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The
jet-black monster roars “Klah, Klah” and pounds his
huge furry chest with muscular arms. The ape’s black, burning
eyes glare into yours. The mouth in his broad, flat face draws
back, showing gleaming white fangs. A thick odor of manure, burned
wood and human sweat fills the air. You stand frozen, expecting
death at any moment. Where is that guide with his gun?
Gorillas frightened the explorers and adventurers who saw them
in Africa beginning almost 2,000 years ago. These men didn’t
take time to study the beast. They either killed the gorilla or
dashed away through the jungle at tremendous speeds. And then
they returned home with stories or even with the terrifying bodies
of slain gorillas. Scientists studying these bodies found similarities
between the gorilla and man. Word spread that gorillas, who walked
like a man on two feet, would kill any man invading their jungle.
Was the gorilla indeed a monster? And just how human was this
beast?
Robert L. Garner, a naturalist or scientist who studies animal
behavior, decided to go to Africa about 100 years ago and study
gorillas. Believing the stories, Dr. Garner built a cage for himself
to ward off savage ape attacks. So there he waited in his cage
day after day, and no gorillas appeared.
Years went by and true gorilla behavior remained a mystery. Then
in 1959 a naturalist named George Shaller walked into the Virunga
Mountains to study the mountain gorilla without a gun. He, and
later Dian Fossey, lived near gorillas for many years, and what
they found would surprise the earlier explorers.
First off, the gorilla is not going to find you tasty because
the only “meat” gorillas eat are grubs and snails. Otherwise,
they munch on grasses, ferns, vines and tree bark. They eat 20
to 40 pounds of plants a day. And so gorillas spend most of their
time chewing, not fighting. Gorillas belch like humans do after
a big meal, and they can also belch on cue. When Dian Fossey belched
while in a group of gorillas, the gorillas belched back at her.
It turns out that gorillas are, in fact, very gentle. Gorilla
groups share food and land with each other and avoid fights. And
if gorillas can disappear into the underbrush before being seen
by man, they do. Mother gorillas tenderly care for their babies,
who ride on her belly or on her side until they are about a year
old. And even after that dad and mom give them a piggyback ride
every so often. Mother gorillas grunt like a pig to reassure their
children. And Dian Fossey discovered that gorillas love to be
tickled. She once saw an old gorilla tickle a baby with a flower
like a kindly grandfather.
The large male who is the leader of a group of females and children
is a kind and tolerant dad. Gorilla fathers, like any good dad,
will attack anyone they feel will hurt their family. But the chest-beating,
screaming and charging are signs of excitement designed to ward
off intruders. Dian Fossey watched two male gorillas scream and
charge at each other for two full days without ever doing battle.
And Ms. Fossey found ways to calm down a chest-thumping, screaming,
excited gorilla. Try any or all of these: raise one arm and scratch
yourself, fold your arms across your chest, belch, keep your head
down, shake your head and make gentle “naoom, naoom”
noises. These actions tell the gorilla you’re a nice person
and mean no harm.
Experts have now seen that, though gorillas can stand on two legs,
their arms are so long that they mostly walk on all fours, resting
on the knuckles of their hands. And as for their intelligence,
gorilla expert Penny Patterson taught her young gorilla Koko to
“talk” in sign language. When the gorilla had learned
500 signs, Koko asked for a real cat. Koko named the cat All Ball
and cared for her cat like any mother would. When All Ball was
killed by a car, Koko cried a sad hooting sound. Then the ape
signed, “Sleep, cat.”
Dian Fossey’s greatest thrill came when a 450-pound gorilla
she had named Peanuts touched her outstretched hand with his own.
And Peanuts was also impressed, racing off to tell his friends
while beating his chest in excitement. And we can learn much from
gorillas. In fact, if man copied the gentle ways of the gorilla,
the world would be a better place to live in.
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Mountain Gorilla Family Structure
Mountain Gorillas are highly social, and live in relatively stable,
cohesive groups held together by long-term bonds between adult
males and females. A typical Mountain Gorilla group is led by
the biggest and strongest mature male gorilla he’s called
a 'silverback' because the hair on a male’s back turns from
black to silvery grey as he matures. This happens when he is between
11 and 13 years old. A silverback’s group normally includes
a sub-adult male or two and a few females and their young.
