Science News Digest
This is Sarah Long. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science.
Today we tell about a huge ancient crocodile. We tell about new drugs that can decrease kidney damage in people with diabetes. And we tell about decreasing numbers of orca whales in the northwest Pacific Ocean.
For the first time, scientists have reported details about a huge ancient animal that looked like a modern crocodile. A team led by University of Chicago researcher Paul Sereno calls the animal "SuperCroc." It was more than twelve meters long. It weighed as much as eight metric tons, more than some elephants. And it probably ate small dinosaurs. Mr. Sereno calls it one of the greatest crocodiles the world has ever seen.
Modern crocodiles and alligators are small compared to the ancient crocodile. For example, American alligators may reach a length of four-and-one-half meters and weigh six-hundred kilograms.
The ancient crocodile lived about one-hundred-ten-million years ago. SuperCroc lived in fresh-water rivers in Africa, unlike other crocodiles of the time that lived in salt-water oceans.
Scientists have known about the ancient creature for many years. French researchers found evidence of the animal in Nineteen-Sixty-Four. They gave it the scientific name Sarcosuchus imperator. But they did not find enough fossil remains to learn much about the animal and how it lived.
However, last year, the team led by Mr. Sereno found several head bones of the huge crocodile. They also found twenty tons of other fossils. Some of the remains were of other kinds of early crocodiles. They made the discoveries in the Sahara Desert area of Niger.
The researchers reported their discoveries last month on the Internet Web site of the journal Science. They also announced their findings at the National Geographic Society headquarters in Washington, D-C. The society helped pay for their research in Niger last year.
SuperCroc looks like a huge version of a modern crocodile. However, the researchers say members of the modern crocodile family did not develop from it. The modern group contains about twenty-three kinds of creatures including caimans and alligators.
Mr. Sereno's team members used a scientific method to estimate the size of SuperCroc. They measured its head bones. Other bones helped them learn more about the animal. For example, bony plates called scutes covered its body. The scutes have rings for each year of the animal's growth. Scientists say it became so huge because it grew every year during its fifty or sixty years of life.
SuperCroc also had a big growth of bone on the end of its nose. This growth may have helped the animal smell food. It also may have helped it make noises and calls. A modern crocodilian in India called a gharial has a similar growth.
The scientists made their discoveries at a place in the Sahara Desert called Gadoufaoua. The name means "the place where camels fear to go" in the language of the Taureg tribe. The area is extremely hot and dry. However, scientists have found many fossils there that represent important discoveries about ancient life.
Millions of years ago, Gadoufaoua had trees, plants and wide rivers. When animals died, the rivers covered their remains. Over the centuries, the drying rivers protected those remains.
Mr. Sereno's team began digging at Gadoufaoua in Nineteen-Ninety-Seven. At that time, the scientists were mainly studying dinosaur fossils. Then they found mouth bones almost two meters long. The bones contained about one-hundred teeth. They immediately recognized that these jaws did not belong to a dinosaur, but to an ancient crocodile.
Mr. Sereno said the ancient crocodile ate fish and turtles. It also hunted fiercely and skillfully for much bigger animals, like dinosaurs. Its eyes were set up in its skull. This meant it could look for animals with most of its body under the water. This helped SuperCroc surprise and kill dinosaurs.
The scientists say the ancient crocodile hid in the water when it was hungry. Then it quickly rose from the water and bit its target with its large teeth. On land, however, the size of SuperCroc probably prevented it from moving as fast.
Mr. Sereno's team also found remains of a dinosaur called a spinosaur in the same area. This animal was almost eleven meters long. The researchers believe SuperCroc and the spinosaur must have fought fiercely.
David Schwimmer of Columbus State University in Georgia praised the work of the Sereno team. Mr. Schwimmer is an expert about another ancient crocodile called Deinosuchus. This animal lived in North America. It was about the same size as SuperCroc and lived about the same time. But they were not closely related.
Mr. Schwimmer says conditions in those prehistoric days were very good for huge animals. The Earth was warm and green and full of living things.
You are listening to the Special English program SCIENCE IN THE NEWS on VOA. This is Bob Doughty with Sarah Long in Washington.
Recent studies show that several new drugs can greatly decrease kidney damage among people with the most common kind of diabetes. The drugs are called angiotensin receptor blocking agents.
The studies are the first to show that this kind of drug can block the hormone that causes kidney problems for people with Type Two diabetes. The studies were published in the New England Journal of Medicine. Kidney damage develops in about forty percent of all people with diabetes.
Barry Brenner is a kidney expert at Brigham and Women's Hospital in Boston, Massachusetts. He led one of the studies. Doctor Brenner says the new drugs will also reduce the cost of treating serious kidney problems related to adult diabetes.
Edmund Lewis also led one of the studies. He says all people with Type Two diabetes should be tested for kidney problems and should be treated immediately.
The number of people suffering diabetes has increased sharply in the United States in the past twenty years. Experts say about sixteen-million Americans have the disease. Many of these people also develop kidney failure. More than eighty-thousand people have had kidney replacement operations. Researchers say the new drugs could end the need for such operations within the next ten years.
Other studies have shown that similar drugs can help protect the kidneys in people with Type One diabetes. These people developed diabetes when they were children. Both kinds of drugs were first developed to treat high blood pressure.
Scientists are worried about orca whales in the waters of the northwest Pacific Ocean. These huge black and white sea creatures spend summers near the San Juan Islands near the state of Washington. They are called the southern population of orcas. Six years ago, ninety-nine orcas swam there. Today, only seventy-eight orcas survive. During the past year alone, seven whales died.
Orcas grow longer than nine meters and weigh up to nine metric tons. They are sometimes called killer whales. However, they are not especially aggressive.
Millions of healthy orcas live in the world. However, researchers say humans and a decreasing food supply are threatening the existence of the southern population of orcas. These whales live in three groups, called pods. Every orca has its own markings. So scientists can identify each individual orca.
Every May through October, visitors crowd into boats to follow the orcas. The whale-watching industry is worth tens of millions of dollars a year. However, scientists believe these whale-watching boats may be harming the orcas. The boats may be polluting the water. And the noise from the engines may be interfering with how orcas communicate with each other.
American government officials will decide next year if these orcas should be officially listed as in danger of disappearing from Earth.
This SCIENCE IN THE NEWS program was written by Jerilyn Watson and Paul Thompson. This is Bob Doughty. And this is Sarah Long. Join us again next week for more news about science in Special English on the Voice of America.