Long-necked plant-grazing dinosaurs that roamed the Earth 150 million years ago evolved a nifty way of fixing broken teeth. They just grew new ones, said a U.S. study Wednesday.

Scientists analyzed the fossils of two of the largest herbivores known to have lived in North America -- Diplodocus and Camarasaurus -- and found they grew fresh smiles every six weeks or so.

A strange glow in space has provided fresh evidence that all the gold on Earth was forged from ancient collisions of dead stars, researchers reported Wednesday.

Astronomers have long known that fusion reactions in the cores of stars create lighter elements such as carbon and oxygen, but such reactions can't produce heavier elements like gold.

Australia pledged another Aus$5 million (U.S.$4.6 million) to the fight against a predatory starfish devastating the iconic Great Barrier Reef Thursday, revealing 100,000 of the creatures had been wiped out so far.

Environment Minister Mark Butler said the new funding, on top of Aus$2.53 million already pledged, would support a program of culling the coral-eating crown-of-thorns starfish, which is naturally-occurring but has proliferated due to pollution and run-off.

A giant panda gave birth to twins at an American zoo this week -- the first panda double birth in the U.S. in 26 years.

Mama Lun Lun and her cubs, which were delivered Monday, are doing well, according to Zoo Atlanta in the southern state of Georgia.

Medical research that uses animals to test therapies for human brain disorders is often biased, claiming positive results and then failing in human trials, U.S. researchers said Tuesday.

The findings by John Ioannidis and colleagues at Stanford University could help explain why many treatments that appear to work in animals do not succeed in humans.

Palaeontologists in Utah on Wednesday said they had found the fossil of a strange horned dinosaur which roamed an island continent known as Laramidia.

Dubbed Nasutoceratops titusi, the creature lived during the Late Cretaceous about 76 million years ago.

U.S. Secretary of State John Kerry vowed Wednesday to keep up the battle to set up a sanctuary to protect the unique marine ecosystem in parts of the Antarctic.

And he voiced "regret" that attempts to create the world's largest ocean sanctuary in the Ross Sea were blocked, with environmental groups accusing Russia of raising objections to the move.

British scientists on Tuesday reported they had harnessed the power of urine and were able to charge a mobile phone with enough electricity to send texts and surf the internet.

Researchers from the University of Bristol and Bristol Robotics Laboratory in south west England said they had created a fuel cell that uses bacteria to break down urine to generate electricity, in a study published in the Royal Society of Chemistry journal Physical Chemistry Chemical Physics.

The fearsome bite of a hungry Tyrannosaurus rex left behind new evidence that the famous beast hunted for food and wasn't just a scavenger.

Researchers found a part of a T. rex tooth wedged between two tailbones of a duckbill dinosaur unearthed in northwestern South Dakota. The tooth was partially enclosed by regrown bone, indicating the smaller duckbill had escaped from the T. rex and lived for months or years afterward.

A tiny new moon has been spotted circling Neptune -- the 14th known to be orbiting the faraway planet, the US space agency said on Monday.

The moon is the smallest ever glimpsed around Neptune and measures just about 12 miles (19 kilometers) across, based on observations from the Hubble Space telescope, NASA said.