Better understanding Death Adders
Death Adders are a highly venomous, iconic snake which occurs throughout Australia, yet remarkably little is known about their ecology, particularly movement patterns and response to translocations. Some populations have experienced catastrophic decreases in population upon the arrival of the poisonous, feral Cane Toad, while others surprisingly increased. Being an ‘ambush’ predator which is highly cryptic, their reluctance to move or be seen when intimidated renders them a potential serious hazard to bush walkers, land workers, and pets. Knowing more about their movement patterns (e.g. peak movement periods, overwintering sites) will thus help reduce the human– and pet-snake conflict in Australia, especially in regions where Death Adders are particularly prevalent. Furthermore, Death Adders, like many other species of snakes across Australia, are being translocated from private residences without any knowledge of the consequences (e.g. home range increases, snake death) of this management action. In four weeks, we located 10 Death Adders, five of which were large enough to attach external radio-trackers to. We were able to monitor their movements in an urban-bush interface for up to four weeks.
From this immense effort, we have published one paper (see below) from this work to date (May 2023). We're also working on another paper that will hopefully inform management strategies regarding this species, particularly regarding the popular management strategy of snake relocation.
We hope that our years of effort on this project can ameliorate the human-snake conflict in Australia, plus aid in conservation efforts of decimated populations.
In further efforts to help reduce the human-snake conflict, I have joined forces with Save the Snakes as a member of the group's Advisory Committee, providing input and advice to the organisation.
Death Adders on
Emmy Award-winning TV!
Phil Breslin, Presenter and Producer of the ABC wildlife series, Built to Survive, was fascinated by Death Adders and asked me to help him find one for an episode. So, Chris Hay and I delivered! Some pics below of the experience.
Our Latest Death Adder Publication!
Abstract: Snakes are a particularly neglected taxon within the field of wildlife management and conservation. Although research provides knowledge for evidence-based decision making, many factors hinder snake research. Challenging logistics regarding tracker attachment is one such factor. Radiotelemetry is a widely used method to track snakes, but internal implants require prohibitively expensive surgeries (two per snake), can result in potentially fatal infections, and are unsuitable for small snakes. Several methods for temporarily attaching external trackers to snakes have largely failed. The subdermal stitch method for external transmitter attachment, however, appears to be a viable alternative, with fewer complications and injuries than the glue and glue-and-tape methods. We tested the efficacy of using the subdermal stitch method to attach radio-transmitters externally to Common Death Adders (Acanthophis antarcticus). In this pilot study, we tracked five individuals for 5–33 d (mean 20.8 d; median 21 d) on Magnetic Island, Queensland, Australia, in November and December 2018. We encountered multiple issues associated with the external attachment technique in death adders, including wounds to the tail (although none required veterinary services) and several entanglement hazards, one of which resulted in the death of one individual. We compare our experiences to previous studies, provide nine key recommendations that will guide future pilot studies to successfully test this technique, and call for more pilot studies to test this technique on snake species that range in ecology, morphology, and behavior.
Venom studies
Myself and colleagues managed to develop an entirely new assay which enables us to study neurotoxicity of snake venoms across specific prey-type targets, without using animal models! This animal-free, cell-free technique uses synthetic peptides linked to a biosensor to measure biomolecular interactions with extreme accuracy. Using this versatile technique, we published a paper (Zdenek et al., 2019) in the international journal, Toxins, showing that the neurotoxins in Death Adder venom broadly target many prey types. That is, their venom does not target one specific prey type (e.g. amphibians). Being an ambush predator, they probably cannot afford to be picky in their diet!
Translocation Studies
After 2 years of permit acquisition, animal ethics applications, and grant applications, we could finally head to the field on Magnetic Island (QLD, Australia), to find and track Death Adders. In five weeks of hiking 10 hours a day in temperatures up to 38ºC, we managed to located 10 Death Adders, five of which were large enough to attach external radio-trackers to. We were able to monitor their movements every day, measuring the distance travelled overnight, as well as many micro-habitat and climatic data associated with each individual. We are currently in the analysis phase, with the aim of publishing our work in The Journal of Herpetology.
The Problem
Magnetic Island is well-known for death adders which are regularly encountered by humans and thus provides a unique opportunity to investigate the ecology and relocation-response of this cryptic species. The human-snake conflict on this island is particularly acute, with several people a year being air-lifted off the island from Death Adder bites. Further worrisome is the unfortunate pet-snake conflict experienced on Magnetic Island; on one occasion, for example, up to four dogs in two weeks died due to Death Adder bite. One particular bad year left 10 dogs and two cats dead from Death Adder bites. With a population of only 2,200 people on the island, this unsettling high rate of Death Adder envenomation illustrates a clear conflict, which could quite possibly be occurring in other Death-Adder prevalent regions, that requires research to inform management and behaviour decisions to best reduce human– and pet-snake conflicts.
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The Solution
This work will provide the framework for understanding Death Adder ecology, and this understanding is crucial for the management and conservation of the species. National Parks rangers and biological consultants throughout Australia will be better equipped with the required knowledge to not only survey for this Vulnerable species but make important land-management decisions that enable the persistence of this top-predator in the landscape. In addition, this project will provide critical recommendations to optimise the popular management strategy of relocating unwanted Death Adders from human dwellings. Furthermore, after publications and solid conclusions emerge from this project, National Parks rangers on Magnetic Island will have the capacity to better answer important questions from tourists and residents about co-existing with Death Adders.
Another Scientific Paper Publication
Death Adder venom
Myself and colleagues at The Venom Evolution Lab at The University of Queensland developed an innovative method to measure neurotoxicity produced by snake venoms upon their natural prey targets. We managed to do this without using cell lines or animal models, meaning that our method is extremely high-throughput, flexible, and versatile.
Our new method, based on an established technology called bio-layer interferometry, allowed us to test Death Adder venom, among other snake venoms, upon neurological targets from various prey items such as rat, amphibian, marsupial, bird, and lizard. We found that Death Adder venom from the species Acanthophis antarcticus targeted a wide variety of prey items, not singling out any one particular prey type, unlike the King Cobra (Ophiophagus hannah) which strongly targets snake neurons disproportionately (they prey mainly upon other snakes).
This research sheds light upon the ecology of the death adder, indicating that, because they're an ambush predator, perhaps they cannot afford to have a picky diet!
Here is a video showing and describing the method. Here is the full paper, open access ; ).
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