An unpredictable, yet scorching and dry climate kept large, grass-eating dinosaurs out of the tropics for some 30 million years after they first appeared on Earth, a study out Monday found.

It has been a longstanding mystery: why did long-necked dinosaurs seem to avoid the tropics when there were many different types of them lived at different latitudes well north and south of the equator? There are fossil remains, however, of meat-eating dinosaurs in the tropics.

Europe's robot lab Philae has made followup contact with Earth more than a day after sending home its first message in nearly seven months since landing on a comet, its ground operators said Monday.

The lander reestablished contact early Monday morning GMT, and is now "completely awake", Jean-Yves Le Gall, president of the French CNES space agency told television station France 2.

A five-meter (16-foot) crocodile has put on a spectacular display for a passing tour boat, attacking and chomping on a smaller croc before plunging it into an unsurvivable "death roll".

British trainee guide Nikki Davies said one or two of the fearsome predators were usually spotted during cruises in the Kakadu region of northern Australia.

Europe's comet lander Philae has woken up overnight after a months-long sleep, hurtling towards the Sun in deep space, the president of France's CNES space agency said Sunday. 

"We received new signals from (Philae) for a period of two minutes, as well as 40 seconds worth of data," Jean-Yves Le Gall told Agence France Presse.

Six scientists who were living under a dome on the slopes of a dormant Hawaii volcano for eight months to simulate life on Mars have emerged from isolation.

The crew stepped outside the dome that's 8,000 feet (2,400 meters) up the slopes of Mauna Loa to feel fresh air on their skin Saturday. It was the first time they left without donning a space suit.

California announced Friday it was slapping water restrictions on some of the oldest water rights holders in the parched U.S. state, the first such measures in four decades.

The cuts by the western state, gripped by the fourth year of a punishing drought, will restrict water use by over 100 farmers and others with rights dating back to 1903.

South Korea's oldest nuclear reactor is expected to be shut down permanently in 2017 after growing safety concerns over the ageing facility.

A state energy committee has decided to urge the state-financed Korea Hydro and Nuclear Power Co. (KHNP) to close the Gori Reactor No.1 in the southern port of Busan.

Japan's government approved Friday a revised 30- to 40-year roadmap to clean up the wrecked Fukushima nuclear plant, but many questions remain.

The plan, endorsed by Cabinet members and officials, delays the start of a key initial step — the removal of spent fuel in storage pools at each of the three melted reactors — by up to three years due to earlier mishaps and safety problems at the plant.

British Nobel Prize-winning scientist Tim Hunt has resigned from his post at University College London over controversial comments he made about female scientists.

Hunt, who holds other posts, has apologized for causing offence after suggesting that female scientists could not take criticism without crying, and that relationships between men and women in the laboratory disrupted work.

Three astronauts landed in Kazakhstan on Thursday, safely returning to Earth after their flight back home was delayed for a month by a Russian rocket failure.

Russia's Anton Shkaplerov, Italy's Samantha Cristoforetti and Terry Virts of the United States landed on schedule on the steppes of Kazakhstan and appeared to be in good health.