The Fireflies That Flash Together
Along a river in Malaysia, thousands of fireflies sit in the mangrove trees and flash on and off, all at the same moment, like Christmas lights.
What was reported
On the banks of the Selangor River near Kampung Kuantan, fireflies gather at night in the berembang trees that line the water. Instead of flashing at random, whole trees of them blink in unison, several times a second, turning the riverbank into rows of pulsing lights.
For centuries, European travellers to South-East Asia wrote of trees that lit up as if by magic, and some scientists back home refused to believe it.
Explanations offered
The males flash together to attract females. Each firefly adjusts its rhythm slightly to match its neighbours until the whole group falls into step, a pattern scientists study to understand how synchronisation works in nature. Pollution and land clearing now threaten the colonies.
- When
- Every night
- Where
- Kuala Selangor, Selangor, Malaysia
- Witnesses
- Visitors on the Selangor River
- Status
- Explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
More from Malaysia