Worlds of David Darling > Children's
Encyclopedia of Science > Could You Ever Speak Chimpanzee? > 1. Animal
COULD YOU EVER SPEAK CHIMPANZEE?
a book in the Could You Ever? series by David Darling
1. Animal Chatter
Birds sing, wolves howl, dolphins click – nearly every animal on Earth
communicates in some way with others of its kind. Animals have reasons for
sending messages. At certain times an individual needs to attract a mate.
At other times it has to defend its territory against competing creatures.
Some species, such as ants, depend for their very lives on working closely
together as a team. To do this, they must constantly exchange messages.
|An owl puffs up its feathers
and spreads its wings in a threat display
Many animals rely heavily on communication by sound, just as humans do.
Finches, for instance, use as many as 25 different calls to inform each
other of the presence of food or enemies. They even have special warning
calls to let other finches know if an attacker is in the air or on the ground.
Sound, though, is not the only way to pass on information in the animal
world. Smell, taste, touch, and body movement can be just as important.
Jive in the Hive
Honeybees have one of the strangest ways to tell each other the location
of a new food supply. When a worker bee has found some flowers containing
nectar, it flies back to the hive and starts to dance on the surface of
|Numbered honeybees in a hive. Honeybees use
body movement, smell, and sound to send messages to other bees.
If the nectar is fairly close to the hive, the returning bee performs what
is called a round dance. It turns in small circles, first to the left and
then to the right. Other workers, by crowding around and constantly touching
the dancing bee, learn that the food source is nearby. From the speed and
length of the dance, they also find out whether the supply of nectar is
rich or poor.
If the nectar is more than about 100 years away, the messenger bee performs
a more complicated routine known as a waggle dance. This time, the bee first
does a short, straight run, waggling its body as it goes. Then it veers
off to one side and returns in a half-circle to its starting point. After
the next straight, waggling run, it goes back in a half-circle on the other
side, making a kind of figure-eight pattern. The direction of the straight
run tells the other bees exactly which way they must fly to locate the food.
The faster the waggle dance is performed, the shorter the distance to the
The honeybees have an amazing system – a simple language based on
body movement, as well as smell and sound. But it is hard to believe that
creatures so small actually think about what they are doing. Their language
is almost certainly one of pure instinct. In other words, they are born
able to communicate in this way; they do not have to learn it.
In 1988, scientists at University College, Cardiff, in Wales, reported the
most detailed study yet of bees' brains. The researchers sliced up each
tiny brain into extremely thin sections. Then, by staining the slices with
various colored eyes, they were able to identify each part of the brain
and build a kind of atlas of the brain's structure. This atlas will now
be used in further work to discover what parts of a bee's brain control
such tasks as decision-making and communication.
|An Incredible Sense of Smell
Of all the signals that pass back and forth between animals, the most
important are those that bring male and female together for mating
and breeding. Without this kind of communication, a species would
rapidly die out.
One of the most incredible signaling systems for attracting mates
is that of the luna moth. The antennas of the male luna moth are so
sensitive that it can detect the scent of a female, in the dark, from
a distance of seven miles!
Alone, an army ant will quickly die. But as part of an enormous swarm, it
is one of the most successful – and deadly – creatures in the
world. Nothing can survive in the path of army ants when they are raiding
|Green tree ants, also known as Australian
weaver ants, join leaves together to make a nest
Like bees, ants are social insects. That means they always live together
in large groups. Each insect works not for itself, but for the good of the
Also like bees, ants communicate in an unusual way. Chemicals produced by
the queen ant are picked up by the workers that attend to her needs. These
chemicals tell the workers what task has to be carried out next. At great
speed, the chemical message is spread throughout the colony by the ants
rubbing antennas with one another.
In the case of army ants, the queen's changing body chemicals cause quite
dramatic effects in the swarm's behavior. At a signal from the queen, hundreds
of thousands of ants march across the forest floor like a brown river, attacking
any creatures in their path. A different signal from the queen instructs
the colony to make camp for the night. The workers hook their legs together
to form a living bivouac, or temporary camp, in a hollow tree or other sheltered
place. The queen and her young are protected deep inside.
Insects such as ants and bees seem to act intelligently when they behave
in this way. It is as if the queen ant, for instance, knew what was needed
to be done next and then sent out the appropriate signal. But, in fact,
all insects act upon instinct. Not even the well-organized army ants really
think about what they are doing or plan ahead. The way they behave is programmed
into them from birth, just as a computer is programmed to carry out certain
tasks over and over again.
Since insects do communicate, we can say that they have a very simple language.
But that language is very fixed. It has not changed over millions of years,
nor will it change in the future. Ants and bees and creatures like them
cannot learn new ideas. Although we may discover how they communicate among
themselves, they could never understand any messages from us.
