Douglas Gimesy's Image

The extreme heat of the Australian summer caused a group of grey-headed flying foxes to abandon their treetop roosts and collect en masse around a tree trunk, in the hope of escaping the heat of the day.

Sadly, this 'clumping' behaviour only exacerbates their heat stress as the bats crowd together, getting hotter. Eventually one may fall, knocking others down, creating a pile at the bottom of the tree. Unable to move, the bats get even hotter and can suffocate each other.

Doug notes how, at this colony at Yarra Bend, 'hundreds piled up at the base of trees, dead or dying from exhaustion or suffocation'.

Local rescuers tried to save as many bats as possible by spraying them with water to cool down, however more than 4,500 are estimated to have died during this heat stress event - about 10% of the colony.

Large fruit bats like these play an important role in maintaining the health and biodiversity of forest habitats up and down the Australian coast through tree pollination and seed dispersal. They are increasingly facing catastrophic heat stress events which threaten the survival of the species.

How you can help

• If you see a group of flying foxes 'clumping', contact the local wildlife trust or other nature organisation and alert them to the situation.
• Talk to your friends and family about the benefits that fruit bats have to the environment
• Global warming is causing extreme temperatures all over the world, support initiatives that take action to reduce emissions and global heating.