A possible case of water-sharing in grey-headed flying-foxes during extreme heat

Abstract

Behavioural strategies used by wildlife to mitigate thermal stress are at the forefront of ecological research as the frequency, severity, and geographic range of extreme heat increase. On 27 January 2026, grey-headed flying-foxes (Pteropus poliocephalus) were monitored from the banks of the Yarra River in Melbourne, Victoria, Australia, where the maximum air temperature reached 40.7°C. An adult flying-fox belly-dipped into the river, saturating its ventral fur before landing in a tree overhanging the river; here it proceeded to drink the water off its saturated fur. This adult bat was joined by a smaller conspecific which licked the wetted bats fur for over a minute. This research note describes an apparent water-sharing behaviour and considers whether this interaction may represent a previously undescribed social mechanism that facilitates access to water during extreme heat, particularly for vulnerable individuals.