Mountain
Gorilla Reproduction
Males mature later than females and do not breed until 15 to 20
years of age. About half of all males leave their natal group
at puberty and travel alone or with other subordinate males until
they establish their own group. Once a male has established a
group, he will most likely stay with that group for life unless
he is ousted by another male. Fights for access to females among
dominant silverbacks and lone males are intense and may result
in death.
Adult
females give birth to one baby about every four years although
a surviving infant is produced only every six to eight years due
to high infant mortality in the first three years of life. A baby
gorilla is born weighing 1.8 - 2 kg (4 - 4.4 lbs) after a gestation
period of 251-295 days. Babies are carried around by their mothers
and begin to walk after 30-40 weeks. Gorilla infants are breast
feed for about 12 months. Infant gorillas normally stay with their
mother for 3 to 4 years and mature at around 11 to 12 years old.
They are weaned at 2.5 to 3 years of age.
Young
male and female gorillas are classed as juvenile between the ages
of about three and six. During this stage, both sexes have thick
black hair and black skin. Juveniles of both sexes increase in
size and weight at similar rates for the first six years. At age
six they are about 1.2 metres (4 feet) tall and weigh about 68kg
(150 pounds).
Mountain
Gorilla Life Cycle
Mountain gorillas have a slow rate of reproduction. This slow
reproduction makes this species even more threatened. In a 40-50
year lifetime, a female might have only 2-6 living offspring.
Females give birth for the first time at about age 10 and will
have offspring every four years or more.
Females
mature at about age six and cease to grow taller, although they
continue to gain weight slowly until they reach weights of 113-136kg
(250-300 lbs) at ages of ten to eleven years. Males continue to
grow both in size and weight past the age of six; they do not
reach maturity until they are about twelve years old. Between
the ages of about six and ten years, males retain the uniformly
black hair colour of their youth and are called 'Blackbacks'.
The
potential for population growth for undisturbed mountain gorillas
is comparable to that for human beings. The gestation period is
about nine months. Gorilla mothers with an infant may not have
another for up to four years. There is also no apparent breeding
season, since births of baby gorillas occur throughout the year.
However, due to mishaps and disease, many baby gorillas die in
the first year of life, and nearly half of all gorillas die before
reaching adulthood.
The
maximum life span of mountain gorillas in the wild is difficult
to estimate. The longest-lived gorillas in captivity reached ages
of thirty to thirty-five years. No gorilla has been seen in the
wild that looked as aged as the oldest captive gorillas, so the
life span in the wild is probably somewhat less, perhaps twenty-five
to thirty years.
Mountain
Gorilla Behaviour
The Mountain Gorilla is a highly intelligent and gentle creature.
Despite a ferocious reputation, the gorilla rarely makes use of
his incredible strength. When it comes to defending the family
or breeding rights, however, it's does display its dominance.
Mountain
gorillas wander around a home range of up to 15 square miles (39
square kilometres). They spend much of their time eating. Their
food includes a variety of plants, along with a few insects and
worms. At night the animals make a nest to sleep in. Many lightweight
gorillas nest in trees, making beds of bent branches. The heavier
individuals may nest in grasses on the ground. Babies snuggle
with their mothers for the night.
For
a long time the image most people had of a gorilla encounter included
chest pounding, roaring, charging, and big, bared teeth. But researchers
studying gorillas reveal a very different picture of mountain
gorillas. The animals are peaceful, gentle, social, and mainly
vegetarian creatures. The occasional ferocious-looking, impressive
displays are generally from a male gorilla protecting his family
group from a threat. Gorillas, especially males, have a wide range
of vocal and physical communications. Silverbacks can roar, scream
and bark to deter predators or competitors. They stand on their
legs and beat their large chests, which contain air sacks, to
produce an intimidating thudding sound. They may even charge at
people or gorillas they see as threatening, striking the ground
with their fists in a display of aggression.
Youngsters
tumble, climb, and run playing follow the leader. Another group
plays a rowdy game of king of the mountain. Several adults watch
the action, relaxing nearby. The young mountain gorillas play
under the watchful eyes of their mothers.
Mountain
Gorilla Diet
Mountain gorillas eat large amounts of vegetation and spend about
30 percent of each day foraging for food. They consume roots,
leaves, stems of herbs, vines, bark from trees, shrub-sized plants,
and bamboo shoots.
Mountain
Gorilla Vocalisation and Intelligence
Gorillas can make up to 25 vocalizations such as grunts, laughs,
hoots, barks and screams, each with its own specific meaning.
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