discussion / Sensors  / 12 August 2021

Proximity detection in koalas


Hi Sensors People, 

I am new to WILDLABS and excited to be here!

I am researching the behavioural ecology of koalas in South Australia. I am trying to figure out if it is possible to use proximity detectors to monitor social interactions between koalas. The goal is to build a social interaction network among koalas in a given habitat area to understand social interactions between koalas relate to disease transmission and population genetic structure.

We already have GPS trackers which we are starting to deploy now for other aims, but the margin of error on the GPS locations is too large to be able to reliably say when two koalas are interacting. 

Does anyone know of an existing solution or have any suggestions for where we might start to look for information to develop our own proximity sensors?

Many thanks,


Hi Julian.

It sounds like you want proximity sensing, but also in an omni-directional way, rather than in a specific direction. If that's the case, I recommend using low power wireless radios.  LoRa might also work, but it's optimized for long range whereas you want to detect short range. If you have low power 2.4 GHz radios, you can send out periodic broadcasts and measure the signal strength of neighboring radios that you receive. The stronger the signal strength, the closer the proximity. It won't give an accurate distance, but since the signal strength drops off rapidly with distance, stronger signal strengths would imply much closer proximity than weaker signal strenghts. 

If you have questions about where to start, let me know since I work with wireless radios quite a bit. 


Hi Julian  

 I think Bluetooth 5.2 will help you to find out the social interactions between koalas. 

I am in Melbourne and work in the agriculture industry.

Best Regards,


Hi Akiba and James, 

Thank you both so much for replying to my query. Your suggested solutions are both very interesting and I know virtually nothing about both of them. So I will have a closer look into your suggestions, which will no doubt raise some questions for me and I'll get back in touch.

Thanks again!


Heya mate! 

What a delight to catch a note from you via wildlabs! We miss you over here in QLD! Are you in contact with QLD or NSW folks using a variety of detection and behaviour monitoring? Some are using various GPS techniques, while others are using acoustic sensing. Koala vocalisations, unlike the ole Eastern bristlebirds, are stacked and unique to anything else in the soundscape, so they are a good candidate in some soundscapes, depending on the detail of behaviour analysis, the potential of using an array, and other important considerations common consider for acoustic sensing more broadly. Bill Ellis, Sean Fitzgibbon, Ben Barth (folks I know from UQ in the past) and Brad Law (NSW DPI, if I remember correctly) are a few folks who come to mind who have used several technologies to generally detect or learn behaviours of koalas. Whether they have put out reports or academic journals about behaviour stuff specifically, I am not sure, but given my own explorations with using acoustic sensing know of these papers:

Bradley Law, Leroy Gonsalves, Rohan Bilney, Jess Peterie, Rod Pietsch, Paul Roe, & Anthony Truskinger. (2020). Using Passive Acoustic Recording and Automated Call Identification to Survey Koalas in the Southern Forests of New South Wales. Australian Zoologist, 40(3), 477-486. https://doi.org/10.7882/AZ.2019.033

Ellis, W. A., Fitzgibbon, S. I., Roe, P., Bercovitch, F. B., & Wilson, R. (2010). Unraveling the mystery of koala vocalisations: acoustic sensor network and GPS technology reveals males bellow to serenade females. Integrative and Comparative Biology, 50, E49-E49.