The hundreds of millions of animals killed on roads annually represent a “largely overlooked resource” that could revolutionise wildlife research and significantly reduce the need for live capture, according to a global review published in Biology Letters.
Led by RMIT University in collaboration with Western Sydney University, Deakin University, and Trent University, the study analysed 300 peer-reviewed papers from 67 countries. The researchers found that roadkill is already being used for a surprisingly wide range of scientific purposes, from mapping species distributions to monitoring environmental pollution.
Lead author Dr Christa Beckmann of RMIT’s School of Science argues that formalising this practice could transform the way data is collected, turning a ubiquitous ecological tragedy into a valuable scientific asset.
From disease tracking to rediscovery
The review highlights the versatility of carcasses as a data source. Beyond simple population counts, specimens collected from roadsides are being used to track the spread of invasive species, analyse animal diets, and supply essential material for museum collections.
On occasion, roadkill has even rewritten local natural histories.
“In some cases, roadkill has helped locate populations thought to be extinct or provided teaching material for university classrooms,” says Beckmann. “We found examples of successfully using roadkill to map species distributions, monitor disease and environmental pollution, study diets, track invasive species, supply museum collections, and even discover species previously unknown to science.”
An ethical alternative
One of the study’s most significant arguments is ethical. Traditional wildlife research often involves trapping, tagging, or handling live animals — invasive methods that can cause stress or harm. By utilising animals that have already died, scientists can adhere more closely to global ethical principles known as the “3Rs” (Replacement, Reduction, Refinement).
“Because the animals are already dead, researchers can often avoid live capture and handling, aligning perfectly with global animal-ethics principles that encourage replacing invasive methods wherever possible,” says Beckmann.
Safety and limitations
However, the transition to using roadkill is not without risks. The authors caution that handling carcasses requires strict protocols to manage the potential spread of disease and ensure researcher safety. They also note that this method is not a universal substitute for all field work.
“Obviously roadkill is not appropriate for all research and, if used, needs to be handled with appropriate health and safety precautions,” says Beckmann.
The study challenges the scientific community to reconsider how it sources biological data. Beckmann suggests that allowing these resources to decompose by the roadside is a missed opportunity for conservation science.
“While roadkill will always be tragic, using these losses wisely could help drive scientific discovery and conservation forward, rather than letting valuable information decompose by the roadside,” she concludes.
