The most common species of ant found on the pavements of New York City and in cities around the world has a taste for human food — more than other ant species found primarily in parks and other green spaces, a study says.

"The ants that live alongside us in our cities also seem to be those same species that can eat the same food that we do, and do so the most," said Clint Penick, a post-doctoral fellow at North Carolina State University and lead researcher of the study published Wednesday in the scientific journal Proceedings of the Royal Society B.

Europe's pioneering probe Rosetta battled breakdowns with navigation and communication with Earth after it ran into blasts of dust and gas from the comet it is tracking, mission control said Thursday.

Swooping close to Comet 67P/Churyumov-Gerasimenko, Rosetta "experienced significant difficulties" last weekend and had to go into safe mode, the European Space Agency (ESA) said.

Scientists in Britain said Thursday they had developed the first perfume which smells better the more you sweat and reduces body odour.

Researchers at Queen's University Belfast said in a statement that the new perfume "releases more of its aroma when it comes into contact with moisture".

A group of researchers say polar bears forced off melting sea ice will not find enough food to replace their current diet of fat-laden marine mammals such as seals, a conclusion that contradicts studies indicating that bears may be benefiting from bird eggs, berries and other land food sources.

Few bears are using land food and what they find can't replace lipid-rich ringed or bearded seals, said Karyn Rode, a U.S. Geological Survey research wildlife biologist and lead author of the review paper published Wednesday in the journal, Frontiers in Ecology and the Environment.

Engineers have come up with a motor-free device to make walking more efficient and easier — something scientists once thought couldn't be done.

The prototype exoskeleton boot runs from just below the knee to the ankle, and when you strap on a pair, you can reduce the energy it takes to walk by 7 percent. That means you won't burn as many calories.

The eyes of 30-odd uniformed schoolchildren light up at the sight of three magnificent lions brought to Abidjan zoo to replace the big cats that starved to death during post-election violence in 2010-2011.

For many Ivorians, the arrival this month of the South African felines -- two lionesses and a male -- shows that the country really is managing to get back on its feet.

Cancer-fighting pink pineapples, heart-healthy purple tomatoes and less fatty vegetable oils may someday be on grocery shelves alongside more traditional products.

These genetically engineered foods could receive government approval in the coming years, following the OK given recently given to apples that don't brown and potatoes that don't bruise.

Russia, moving ahead of a deadline for submitting pledges to tackle climate change, said Tuesday it could cut its greenhouse-gas emissions by up to 30 percent compared to 1990 levels, subject to conditions.

In a roster of commitments on the UN Framework Convention on Climate Change (UNFCCC) website, Russia announced that "limiting anthropogenic [man-made] greenhouse gases in Russia to 70-75% of 1990 levels by the year 2030 might be a long-term indicator."

Latin America spends billions of dollars subsidizing fossil fuels each year, but also has some of the world's largest renewable power programs, highlighting the energy-hungry region's divisions as it charts its future.

Exhibit A is Venezuela, estimated to have the biggest oil reserves on Earth, where drivers can fill their gas tanks for about $1.

Boys and girls are equal in number at conception, but more female fetuses die during pregnancy, leading to a slightly higher number of males being born, researchers said Monday.

The study in the Proceedings of the National Academy of Sciences is based on the largest dataset ever analyzed in the search to explain what is known as the human sex ratio, which has been poorly understood until now.