Thousands of bats flying out of a cave made a mesmerising snake-like formation across the sky.

Footage shows the swarm of winged mammals soaring in unison between rock formation's mouth in Phetchabun, Thailand on January 17.

The river of bats flowed for almost half an hour before all of them left the area.

Residents and tourists visited the spot across the Pha Thong Cave, anticipating to watch the creatures which didn't disappoint.

Sombat Sodwilai, 57, said: ‘The bats usually fly out of the cave in the evening during December.

‘They sometimes fly low and hit the electric wires. We don't know where they go but they might be looking for food together somewhere far.'

The villager added the bats eventually return just before the sun shines in the morning.

He said: ‘They come back at 5am and fly everywhere. This is a great place to watch them, everyone should visit.'

Village officer Patcharawalai Saitaisong said the population of bats has increased.

She said: ‘This had been happening for a long time, but we've seen more bats in the last two years.

‘They fly outside every night by the end of the year and continue for around a month.'

‘After that, they will not fly out of the cave until the end of next year.

‘Therefore, we wanted to turn the cave into a landmark to attract tourists.'

Apart from bats, there were a large Buddha image and sparkling stalagmites to be marvelled at the remote village.