Man's best friend has not been around for nearly as long as thought, according to a study Thursday that brings the emergence of modern dogs forward by some 15,000 years.

The finding follows the reclassification of two fossil skulls, one more than 30,000 years old, that were the basis for dating dog domestication to a long-gone era when early humans were still roaming hunter-gatherers.

A study involving 20,000 children in China said Thursday that poor kids are far less likely to be nearsighted than their wealthier peers.

Nearsightedness, or myopia, was twice as prevalent in the middle-income province of Shaanxi -- where students have greater access to books that require close-up focusing -- compared to the poorer neighboring province of Gansu, said research in Ophthalmology, the journal of the American Academy of Ophthalmology.

The French hosts of a U.N. climate summit later this year insisted Thursday that combatting global warming would not undermine efforts to fight poverty as they lobbied for India's support in cutting emissions.  

Speaking in New Delhi, France's Foreign Minister Laurent Fabius said he was confident India would play a lead role in efforts to create a low carbon economy, adding to pressure on the right-wing government after similar calls last week from U.S. President Barack Obama. 

The world's mightiest waterway, the Amazon River, is threatened by the most diminutive of foes — a tiny mussel invading from China.

Since hitching its way to South America in the early 1990s, the golden mussel has claimed new territory at alarming speeds, plowing through indigenous flora and fauna as it has spread to waters in five countries. Now, scientists fear the invasive species could make a jump into the Amazon, threatening one of the world's unique ecological systems.

India's government on Tuesday defended its efforts to combat climate change after U.S. President Barack Obama urged the country to reduce its dependence on fossil fuels.

Environment Minister Prakash Javadekar said the government was already turning words into action on clean energy with efforts that include increasing solar power across the country.

Scientists said Wednesday they had amassed the first evidence to back theories that people fall into two broad categories -- promiscuity or faithfulness -- when it comes to sex.

Why humans seem to be an exception among mammals on the matter of sexual relationships has long been a puzzle.

Soaring demand for tiger parts in China has emptied Asia's forests, frustrating efforts to protect the big cats, wildlife experts said as an anti-poaching conference opened in Kathmandu Monday.

Around 100 experts, government and law enforcement officials from 13 nations are attending the five-day summit, co-hosted by Nepal and conservation group WWF to hammer out a regional plan to fight poaching.

Flying in a V-formation is toughest for the leader, and migrating birds compensate by taking turns so that no one gets exhausted, international researchers said Monday.

The authors of the study in the Proceedings of the National Academy of Sciences, a U.S. peer-reviewed journal, described the discovery as the "first convincing evidence for 'turn taking' reciprocal cooperative behavior in birds."

Mercury levels are rising in Hawaiian yellowfin tuna, often marketed as ahi, at a rate of nearly four percent a year as the oceans absorb the pollutant from the air, researchers said Monday.

Coal-fired power plants and artisanal gold mining operations produce mercury, a potent toxin that makes its way into the world's water and poses a health risk to people who eat certain fish.

The only thing interrupting one of New Mexico's most remote stretches of desert is a pristine runway where Virgin Galactic plans one day to launch the world's first commercial space-line.

But the runway has seen little use. No roar of jet engines. Just delayed promises of shuttling passengers to the edges of Earth.