If we are to have meaningful two-way communication with other species, it
will not be with animals as simple as insects. Instead, we must look at
larger, brainier species and at the way they communicate.
Saying It Without Words
How do you tell someone else that you are frightened, worried, happy, or
angry if you cannot use human words? Animals have developed an incredible
variety of signaling systems to get their point across.
|A red-winged blackbird calls to attract a
mate and to keep other males out of its territory
A cat threatened by a strange dog will suddenly hiss, raise its tail, and
arch its back. This is like saying, "I'm frightened, but if you come any
closer, I'll attack." If you have seen this happen, you will have little
doubt that the dog understands the message! At the very least, the dog will
back off, and often it loses interest in the cat.
Cats, dogs, and many other types of animal are highly territorial. In other
words, they regard a certain patch of ground as their own and will fight
to defend it. Dogs mark the boundaries of their territory with urine. Deer,
on the other hand, give off a strong smelling substance called musk from
the corners of their eyes. They rub the musk onto trees at the edge of their
territory. Other animals recognize these scent warnings and usually stay
away from these areas.
The most important signals are the ones that affect an animal's chance of
survival. Most species do not engage in idle chatter. Instead, they have
a limited vocabulary of sounds and movements, which they use only when necessary.
The more complicated the creature's life-style, the more involved its language
tends to be.
Black-headed gulls – seabirds that nest in large, crowded colonies
– can send at least 30 different messages in their language. They
can also convey shades of meaning by small changes in their posture, or
body position, or by the loudness of their calls. Yet their language has
only 17 distinct signals. How then can they send so many different messages?
|A baby elephant raises its trunk to signal
to its mother that it needs help or wants attention
When it sends a message, a black-headed gull often joins several basic signals
together to make a new signal. For instance, the gull has three separate
ways of posturing to threaten a rival that is coming too near. But if those
three signals are displayed together in a certain order, then they take
on a completely different meaning. They become a courtship signal –
a signal meant to attract a mate.
The gull also extends its range of messages by interpreting signals in different
ways at different times. We do this a great deal in our own language, For
instance, the sound of the tea you drink is exactly like that of
the tee used for holding up a golf ball. Yet from the way in which
the word is used, you can tell what is meant by it. In the same way, the
"choking" display of the black-headed gull has different meanings depending
on the situation. During courtship, it is used by a male bird to send a
message to a passing female: "I own this bit of land, and it would make
a good nest!" But later, when the male has won his mate, the same display
warns other birds, "I own this bit of land, so stay away!"
Some members of the crow family have an even more complex language. In fact,
their babies have to learn crow-talk, just as children must learn a language
such as English. Young jackdaws, for instance, often show no fear of an
approaching predator such as a cat. Only when an adult jackdaw has swooped
down, making an urgent rattling call to warn them, do the youngsters recognize
the danger. Afterward, the young birds know immediately to connect the rattling
call of their elders with a cat or another threat to their safety.
At the University of Rochester in New York, Kathy and Ernest Nordeen have
been studying communication between zebra finches. In 1988, they reported
that a male finch spends the first three or four weeks out of its egg just
listening to the songs of older birds. Then, for the next month, it practices
until its own singing becomes perfect. During the period of learning, the
Nordeens discovered, about 18,000 new cells grow in the young finch's brain.
Cells are the tiny living units that make up every part of an animal's body.
Surprisingly, more than half of the new cells in the finch's brain help
the bird remember its songs!
|Tuning In to Sounds
Hearing plays a vital part in animal communication. The range of sounds
that can be sensed varies greatly from species to species. Many animal
predators need to hear sounds of a higher pitch than humans can hear
because much of their prey makes high-pitched squeaks. The pitch of
a sound – its highness or lowness – can be measured in
hertz (Hz). This is the number of times a sound wave vibrates in a
second. The chart here shows the range over which a number of animals
can "tune in" to their surroundings.
To discover how well humans may be able to "talk" with other species, we
must know the amount of information that animals can send to one another.
Most of the signaling done in the animal world has to do only with survival.
If you are a jackdaw being stalked by the neighborhood cat, all you need
is for your friends to yell "cat!" in bird language. It would not help to
know the cat's color, or its owner's name, or the exact length of its whiskers,
if you were about to be eaten.
Because most animals spend much of their time trying to stay alive, their
languages are short, simple, and to the point. The calls they make, their
gestures and other signals, carry only the most essential information. A
predator is coming! Be my mate" Go away! Feed me! Help me! Since these
are the messages that really matter, they are often the only things for
which the creature has a signal.
Yet not all animal languages are quite so simple. And not all animals are
so set in their ways that they cannot learn new signals or adapt to new