Echidnas are only one of two surviving monotremes in Australia (the other is the platypus) and the most widely distributed, yet very little is known about these spiky, ambling creatures.
Thanks to new research by Dr Christine Cooper from the Curtin Department of Environment and Agriculture in collaboration with Dr Christofer Clemente from the University of the Sunshine Coast and Professor Phil Withers from UWA, the habits of the short-beaked echidna have come to light, including the vital role they play in Australia’s ecosystems.
“The purpose of this study was to understand how echidnas move, because they have a really unusual anatomy,” says Cooper. “Part of their anatomy is more reptilian, and part of it is more mammalian, but they’re not really like either group.
We wanted to know how their anatomy influences their activity patterns and what sort of impact their activity has on the environment.”
Echidnas belong to a group of unique mammals called monotremes, which reproduce by laying eggs. Another unusual thing about echidnas are their limbs, which, although short, are extremely powerful. Echidnas use these powerful limbs to dig for ants or termites, their primary food source, or to burrow into the ground to escape from predators or high temperatures.
To understand just how active echidnas are and how much they dig, Cooper and the research team attached custom-made accelerometers and GPS units to echidnas located at Dryandra Woodland.
“An accelerometer essentially works like a Fitbit,” explains Cooper. “It detects movements in three different planes. They’re about the size of a wristwatch and these ones were hand-soldered with a microscope and tiny soldering iron. We then taped them to a cradle that was glued to the echidnas’ spines [these spines will later grow out and the cradle will fall off]. The accelerometers let us determine exactly when and for how long echidnas are resting, walking and digging.”
Dr Cooper and the research team knew that echidna digging has many positive benefits for the environment, but they were amazed at how much soil an individual echidna could turn over.
“They did a lot more digging than we anticipated,” says Cooper. “One echidna can potentially move up to 200 cubic metres of soil over 12 months – so if you have 12 echidnas, that’s an Olympic size swimming pool they can move.”
This really highlights the critical impact echidnas have on the ecosystem. As they dig, they turn the soil over, so they prevent the soil becoming compacted. Digging improves water penetration, prevents run off and erosion. It also incorporates a lot of seeds and leaves into the soil, which improves its organic content.”
Cooper describes echidnas as ‘ecosystem engineers’ because their digging ultimately encourages plant growth and species diversity. Australia once had many mammals that performed this role, such as bilbies and bandicoots, but feral predation, habitat clearance and fire regimes have drastically reduced or wiped out entire populations of these species.
“With a lot of other native mammals, once you have habitat modification, introduced predators are usually the last straw. As soon as cats and foxes come along, that’s it for them,” explains Cooper. “But because echidnas have their spines as a defence, they haven’t declined as much as other species.”
Dryandra Woodland, where the researchers studied the echidnas, is protected by the Department of Parks and Wildlife. The department manages feral predators in the area, giving echidnas the chance to flourish, meaning ample study participants for the researchers. But Cooper stresses that we need to better value our unique native animals and their habitats if we want them to have a future.
“Australia has the world’s worst conservation record. In the last 200 years we’ve lost more species than anywhere else,” she says. “There is a lot more that we can do and should do to help protect our biodiversity, but people need to really value their native fauna and flora, and understand it – knowing about it is a really important step.”
The research was funded by a UWA-UQ Bilateral Research Collaboration Award. The findings of the study have been published in the Journal of Experimental Biology and will potentially lead to further research opportunities to find out more about these cryptic creatures.