Thousands of caterpillars emerged after heavy rain to invade houses and public spaces in northern Thailand.

Hordes of the bugs appeared in villagers' houses in Chiang Mai province on May 24. Skin-crawling footage shows how the creatures squirmed as they covered large swathes of ground, climbed on walls and feasted on damp foliage.

Phawit Boonchala, Deputy Chief Executive of the San Phi Sue Subdistrict Administrative Organization, as well as health and environment officials, inspected the area after receiving numerous complaints from the townsfolk, who were worried the insects might pose harm to their pets and children.

The locals said it was the first they had seen such a massive swarm of caterpillars.

Authorities concluded that the invasion was caused by the recent downpour, which created a moist environment in which the caterpillars could thrive.

They said the animals liked to feed on detritus, so villagers were advised to clean their gardens and homes. They also sprayed insecticide and urged residents to use mothballs as an additional deterrent.

Further inspections will be conducted in the following days, officials said.

Thailand and other countries in Southeast Asia such as Malaysia, Indonesia and the Philippines are experiencing their tropical monsoon rainy season, which lasts until October or November.

Soaring temperatures reaching 35 degrees Celsius are often followed by powerful tropical storms with thunder, lightning, rain and flash floods.