A photo of tiny creatures nestled inside a tunnel in Australia left people wondering as to what they were called.

The image was shared by Queensland's Department of Transport and Main Roads on Facebook, asking users to identify the mysterious creatures.

"Don't freak out — they heard you coming a mile off! What exactly are we looking at here?" the department asked about the creatures that were inside a tunnel on the Brisbane Valley Rail Trail.

"These tiny locals were spotted hanging out in the heritage-listed Yimbun Tunnel," the department said.

As users were unable to identify them, the department gave out some hints as help.

"You might find them hanging upside down," the department hinted. "This species only eat insects unlike our flying fox friends."

Later, the department wrote the creatures were micro bats, the largest species of which only grow to a body length of approximately 11 cm.

"They will keep to themselves in their roosts, some will stay still if approached, while others will try to crawl or fly away from you," the department wrote, adding if anyone comes across them, its better to leave them alone.

One user said that these creatures were harmless: "We had them at my mum's old house they r harmless we used to stand in their flight path and it never worried them."

The micro bats mostly eat insects. However, one Australian species (the ghost bat) is also known to eat frogs, birds, lizards and other mammals, Queensland's Department of Environment and Science said on its website. Micro bats are found inside tree hollows or caves. Some also sleep under barks or in the discarded nests of certain birds.

Australia has approximately 70 species of bats, with 43 species identified as being locally or nationally threatened, the department said. Of these, 35 of the species are micro bats. The department also said if bitten or scratched by a bat, it is necessary to get a prompt treatment. Do not scrub the wound and wash it gently before applying an antiseptic.

Bats fly in a cave in Herzliya, near Tel Aviv, July 31, 2012. REUTERS/Nir Elias