts to recent

movies, the gorilla has been por-

trayed as a fierce, terrifying animal.

Behavioral and ecological research

by George Schaller and more re-

cently by Dian Fossey has erased

these ‘King Kong” myths.

The gorilla is the largest living

primate and is often described as

“the gentle giant” because of its

placid disposition. There are two

subspecies of gorillas: the lowland

(or coastal) gorilla (Gorilla gorilla

gorilla) and the mountain gorilla

(Gorilla gorilla beringei). The major

difference between the two sub-

species is their geographic distri-

bution in Africa. The lowland go-

rilla lives in the lower elevations of

western equatorial Africa (Came-

roon, Rio Muni Zaire),

and the mountain gorilla lives j

the mountains and lowlands of cen-

tral Africa (up to elevations of

~ 11,500 feet). The mountain gorilla

is found in minuscule home ranges

on the slopes of the Virunga vol-

canos of Uganda, Zaire, and

Rwanda. According to Dr. Dian

Fossey, who has studied the wild

mountain gorilla population for

thirteen years, there are no moun-

tain gorillas in captivity in the

United States. Aside from dif-

ferences in geographic distribution,

there are also a number of ana-

tomical differences between the

lowland and mountain gorillas,

even though they are closely re-

lated.

Gorillas, like humans, are primates

and are one of man’s closest living

relatives. According to current

thought, the evolutionary di-

Jessie Cohen, NZP Office of Graphics and Exhibits

Keeper Walter Tucker feeds 26-year- ikumba, who was captured in French

a in 1954.and given to the Zoo by former FONZ President Arthur W.

“Nick” Arundel. Nikumba has sired four offspring, including Tomoka, who is also on

exhibit at the Great Ape House.

vergence between gorillas and man

occurred ten to fifteen million years

ago. Biochemical studies have in-

dicated that the genetic structure of

humans and gorillas is very similar.

This similarity is one reason why

many people study gorillas.

The average brain size of gorillas is

about 32 cubic inches, while man’s

is about 87 cubic inches. There have

been many attempts to test the

intelligence of gorillas, but the

results are inconclusive. There have

also been several attempts to teach

gorillas sign language; again, in-

terpretation of results is difficult.

Natural vocalizations of gorillas

include grunting, and nonverbal

communication includes shaking

trees, throwing objects, and chest-

beating.

In the wild, gorillas travel in groups

of five to fifteen, sometimes up to

Gren Thagmanaeuallyinelades 4

dominant ‘‘silver-backed” male. (so

named because when a male gorilla

is about ten years old his back turns

a silver-gray color), several subordi-

nate males, and several females

with their offspring, In very large

groups, there may be two or three

dominant males. One “‘silver-

backed” male controls the group,

and females usually mate with him.

If the dominant male is confronted

and defeated by another male, he

will relinquish leadership of his

group. Killing is rare during these

dominance interactions. Most

‘

‘fights” are ritualized; that is, spe-

cific displays and vocalizations

usually replace actual fighting and

killing. Many intricate behavioral

cues are employed during these

confrontations.

Like many animals, gorilla groups—

or troops—travel within an area

called a home range; it can be shared

by more than one troop. The area is

usually ten to fifteen square miles.

The dominant male makes de-

cisions as to which direction and

how fast the group will travel and

where it will stop to feed. He is also

responsible for protecting his troop.

Depending on food availability,

gorillas may travel as little as a few

hundred feet or as much as three

miles in one day. At night they stop

and build nests by intertwining

eae ae aceos aie nec. are

made on the ground or in trees, but

they are rarely more than thirty feet

above the ground. Whether the

nests are built on the ground or in

trees depends on the local habitat.

The nests are used for only one

night; in the morning the troop

moves on in search of food.

Unlike fruit-eating orangutans and

chimpanzees, gorillas eat roots,

bark, leaves, flowers, buds, pith, and

sometimes fruit of many different

plants. Mountain gorillas eat

nettles, thistles, wild celery, goose-

grass, dock, sorrel, and many other

plants. The diet of lowland gorillas

includes ginger fruits and piths,

ironwood bark, cacao (chocolate]

fruit, banana pith, and the bark,

leaves, and roots of the manioc

(tapioca) plant. These last three

species were introduced for agri-

cultural purposes, as were peanuts,

pineapple, and sugar cane, which

are also favored by gorillas. Wild

vegetation that gorillas would

normally eat is destroyed by native

farmers and replaced with these

crops, but when gorillas substitute

them for items in their natural

diet, they are often killed for their

“crime.”

