Which native Australian animal looks like a bat, sounds like a bat, but has a tiny body the size of a mouse?

Microbats, measuring 4 to 16 centimetres, make up one-fifth of all Australian mammals.

They live in the bush, in floodplains, and could be hunting for insects in your backyard.

A survey of mammals in the Mallee bush in north-west Victoria found 14 different species of microbat, weighing between 3 and 30 grams.

Microbats belong to the family order called Microchiroptera, meaning 'little hand-wing'.

Around 70 per cent of bats are microbats, and there are more than 60 different types.

Unmatched biodiversity

The Mallee Catchment Management Authority (Mallee CMA) studies microbats as well as other species in Victoria.

Researchers there cover a region of 3.9 million hectares, about one-fifth of Victoria, the largest catchment area in the state.

Community engagement and education officer for Mallee CMA, Susan Saris, said the biodiversity of microbats in the Mallee was unprecedented.

"That sort of diversity we don't see with any other mammals in the bush," she said.

"So that is amazing, and yet people don't even realise they live there."

Gould's wattled bat, a species commonly found in north-west Victoria. ( Supplied: Alex Holmes )

In early December, Mallee CMA held a public nocturnal tour of Merbein Common to look for microbats.

More than 50 people came out to hear about the little bats, learn about their habitat, and hear their usually silent shrieks using a bat-detecting app.

"These little guys, they're just hanging out doing their own thing and you've got all this species biodiversity happening and you don't even realise," Ms Saris said.

Microbats: The insect terminators

Microbats are nocturnal and rely on echolocation to find their prey in the dark.

During summer, microbats go into a feeding frenzy as they fatten up on insects to see them through the coming winter.

"All they're doing is getting out there for a feed, that's their big thing, getting out looking for insects," Ms Saris said.

Microbats have been described by enthusiasts as nature's pest control, for their diet of pest insects.

They love to gorge themselves on grain weevils, grub moths, mosquitos, beetles, and flying termites.

Corben's long-eared bat

Corben's long-eared bat is endangered and likes big open forest areas, such as Hattah in north-west Victoria. ( Supplied: Alex Holmes )

One of the key species in the Mallee region is the Corben's long-eared bat, which is federally listed and endangered.

Zoologist Alex Holmes manages the Mildura GHD office, which contracts scientists for mammal research in the Mallee.

Mr Holmes said the Corben's long-eared bat was of great interest both in Victoria and New South Wales.

"That species is threatened, so at the national level it's vulnerable to extinction," he said.

"It likes really large areas of habitat. Hattah is one area where they're known from, and they've been studied down there — anywhere where there's big large tracks of Bullah Ropsewood and Mallee habitat," he said.

For a microbat, Mr Holmes said they were quite large.

"We did trap a female last year that was 19 grams," he said.

In the broader Mallee district there have been up to 18 species of bats recorded.

"There's a couple of species like the lesser long-eared bat and the Gould's wattled bat — those two species are quite common in and around Mildura," Mr Holmes said.

Citizen science: Track your own microbats

The Mallee CMA said more information on the locations of microbats would be useful for further conservation efforts.

If you're interested, you can borrow what's called an 'anabat' to use at home.

"I'm really hoping to get people excited to borrow an anabat and go out there and collect some data for us," Ms Saris said.

"Tie it to a tree, or to a fence, and leave it out there for two nights and it will record the specific noises that the microbats make."

Another bat-detection device used by scientists and bat buffs is the echometer.

Just plug in the echometer to your tablet device to see and hear calls of native microbats. ( ABC Hobart: Carol Raabus )

This small detector plugs into a tablet device to convert their high-pitched echolocation sonar calls into an audible sound that humans can hear.

"We are picking up that microbats are living in people's backyards," Ms Saris said.

"So I think it gets people excited knowing that they're living there."

If you would like to capture the whereabouts and sounds of microbats, contact the Mallee Catchment Management Authority at reception@malleecma.com.au.