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Toads able to detect earthquake days beforehand, study says
1. Toads may be able to detect earthquakes days before they hit, according
to a study which reveals how the creatures deserted their mating site before Italy's
L'Aquila quake last year. Toads may be able to detect imminent earthquakes,
according to scientists. The finding will add to the accounts through the
centuries where animals, from dogs to rats, snakes, and chickens, are said to
have behaved strangely before an earthquake.
2. In the study published today in the Journal
of Zoology, a colony of toads deserted their mating site three days before
an earthquake struck in L'Aquila - the epicenter was 74 kilometers from the area
where the animals had normally gathered. No toads returned to the site until 10
days later, after the last of the significant aftershocks had finished.
3. The discovery was made by accident by Rachel Grant,
a life scientist at the Open University. She was studying the effects of lunar
cycles on the toads' behavior and reproduction. "I was going out every
evening at dusk and counting how many toads were active and how many pairs
there were. Normally they arrive for breeding in early March and you get large
numbers of males at the breeding site. The females get paired fairly quickly. They
stay active and obvious around the breeding site until the spawning is over in
April or May." One day she noticed there were no toads. "Sometimes
during the breeding season you get a drop in numbers if there's been a very
cold night, but usually the day after, they come back again. It was very
unusual that there was none at all." There could be several mechanisms for
animals to sense the beginnings of an earthquake, wrote Grant in the Journal
of Zoology. They could detect seismic waves directly or ground tilt (which
can occur in the minutes before a quake). In addition, there might be anomalies
in the earth's magnetic field.
4. Looking for clues to explain the toads' behavior, Grant found that
scientists had noticed disruptions in the ionosphere, the uppermost
electromagnetic layer of the earth's atmosphere, at the time of the L'Aquila
earthquake, which the toads may have detected. Previous earthquakes have had
similar ionospheric disruptions associated with them. "I've spoken to
seismologists who said there were a lot of gases released before the
earthquake, a lot of charged particles. Toads and amphibians are very sensitive
to changes in environmental chemistry, and I think these gases and charged
particles could have been detected by the toads."
5. Previously, fish, rodents, and snakes have been anecdotally associated
with unusual behavior more than a week before an earthquake or at distances greater
than 50 kilometers. In 2003, Japanese doctor Kiyoshi Shimamura said that there
was a jump in dog bites and other dog-related complaints before and after earthquakes.
Before the 1995 earthquake in Kobe, a disaster that killed more than 6,000
people, he found that accounts of dogs barking "excessively" went up
by 18 percent on average in the months before the earthquake. Above the
epicenter on Awaji Island, there was a 60 percent increase in complaints
compared with a year earlier.
6. Grant's work is not the first time toads have been associated with
sensing the precursors of earthquakes. "In 2008, there was a big
earthquake in Szechuan province in China, and there was unusual migration of toads
seen," she said. "I'd like to study it further and look at animal
behavior in combination with seismological and geophysical precursors."
SOURCE: The GuardianFind and drag the number of the paragraph that each sentence summarizes.
1. Toads might have felt the variations in gases
in the earth's atmosphere. Blank 1 Вопрос 1paragraph 5
2. There have been many stories about the
changes in fish, snake, and rodent behavior before an earthquake or natural
disaster. Blank 2 Вопрос 1paragraph 2
3. Recent research shows that toads might be
able to predict earthquakes. Blank 3 Вопрос 1paragraph 4
4. Grant noticed the toads' change in behavior
while conducting an unrelated study. Blank 4 Вопрос 1paragraph 3
5. Others have noticed the change in toads'
behavior before an earthquake. Blank 5 Вопрос 1paragraph 6
6. Toads left their mating site before the L’Aquila
earthquake. Blank 6 Вопрос 1paragraph 1