Although many gorillas in captivity

relish a little meat, they are not

known to eat meat in the wild

except in isolated reports of can-

nibalistic infanticide, the meaning

of which is still being debated.

There is no fixed breeding season

for gorillas. Bahies are horn.

throughout the year. Females reach

sexual maturity and begin a thirty-

one-day menstrual cycle when they

are about eight years old. Males do

not appear to have any repro-

ductive cycle as other mammals do,

Jessie Cohen, NZP Office of Graphics and Exhibits

Tomoka, whose name means “son of Moka,” was born at the National Zoo in 1961.

He was the second gorilla born in captivity in the world.

Jessie Cohen, NZP Office of Graphics and Exhibits

and they tend to reach sexual

maturity at about nine or ten years.

A single baby is born after_a gesta-

tion peri about nine months.

Only one instance of twins, which

were fraternal, has ever been re-

ported. Gorilla babies weigh slightly

less than humans. A female gorilla

can bear offspring every three-and-

a-half to four-and-a-half years.

Infant mortality runs as high as

fifty percent in the wild. Many

infants and juveniles die from

respiratory and intestinal diseases,

and humans and leopards often

prey on young gorillas.

Femelle enjoys a snack in the branches of one of her fiberglass-gunite trees. She was

captured in the Cameroon and arrived at the Zoo in 1965. She is the mother of M'geni

Mopaya, born in 1972 and now at the Bronx Zoo. Femelle is a bit overweight and is on

a diet.

When a gorilla is born, it is too small

to hold onto its mother’s back as

many other apes and monkeys do.

The mother must carry the infant

in her arms. The mother-infant

bond is very strong, especially

during the first few months. Within

two months the infant is large

enough to cling to its mother and

ride with her. After another month

the infant can crawl, play, and climb

on vines and trees while its mother

sits nearby and watches.

The early development of the in-

fant’s physical strength is matched

by its growing curiosity. The young

begin to eat plant material when

they are about two months old but

continue to nurse until they are

eighteen months old. When they

are about four months old, they

begin to walk on all fours and to

interact with older animals in the

troop as they start the socializa-

tion process. It is not uncommon for

the young to imitate behavior of the

older animals, such as chest-

beating.

Adult gorillas usually reach a

se ci weigh avo Gonda. gh about 400 pounds; fe-

males are smaller than males. The

life span for gorillas in the wild is

probably fifty years. The oldest

living gorilla in captivity is the

Philadelphia Zoo's Massa, who is

now fifty years old.

The four gorillas currently on ex-

hibit at the National Zoo are of the

lowland subspecies. Nikumba,

Femelle, and M'wasi aptured

in the wild twenty or more years

ago. Tomoka, the son of Nikumba

‘and his first mate Moka (now

deceased), was one of the first

gorillas born and raised in captivity.

Nikumba and Femelle have been

paired since shortly after Moka’s

death in 1968. They have produced

one offspring, M’geni-Mopaya, cur-

rently living with two other young

gorillas at the Bronx Zoo. M'wasi

also lived with a group of gorillas at

the Bronx Zoo until 1979 when she >

Jessie Cohen, NZP Office of Graphics and Exhibits

was sent to the National Zoo as a

companion for Tomoka.

The Great Ape House staff is cur-

rently introducing Femelle, who is a

novice at interacting with another

female, to M’wasi—the “old pro’—

hoping we can eventually form a

more natural social grouping of a

male and two or more females. This

should be a positive experience for

all the animals involved. The go-

rillas should spend less time being

bored and inactive, thus making life

more interesting for them and for

the visitors watching them.

The new social structure could also

spark a seriously waning interest in

reproduction—a fate all too com-

mon for many captive gorillas. In

fact, at a recent symposium in

Atlanta, zoo staff members (in-

cluding representatives from the

National Zoo), veterinarians, be-

havioral scientists, and others met

to discuss the serious problem of

infertility in great apes. Little is

known about the causes and cures

of infertility in humans, and this is

even more true of the “gentle

giants.”

