This is SCIENCE IN THE NEWS in VOA Special
English. I'm Barbara Klein.
I'm Bob Doughty. This week, we will tell
about evidence of early human ancestors.
We also will tell about the health effects of hopeful feelings. And, we will tell about disappearing bat
populations in the northeastern United States.
An international research
team has discovered markings made by the ancestors of modern human beings more
than one million years ago. The discovery
is exciting because it shows the shape of the feet and walking method of the
Professor Jack Harris led the researchers and students who uncovered the marks
during three years of digging. They
found the ancient footprints near the village of Ileret in northern Kenya. A report about their findings was published
last month in Science magazine.
Early humans made the footprints as they walked on
volcanic ash and soil that turned to rock over time. The team found two sets of prints in separate
levels of rock that are about one million five hundred thousand years old.
scientists say the prints were left by one of two human ancestors: either Homo
erectus or Homo ergaster. However, many
experts do not recognize a difference between the two. Homo erectus is the more commonly used name.
Surprisingly, the footprints look much like those you
would find on a sandy coastline today. In their report, the team said the discovery provides the oldest
evidence of a foot structure that is generally the same as a modern human's.
show how the big toe of Homo erectus is close to the other toes. In earlier species, the big toe is separated
widely from the other toes -- as in the foot structure of apes. No Homo erectus foot bones have ever been
found. This makes the well-preserved
footprints especially valuable.
Scientists have also learned how Homo erectus walked
from the prints. Researcher Matthew
Bennett of Bournemouth University used laser technology to make digital images
of the footprints. These images suggest
that Homo erectus walked by touching the ground first with the back of the foot
and pushing off with the front -- just as we do.
researchers could even estimate the height of the ancient individuals. One was only about a meter tall. It is believed to have been a child. The others were about the average height of
modern human adults.
findings provide more evidence that human ancestors were able to travel long
distances. Homo erectus may have left
Africa for other parts of the world as early as one million eight hundred years
This is only the second
time that early human footprints have been found. In nineteen seventy-eight, British
anthropologist Mary Leaky discovered the prints of a possible human ancestor at
Laetoli, Tanzania. They belonged to
Australopithicus afarensis, a much earlier and smaller human-like creature that
walked on two feet.
Harris says his team not only found footprints, but also many animal tracks in
the rock. These include markings of
hoofed animals that Homo erectus may have hunted for food. Other tracks belonged to meat-eaters. Such creatures were competitors or even
threats to the early humans.
The footprints found in Kenya have let scientists step
back in time to find new details about our distant ancestors and their
An American study has shown that being hopeful about future
events might help you stay healthy and live longer. The study found links between people's
beliefs and their risks of cancer-related death, heart disease and early death.
studied one hundred thousand women during an eight-year period, beginning in
nineteen ninety-four. All of the women
were fifty years of age or older. The
study was part of the Women's Health Initiative, a continuing study organized
by the National Institutes of Health. The findings were presented earlier this month at a meeting of the
American Psychosomatic Society.
the study, the women were asked questions that measured their beliefs or ideas about
the future. The researchers attempted to
identify each woman's personality eight years after gathering the
study found that the hopeful individuals were fourteen percent less likely than
other women to have died from any cause. The hopeful women were also thirty percent less likely to have died from
heart disease after the eight years.
Trindle was the lead writer of the report. She is an assistant professor of medicine at the University of Pittsburgh
in Pennsylvania. She says the study
confirms earlier research that also linked optimistic feelings to longer
life. However, this study is different
from earlier research on the subject.
researchers also gathered information about people's education, financial
earnings, physical activity and use of alcoholic drinks or cigarettes. Independent of those things, the findings
still showed that optimists had less of a chance of dying during the eight-year
Some women who answered the study's questions were
found to be cynically hostile, or highly untrusting of others. These women were sixteen percent more likely
to die than the others. They also were
twenty-three percent more likely to die of cancer.
study also found that women who were not optimistic were more likely to smoke,
have high blood pressure or diabetes.
They were also more likely not to exercise.
Tindle says the study did not confirm whether optimism leads to healthier
choices, or if it actually affected a person's physical health. She says the study does not prove that
negative emotions or distrust lead to bad health effects, and shorter
life. Yet there does appear to be a link
between the two. More research is needed
to discover the exact reasons for the findings.
In recent years, biologists have
observed a sharp drop in bat populations in the northeastern United
States. The biologists believe the drop
has resulted from a mysterious sickness called white nose syndrome.
Little is known about the sickness. It is called white nose syndrome because of a
white-colored fungus found on the faces of affected bats. The fungus seems to grow in cold weather. The affected animals were first observed in
two thousand seven in New York State.
Scientists believe the disease causes bats to awaken early
from their hibernation or yearly rest period.
The scientists say the bats then leave their resting places in search of
food during the winter when the insects they eat are not available. Without a food supply, the bats starve to
Wildlife officials say white nose syndrome is
not a direct threat to other animals or human beings. However, the bats' continuing disappearance
could have a far-reaching effect on the environment.
Bats have survived for about fifty million years. They eat large amounts of insects, up to
twenty-five percent of their body weight in one night's feeding. If fewer bats are available to eat the
insects, farmers will have to use more insect-killing chemical products to
protect their crops. Diseases that are
spread by insects could also become more common.
of white nose syndrome have been confirmed in New York, New Jersey,
Connecticut, Vermont, Massachusetts and Pennsylvania. It is difficult for scientists to know the
exact number of bats that have died as a result of white nose syndrome. However, some estimate that hundreds of
thousands of bats have already disappeared.
United States Geological Survey says the disease has affected six bat
species. They include little brown bats,
northern bats, tricolored bats, Indiana
bats, small-footed myotis and big brown bats.
are currently studying possible ways to keep the disease from spreading. Tests are needed to guarantee a plan that
will be effective.
SCIENCE IN THE NEWS program was written by Mario Ritter and Brianna Blake, who
was also our producer. I'm Bob Doughty.
I'm Barbara Klein. Read and listen to
our programs at voaspecialenglish.com. Join us again next week for more news about science in Special English
on the Voice of America.
Correction: This story should have said that Homo erectus may have left
Africa as early as one million eight hundred thousand years
ago, not one million eight hundred years ago.