Dolphins stranded on Japan beach

Nearly 150 melon-headed whales, a species of dolphin, have become stranded on a beach in Japan.

They were found along a 4km (2.5 mile) stretch of beach in the Ibaraki prefecture, north-east of Tokyo.

Efforts are under way to try to rescue the animals.

"We see one or two whales washing ashore a year, but this may be the first time we have found over 100 of them on a beach," a coastguard official told the AFP news agency.

About 50 animals of the same species beached themselves in a similar area in 2011.

The reason for the beaching is unclear, but researchers from the National Museum of Nature and Science travelled to the beach to investigate.