READING PASSAGE 2
You should spend about 20 minutes on Questions 28-40 which
are based on Reading
Passage 3 below.
Elephant communication
A
postdoctoral fellow at Stanford University,
O’Connell-Rodwell has come to Namibia’s
premiere wildlife sanctuary to explore the mysterious and
complex world of elephant
communication. She and her colleagues are part of a
scientific revolution that began
nearly two decades ago with the stunning revelation that
elephants communicate over
long distances using low-frequency sounds, also called
infrasounds, that are too deep to
be heard by most humans.
B
s might be expected, the African elephant’s ability to sense
seismic sound may begin in
the ears. The hammer bone of the elephant’s inner ear is
proportionally very large for a
mammal, buy typical for animals that use vibrational
signals. It may, therefore, be a sign
that elephants can communicate with seismic sounds. Also,
the elephant and its relative
the manatee are unique among mammals in having reverted to a
reptilian-like cochlear
structure in the inner ear. The cochlea of reptiles
facilitates a keen sensitivity to
vibrations and may do the same in elephants.
C
But other aspects of elephant anatomy also support that
ability. First, their enormous
bodies, which allow them to generate low-frequency sounds
almost as powerful as those
of a jet takeoff, provide ideal frames for receiving ground
vibrations and conducting
them to the inner ear. Second, the elephant’s toe bones rest
on a fatty pad that might
help focus vibrations from the ground into the bone.
Finally, the elephant’s enormous
brain lies in the cranial cavity behind the eyes in line
with the auditory canal. The front
of the skull is riddled with sinus cavities that may
function as resonating chambers for
vibrations from the ground.
D
ow the elephants sense these vibrations is still unknown,
but O’Connell-Rodwell who
just earned a graduate degree in entomology at the
University of Hawaii at Manoa,
suspects the pachyderms are “listening” with their trunks
and feet. The trunk may be the
most versatile appendage in nature. Its uses include
drinking, bathing, smelling, feeding
and scratching. Both trunk and feet contain two kinds of
pressure-sensitive nerve
endings – one that detects infrasonic vibrations and another
that responds to vibrations
with slightly higher frequencies. For O’Connell-Rodwell, the
future of the research is
boundless and unpredictable: “Our work is really at the
interface of geophysics,
neurophysiology and ecology,” she says. “We’re asking
questions that no one has really
dealt with before.”
E
Scientists have long known that seismic communication is common
in small animals,
including spiders, scorpions, insects and a number of
vertebrate species such as whitelipped
frogs, blind mole rats, kangaroo rats and golden moles. They
also have found
evidence of seismic sensitivity in elephant seals – 2-ton
marine mammals that are not
related to elephants. But O’Connell-Rodwell was the first to
suggest that a large land
animal also in sending and receiving seismic messages.
O’Connell-Rodwell noticed
something about the freezing behavior of Etosha’s six-ton
bulls that reminded her of the
tiny insects back in her lab. “I did my masters thesis on
seismic communication in
planthoppers,” she says. “I’d put a male planthopper on a
stem and playback a female
call, and the male would do the same thing the elephants
were doing: He would freeze,
then press down on his legs, go forward a little bit, then
freeze again. It was just so
fascinating to me, and it’s what got me to think, maybe
there’s something else going on
other than acoustic communication.”
F
Scientists have determined that an elephant’s ability to
communicate over long
distances is essential for its survival, particularly in a
place like Etosha, where more than
2,400 savanna elephants range over an area larger than New
Jersey. The difficulty of
finding a mate in this vast wilderness is compounded by
elephant reproductive biology.
