They come out of the setting sun, flying low over suburban Australia in vast black squadrons armed with fruit-seeking sensors, razor sharp teeth and, on very rare occasions, a little-known virus that is potentially fatal to humans.
Parents take their children out to watch and tourists scramble for their cameras as the fruit bats, or flying foxes as they are also known, leave their colonies at dusk and cruise silently overhead in their thousands, bound for orchards, backyard fruit trees and sweet eucalyptus blossoms.
With wingspans of around three feet (one meter) and manes of orange fur, they make an impressive sight.
But a new outbreak of bat-borne Hendra virus has rattled residents of eastern Australia. Discovered near the Queensland state capital of Brisbane in 1994, four of the seven people ever to have contracted the disease have died.
It normally afflicts horses, 14 of which have died or been put down in Australia since June.
No people have died in the latest outbreak but this week's discovery of Hendra in a dog has scientists concerned that a more contagious version of the virus is loose.
And some politicians are so concerned they are discussing sending in choppers to bomb bat colonies around Brisbane with smoke canisters in the hope of moving them away from population centers.
Liberal National Party leader Campbell Newman says ground forces would then move in to destroy the bats' roosting trees so they wouldn't return. It's time to "get real," he said, according to The Courier-Mail newspaper.
"There needs to be a proper use of the tools available -- smoke bombs, noise and helicopters," he said.
"When the bats have been moved from the vegetation they've been roosting in in these urban areas, basically that vegetation should appropriately come down," he said.
Scientists and Queensland's Labor government have already dismissed the idea, saying it would only scatter the bats and potentially spread the virus further afield.
It would also increase the bats' stress levels, and research has shown that stressed bats are more likely to carry Hendra.
The virus is believed to spread to horses via fruit scraps dropped by the bats, or through water and food contaminated by bats' droppings.
Malaysia has imposed a ban on the import of horses from Australia as a precautionary measure following the outbreak.