Bright pink millipedes emerged in a forest during the rainy season in Thailand.

The aptly named 'shocking pink dragon millipedes' appeared in the lush forests of the Hup Pa Tat valley at the Tham Prathun Non-hunting Area in Uthai Thani province.

Tourists visiting the area on September 3 took close-up photos of the many-legged, spiny creatures seen crawling across limestone caves and leaf litter.

The arthropods' bright colours indicate its toxicity. It produces almond-scented hydrogen cyanide - a poisonous chemical asphyxiant used in fumigation, mining, and the production of plastics, pesticides, and synthetic fibres.

The millipedes can grow up to 1.2 inches long and occur in large numbers after rain. They were formally described in the Hup Pa Tat valley by scientists Henrik Enghoff, Chirasak Sutcharit, and Somsak Panha, in 2007.

Aside from the millipedes, the visitors also saw other wildlife like monkeys, Siamese fireback pheasants, rock doves, great mynas, and serows, on their guided tour of the area.

They trekked through the 165-foot-long 'Time Tunnel' cavern said to contain flora and fauna from prehistoric times.