Females breed only when in estrus – a period of sexual
arousal that occurs every two
years and lasts just a few days. “Females in estrus make
these very low, long calls that
bulls home in on, because it’s such a rare event,”
O’Connell-Rodwell says. These
powerful estrus calls carry more than two miles in the air
and maybe accompanied by
long-distance seismic signals, she adds. Breeding herds also
use low-frequency
vocalizations to warn of predators. Adult bulls and cows
have no enemies, except for
humans, but young elephants are susceptible to attacks by
lions and hyenas. When a
predator appears, older members of the herd emit intense
warning calls that prompt the
rest of the herd to clump together for protection, then
flee. In 1994, O’Connell-Rodwell
recorded the dramatic cries of a breeding herd threatened by
lions at Mushara. “The
elephants got really scared, and the matriarch made these
very powerful warning calls,
and then the herd took off screaming and trumpeting,” she
recalls. “Since then, every
time we’ve played that particular call at the water hole, we
get the same response – the
elephants take off.”
G
Reacting to a warning call played in the air is one thing,
but could the elephants detect
calls transmitted only through the ground? To find out, the
research team in 2002
devised an experiment using electronic equipment that
allowed them to send signals
through the ground at Mushara. The results of our 2002 study
showed us that elephants
do indeed detect warning calls played through the ground,”
O’Connell-Rodwell
observes. “We expected them to clump up into tight groups
and leave the area, and
that’s in fact what they did. But since we only played back
one type of call, we couldn’t
really say whether they were interpreting it correctly.
Maybe they thought it was a
vehicle or something strange instead of a predator warning.”
H
An experiment last year was designed to solve that problem
by using three different
recordings – the 1994 warning call from Mushara, an
anti-predator call recorded by
scientist Joyce Poole in Kenya and an artificial warble
tone. Although still analyzing data
from this experiment, O’Connell-Rodwell is able to make a
few preliminary
observations: “The data I’ve seen so far suggest that the
elephants were responding as I
had expected. When the ’94 warning call was played back,
they tended to clump together
and leave the water hole sooner. But what’s really
interesting is that the unfamiliar antipredator
call from Kenya also caused them to clump up, get nervous
and aggressively
rumble – but they didn’t necessarily leave. I didn’t think
it was going to be that clear
cut.”
Questions 14-17
Complete the following summary of the paragraphs of Reading
Passage
Using NO MORE THAN THREE WORDS from the Reading
Passage for each
answer.
Write your answers in boxes 14-17 on your answer
sheet.
Questions 18-24
Complete the following summary of the paragraphs of Reading
Passage.
Using NO MORE THREE WORDS OR A NUMBER from the
Reading Passage for
each answer.
Write your answers in boxes 18-24 on your answer
sheet.
How the elephants sense these sound vibrations is still
unknown, but O’Connell-
Rodwell, a fresh graduate in entomology at the University of
Hawaii, proposes that the elephants are “listening” with their 18…………………..,
by two kinds of nerve endings – that responds to vibrations with both 19…………………..
frequency and slightly higher frequencies. O’Connell-Rodwell work is at the
combination of geophysics, neurophysiology and 20…………………….,” and it also
was the first to indicate that a large land animal also is sending and
receiving 21……………………., O’Connell-Rodwell noticed the freezing behavior
by putting a male planthopper communicative approach other than 22……………………….”
Scientists have determined that an elephant’s ability to communicate over long distances
is essential, especially, when elephant herds are finding a 23……………………..,
or are warning of predators. Finally, the results of our 2002 study showed us
that elephants can detect warning calls played through the 24……………………..”
Questions 25-26
Choose the correct letter, A, B, C or D.
Write your answers in boxes 25-26 on your answer
sheet.
25 According to the passage, it is determined that an
elephant need to communicate
over long distances for its survival
A When a threatening predator appears.
B When young elephants meet humans.
C When older members of the herd want to flee from
the group.
D When a male elephant is in estrus.
26 What is the author’s attitude toward the
experiment by using three different
recordings in the paragraph:
A the outcome is definitely out of the original
expectation
B the data cannot be very clearly obtained
C the result can be somewhat undecided or inaccurate
D the result can be unfamiliar to the public
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