Under an agreement reached sev-

eral years ago by the International

Union of Directors of Zoological

Gardens, zoos that wish to exhibit

gorillas must obtain captive-born

animals. Since the primary method

of acquiring a gorilla for exhibit in

the past involved shooting the

mother and capturing the infant,

this organization realized that

continued removal of young go-

rillas from the wild would also

remove badly needed breeding fe-

males and quicken the demise of

the gorilla. Therefore, it is even

more critical that zoos exhibiting

the species make every possible

effort toward breeding success.

The majestic silver-backed Nikumba

cautiously eyes onlookers from his out-

door yard. This photograph was taken on

the first day he explored his new domain.

How Do You Watch a Gorilla?

You know the answer to that old

joke—very carefully! Behind the

humor lies real truth. Gorillas are

basically shy, peace-loving animals.

By carefully observing them and

watching how they watch you and

each other, you can learn some

very simple rules for gorilla-

watching. |

First, and perhaps most important,

don't stare! When you were very

young, your parents probably

taught you not to stare at people. In

gorilla society it is also considered

rude to stare. A staring gorilla is

communicating a challenge to

fight—or at least an immediate

“cease and desist” command—as

when the silver-backed male group

leader glares at squabbling females

or rowdy youngsters. As you watch

the Zoo's gorillas, you may see

them glance at you from under

Jessie Cohen, NZP Office of Graphics and Exhibits

Melanie Bond

M'wasi exchanges a friendly glance with visitor Brandy Clymire. Crouching with your

back resting against the glass seems to stimulate the animals’ curiosity and encourages

them to investigate at close range.

lowered brows and then look away

quickly as soon as—or perhaps a

split second before—your eyes

meet. This is a courtesy they also

extend to each other, and it is the

behavior you should imitate when

observing them closely.

Size is intimidating to both apes

and humans. Our imaginary mon-

sters—from King Kong to God-

zilla—are all larger than life. Male

gorillas are considerably larger

than females, and this is fitting

since one of the males’ roles is the

defense of their families. When

they wish to impress each other,

both males and females rise up on

their hind legs and beat their

chests or shake branches as part of

their defensive/aggressive displays.

When they wish to appear unin-

timidating, they stand quietly on

all fours with their heads tucked

down, almost slouching. Visitors

can reduce their size—and the ani-

mals’ discomfort—by crouching

down, especially when closely ap-

proaching the glass-fronted en-

closures. |

Since the new Great Ape House

opened, I have been fascinated by

the fact that young children seem

to be excused by the apes for vio-

lating the staring taboo. Perhaps it

is because they are so small, and a

childish stare is an insignificant

threat. I have seen our oldest male

gorilla Nikumba gaze back into a

toddler's eyes with curiosity, only

to turn his back when the child is

joined by his parents.

We have also found that crouching

with your back resting against the

glass seems to stimulate the ani-

mal's curiosity, causing. him to

investigate at close range. It may be

that one back stands out in a sea of

faces.

A good rule of thumb to follow in

determining appropriate gorilla-

watching behavior is to act around

these apes as you would around

small children. Rapid movement,

loud noises, and other forms of

boisterous behavior are unaccepta-

ble to both babies and gorillas.

You may observe other visitors in

the Great Ape House who are not

familiar with these guidelines, and

it may appear that the animals are

not troubled by their inappropriate

Contributors

David Baer, a FONZ Research

Trainee in the summer of 1981, is a

student at the University of Illinois.

Melanie Bond is a keeper at the

Great Ape House.

Ed Gold is a Washington writer

whose work has appeared pre-

viously in ZooGoer.

behavior. Fortunately, our apes

have adjusted quite well to their

new environment and appear to be

less sensitive to the crowds than

we had anticipated. In large meas-

ure this can be attributed to the

“privacy areas” designed into the

new exhibit. Each animal has an

area of refuge to which he can re-

treat if he feels the pressure of too

many eyes. Just knowing they have

a private spot probably makes life a

lot more comfortable for these in-

triguing animals.

Perhaps because they are more soli-

tary in the wild, orangutans do not

display as much sensitivity to close

observation as gorillas do. Even so,

the same suggestions apply for

viewing the orangutans.

Following these simple guidelines

for ape-watching should make for a

more pleasant and interesting visit

on both sides of the glass.

Mammalogist Miles Roberts has

been at the National Zoo for ten

years. He was the subject of a

feature article in the January-

February 1981 ZooGoer and pro-

vided extensive and valuable assis-

tance in the development of this

special Great Ape House issue.