Table of Contents
Elephant communication
Passage
A. 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. As 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, but 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 idbrations and may do the same in elephants.
C. But other aspects of elephant anatomy also support that ability. First, then 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. How 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 then 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 white-lipped 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 is 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 play back 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 nestrus 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 may be 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 lee.
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 hi 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 like 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 anti-predator 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
Questions 28-31
Summary
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 28-31 on your answer sheet.
Question 32-38
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 32-38 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 32…………., by two kinds of nerve endings—that responds to vibrations with both 33 ………….frequency and slightly higher frequencies, o’Connell Rodwell work is at the combination of geophysics, neurophysiology and 34 ………….and it also was the first to indicate that a large land animal also is sending and receiving 35 ………….,. O’Connell-Rodwell noticed the freezing behavior by putting a male planthopper communicative approach other than 36………… Scientists have determined that an elephant’s ability to communicate over long distances is essential, especially, when elephant herds are finding a 37…………., or are warning of predators. Finally, the results of our 2002 study showed US that elephants can detect warning calls played through the 38………….”
Question 39-40
Choose the correct letter. A, B, c or D. Write your answers in boxes 39-40 on your answer sheet.
39. According 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.
40. 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 can not be very clearly obtained
C. the result can be somewhat undecided or inaccurate
D. the result can be unfamiliar to the public
Answers
Below are the answers, key words, synonyms and full explanations for the IELTS Reading passage Elephant Communication (Passage 3, Questions 28–40).
Questions 28–31: Diagram Labelling — parts of the elephant that receive ground vibrations (NO MORE THAN TWO WORDS)
28. ______ bone (in the inner ear)
Answer: hammer
Key words: The hammer bone of the elephant’s inner ear is proportionally very large for a mammal … typical for animals that use vibrational signals
Synonyms: ______ bone in the inner ear = the hammer bone, large and suited to vibrational signals = “The hammer bone of the elephant’s inner ear is proportionally very large for a mammal, but typical for animals that use vibrational signals”
Explanation: The inner-ear bone that may sense seismic sound is the hammer bone → hammer.
29. the ______ (receives ground vibrations)
Answer: body
Key words: their enormous bodies … provide ideal frames for receiving ground vibrations and conducting them to the inner ear
Synonyms: the ______ receives ground vibrations = the enormous body is an ideal frame for receiving them = “their enormous bodies, which allow them to generate low-frequency sounds … provide ideal frames for receiving ground vibrations and conducting them to the inner ear”
Explanation: The elephant’s massive body acts as a frame that receives ground vibrations → body.
30. fatty ______ (under the toe bones)
Answer: pad
Key words: the elephant’s toe bones rest on a fatty pad that might help focus vibrations from the ground into the bone
Synonyms: fatty ______ under the toe bones = a fatty pad focusing ground vibrations into the bone = “the elephant’s toe bones rest on a fatty pad that might help focus vibrations from the ground into the bone”
Explanation: The toe bones sit on a fatty pad that focuses vibrations → pad.
31. ______ (in the front of the skull)
Answer: sinus cavities
Key words: The front of the skull is riddled with sinus cavities that may function as resonating chambers for vibrations from the ground
Synonyms: ______ in the front of the skull = sinus cavities acting as resonating chambers = “The front of the skull is riddled with sinus cavities that may function as resonating chambers for vibrations from the ground”
Explanation: The skull’s sinus cavities may resonate with ground vibrations → sinus cavities.
Questions 32–38: Summary Completion (NO MORE THAN THREE WORDS OR A NUMBER)
32. the elephants are “listening” with their ______
Answer: trunks and feet
Key words: the pachyderms are “listening” with their trunks and feet
Synonyms: listening with their ______ = listening with their trunks and feet = “O’Connell Rodwell … suspects the pachyderms are ‘listening’ with their trunks and feet”
Explanation: She thinks elephants sense the vibrations through their trunks and feet → trunks and feet.
33. nerve endings that respond to both ______ frequency and slightly higher frequencies
Answer: infrasonic
Key words: one that detects infrasonic vibrations and another that responds to vibrations with slightly higher frequencies
Synonyms: both ______ frequency and slightly higher = one nerve type for infrasonic vibrations, one for higher = “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”
Explanation: One nerve type detects infrasonic (very low) vibrations → infrasonic.
34. the combination of geophysics, neurophysiology and ______
Answer: ecology
Key words: Our work is really at the interface of geophysics, neurophysiology and ecology
Synonyms: geophysics, neurophysiology and ______ = ecology = “Our work is really at the interface of geophysics, neurophysiology and ecology”
Explanation: The third field named is ecology → ecology.
35. a large land animal also is sending and receiving ______
Answer: seismic messages
Key words: the first to suggest that a large land animal also is sending and receiving seismic messages
Synonyms: sending and receiving ______ = sending and receiving seismic messages = “O’Connell Rodwell was the first to suggest that a large land animal also is sending and receiving seismic messages”
Explanation: The large land animal sends and receives seismic messages → seismic messages.
36. other communicative approach besides ______
Answer: acoustic communication
Key words: maybe there’s something else going on other than acoustic communication
Synonyms: approach other than ______ = something other than acoustic communication = “maybe there’s something else going on other than acoustic communication”
Explanation: The planthopper behaviour hinted at communication besides acoustic communication → acoustic communication.
37. when elephant herds are finding a ______, or warning of predators
Answer: mate
Key words: The difficulty of finding a mate in this vast wilderness
Synonyms: finding a ______ = finding a mate = “The difficulty of finding a mate in this vast wilderness is compounded by … elephant reproductive biology”
Explanation: Long-distance communication matters for finding a mate → mate.
38. elephants can detect warning calls played through the ______
Answer: ground
Key words: elephants do indeed detect warning calls played through the ground
Synonyms: warning calls played through the ______ = through the ground = “The results of our 2002 study showed us that elephants do indeed detect warning calls played through the ground”
Explanation: The 2002 study showed elephants detect calls sent through the ground → ground.
Questions 39–40: Multiple Choice
39. According to the passage, an elephant needs to communicate over long distances for its survival
Answer: A (when a threatening predator appears)
Key words: Breeding herds also use low-frequency vocalizations to warn of predators … older members of the herd emit intense warning calls
Synonyms: for survival when a predator appears = herds use low-frequency calls to warn of predators = “Breeding herds also use low-frequency vocalizations to warn of predators … When a predator appears, older members of the herd emit intense warning calls”
Explanation: Long-distance calls are vital for survival to warn the herd when a predator appears → A.
40. What is the author’s attitude toward the experiment using three different recordings?
Answer: C (the result can be somewhat undecided or inaccurate)
Key words: the unfamiliar anti-predator call from Kenya also caused them to clump up … but they didn’t necessarily leave. I didn’t think it was going to be that clear cut
Synonyms: somewhat undecided/inconclusive = the results were not that clear-cut = “the unfamiliar anti-predator call … 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”
Explanation: The mixed responses show the results are not clear-cut, i.e. somewhat inconclusive → C.
Answer Key (Quick Reference)
| Q | Answer | Q | Answer |
|---|---|---|---|
| 28 | hammer | 35 | seismic messages |
| 29 | body | 36 | acoustic communication |
| 30 | pad | 37 | mate |
| 31 | sinus cavities | 38 | ground |
| 32 | trunks and feet | 39 | A |
| 33 | infrasonic | 40 | C |
| 34 | ecology |
