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By Sally-Ann Jones

How do echidnas handle the cold?

Researchers are about to strap lightweight sensors onto wild echidnas to better understand how they deal with temperature extremes.

Winthrop Professor Phil Withers in the School of Animal Biology is an expert in the different ways animals cope with desert conditions and has studied many Australian native animals, including burrowing spiders, ash-grey mice, numbats, dunnarts, birds, and various reptiles such as yellow-spotted monitor lizards.

But this is the first time he has taken a long hard look at echidnas - which feature on our five-cent coin - and he is particularly excited about this project, a collaboration between UWA and the University of Queensland.

Thanks to high-tech sensors, Professor Withers and his team will be able to log the day and night movements of a population of echidnas in the Dryandra region 160km south-east of Perth. The sensors monitor movements with an accelerometer, ambient light and temperature, and GPS position.

The sensors are being developed by engineers at UQ with input from one of Professor Withers' former PhD students, Dr Chris Clemente, a biologist with a passion for technology, now at UQ. These sensors will enable researchers to answer important evolutionary questions and better understand how the animals use the various micro-habitats in their environment. The echidna field work aspect of the study will be undertaken with another of Professor Withers' former PhD students, Dr Christine Cooper, a comparative physiologist now at Curtin University.

"Echidnas are one of Australia's most distinguishable and iconic species," Professor Withers said. "Yet we know relatively little about them on mainland Australia, because they're secretive."

The platypus, which is semi-aquatic, and the echidna are the world's only living monotreme mammals. This means they lay eggs. They are mostly solitary, although they suckle their young, once they've hatched, for months. But unlike egg-laying reptiles, the platypus and the echidna are endothermic with a high metabolic rate." Echidnas' body temperatures can vary from between less than 20 to about 34°C - humans, in comparison, have a constant body temperature of about 37°C.

"Using our sensor systems, we'll develop a detailed picture of their thermal ecology and movements," Professor Withers said.

Professor Withers said that echidnas eat thousands of ants or termites each day. It is well known that echidnas hibernate, for up to three months, in Tasmania's snowy mountains - but it isn't clear what they do in Western Australia where it is not so cold in winter.

During the hot summer in WA, they forage for ants and termites in the coolest times of the day. At the moment, it is thought that echidnas don't sweat and they don't pant - but somehow can manage to keep their body temperature below environmental temperatures.

"We're interested in the extent to which echidnas regulate their internal body temperature by a combination of physiology and behaviour, compared to how reptiles rely on external heat to thermoregulate. This will enable us to understand how early mammals have made the transition from being ectotherms to endotherms," Professor Withers said.

While the new sensors will enable these biologists to predict the effects of agriculture, land degradation and a changing climate on echidnas, Professor Withers and his team hope to develop sensors suitable for a wide range of animals and to implement analysis software to quickly and easily interpret the large amounts of data collected by these sophisticated data logging systems.