Caragh Threlfall haunts Sydney by night in search of tiny insect-eating bats to learn more about one of Earth's least-studied mammals.

Under cover of darkness, the 25 year-old UNSW PhD student searches tunnels, storm water drains and abandoned warehouses.

"Sydney is host to 20 species of insectivorous bats and nearly half this number are threatened, although nobody knows for sure why this is so," says Ms Threlfall, who says there are 1,000 known species of bats worldwide.

During warmer months when bats are most active, insectivorous bats can eat eight to ten times their body weight in insects in one night, making them a friend to farmers and other mozzie-swatting humans.

"There's some thought that black rats might be threatening insectivorous bats," she says, "because they're very agile climbers, and therefore capable of invading tree hollows and other places where bats roost."

Ms Threlfall is calling on Sydneysiders to alert her to bats in their local area.

"Habitat destruction, predation, poisoning and competition for roosting sites mean bats are being forced to find new and obscure places to call home."

Sydneysiders who know of bats in their area are asked to contact Caragh Threlfall at UNSW at

Media Contact: Dan Gaffney | 0411 156 015 |