COMMUNICATING WITH AFRICAN WILD DOGS USING BIOBOUNDARY CHEMICAL SIGNALS

African wild dog overmarking a synthetic (lab produced artificial) scent mark precisely as if it were a natural scent mark.

A few months ago, Botswana Predator Conservation’s BioBoundary project documented a critical milestone. We captured for the first time the evidence that African wild dogs respond behaviourally to single lab produced components of their territorial scent mark signals in the same way they do to natural scent-marks. 

When an African wild dog pack visits one of the scent-marking sites that they share with their neighbours, all the dogs in the pack sniff around – detecting and deciphering the scent messages left by previous visitors, then urinating or defecating over the previous visitors’ marks – a behaviour called “overmarking". These exchanges of scent messages allow the packs to communicate while avoiding trespassing into neighbours core home ranges and/or having to meet directly, which can lead to fatal interactions. 

The BioBoundary Project is working towards co-opting this territorial scent communication by using artificial scent-marks to deter wild dogs from crossing the borders of wildlife areas into human-dominated landscapes where they come into lethal conflict with humans over attacks on livestock. 

The wild dogs’ scent signals are carried by their urine and faeces, and the first step in recreating them has been to identify the volatile organic chemicals that carry the signals. As the BioBoundary project’s senior researcher, I have identified well over 100 of the components of the odours, but that complexity makes it technically impractical and financially unrealistic to create facsimile copies of natural scent-marks. Working versions of the artificial scent marks must be simplified versions of the natural ones, containing only the components that carry the all-important territorial “Keep Out” signal.  

PhD Student John Neelo sets the synthetic scent marks at a known marking site.

To investigate this, we are running tests at neighbouring wild dog packs’ scent-marking sites, where we know from 1000’s of camera trap videos that wild dogs respond to natural scent-marks by overmarking.  The components of scent marks that we will include in the formula of an artificial scent mark will depend on the results from these tests and the dogs’ responses to the single and simple mixtures of lab identified candidate components.  

The actual rate of release into the air of an artificial scent mark is estimated at micrograms (millionths of a gram) per hour as the scent diffuses through a thin membrane covering the vial of target compound. The controlled-release vials are protected from elephants, hyaenas, and from the wild dogs that we hope are particularly attracted to them, by metal housings made from galvanised plumbing connectors bolted to metal stakes hammered into the ground which enables release of the scent at ground level to replicate natural marks. 

A positive test result in this experimental set-up is one or more dogs sniffing and overmarking an artificial scent. AND we recorded this for the first time recently! The behaviours can be seen clearly in this camera trap video https://www.youtube.com/watch?v=EzNgoPa4Or0. The sniffing and overmarking behaviours of the artificial scent that you see are identical in every respect to how the dogs overmark natural scent marks. All compounds, like this one, that dogs respond to will be included in the synthetic (lab produced) scent marks that will be tested in pilot-scale BioBoundary deployments. 

This time of year is the denning season for Botswana’s wild dogs, so we do not run experiments during this period.  However, once the packs are mobile again, and visiting their territorial shared marking sites, we will conduct more tests at more sites and with different packs before expanding the field trials with additional candidate components of the dogs’ natural scents. 

As well as being a critical step towards cost-effective and ecologically benign protection of African wild dog populations, these overmarking responses add to our other BioBoundary breakthroughs with other predator species outside protected areas.  We are excited about these recent advances and emphasize that Botswana Predator Conservation’s BioBoundary project is the only research project successfully influencing wild predator behaviour using chemical signals.