"Elephant Communication"
Reading Passage 3
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 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 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 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 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.”
Elephant Communication
Reading Passage Questions
Questions 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.
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)……………………..”
Questions 39-40
Choose the correct letter, A, B, C or D.
39. 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.
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
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