Astronauts chosen for a manned mission to Mars could be in serious trouble if their sleep patterns are disrupted on the lengthy journey, a 520 day simulation has found.

"The success of human interplanetary spaceflight, which is anticipated to be in this century, will depend on the ability of astronauts to remain confined and isolated from Earth much longer than previous missions or simulations," said David Dinges of the University of Pennsylvania, who co-authored the sleep study.

Breeding season is underway for the endangered tortoises of Ecuador's Galapagos Islands, whose mating and nesting habits are carefully watched by wildlife specialists hoping to save them from extinction.

Nesting began last month at Galapagos National Park and will be monitored through June to determine how many female tortoises have prepared nests and how many hatchlings are likely to emerge.

Japan will launch a survey of its Pacific seabed, an official said Thursday, hoping to find rare earth deposits large enough to supply its high-tech industries and reduce its dependence on China.

Researchers from the Japan Agency for Marine-Earth Science and Technology will start the probe from January 21 on the seabed near Minamitorishima island, some 2,000 kilometers (1,250 miles) southeast of Tokyo, he said.

Astronauts chosen for a manned mission to Mars could be in serious trouble if their sleep patterns are disrupted on the lengthy journey, a 520 day simulation has found.

"The success of human interplanetary spaceflight, which is anticipated to be in this century, will depend on the ability of astronauts to remain confined and isolated from Earth much longer than previous missions or simulations," said David Dinges of the University of Pennsylvania, who co-authored the sleep study.

Record temperatures across southern Australia cooled Wednesday, reducing the danger from scores of raging wildfires but likely bringing only a brief reprieve from the summer's extreme heat and fire risk.

Australia had its hottest day on record Monday with a nationwide average of 40.33 degrees Celsius (104.59 degrees Fahrenheit), narrowly breaking a 1972 record of 40.17 C (104.31 F). Tuesday was the third hottest day at 40.11 C (104.20 F). Four of Australia's hottest 10 days on record have been in 2013.

Animal rights activists claimed a major victory Tuesday in their campaign to stop global airlines from transporting monkeys for use in laboratory experiments.

In a statement, People for the Ethical Treatment of Animals (PETA) said it had been told by United Airlines that it would ban the transport of primates to laboratories under the terms of its cargo policy.

Getting pruney fingers from soaking in the bath is an evolutionary advantage, for it helps us get a better grip on objects under water, scientists suggested on Wednesday.

Digit puckering was long thought to be caused by a swelling of the outer layers of skin on the fingertips and toes, but recent research showed it was actually a nervous system response to immersion in water.

The United States of America set an off-the-charts heat record in 2012.

A brutal combination of a widespread drought and a mostly absent winter pushed the average annual U.S. temperature last year up to 55.32 degrees Fahrenheit (13 Celsius), the government announced Tuesday. That's a full degree Fahrenheit (0.6 degrees Celsius) warmer than the old record set in 1998.

Hideaki Kato discovered his true identity by accident.

During his medical training a decade ago, the now 39-year-old Japanese doctor was performing blood tests on family members when he learned something startling: his dad was not his biological father.

The US Supreme Court declined Monday to enter the emotionally-charged debate over stem cell research, refusing to hear an appeal centered on the issue of federal government funding.

The top US court did not give a reason for its decision, which ends the long judicial saga over President Barack Obama's 2009 executive order lifting restrictions on financing imposed by his predecessor George W. Bush.