When a big cat like a tiger attacks a farmer's cow or goat, it's a serious problem, not just for the farmer who has lost a valuable animal but also for conservation efforts. Figuring out which predator is responsible has always been tricky, often relying on clues like paw prints or claw marks. However, these signs can be misleading; sometimes, the wrong animal is blamed, which doesn't solve the conflict and can even harm the local predator population.
In a new study, researchers from the National Centre for Biological Sciences (NCBS), Bengaluru, Panthera, USA, Sastra University, Thanjavur, Nature Conservation Foundation, and officials of the Madhya Pradesh Forest Department have shown that tiny traces of DNA from saliva, shed hair, or even scat (animal droppings) collected where livestock have been killed can successfully identify the individual predator involved.
"In communities that live in proximity to large carnivores, livestock depredation might cause conservation challenges. Systematic understanding of individuals involved in conflict is a critical first step towards a solution,” explained Prof. Uma Ramakrishnan, a professor at NCBS and the study's author.
The research team, working with Panthera, a charitable organisation devoted to preserving wild cats, and the Madhya Pradesh Forest Department, investigated 198 sites where livestock had been killed. The study area covered two important tiger habitats in Central India: Kanha and Bandhavgarh Tiger Reserves. At each location, they collected any potential non-invasive DNA samples or samples that could be collected without interacting with the animal.
Back in the lab, they used genetic tools based on Single-Nucleotide Polymorphisms (SNPs) and next-generation sequencing methods to identify individual tigers. An SNP (pronounced "snip") is exactly that: a variation at a single point (a single nucleotide or letter) in the DNA sequence. While one SNP might tell you if a tiger has an 'A' or a 'G' at a particular spot, it's not enough to tell individuals apart. However, looking at different SNP locations across the tiger's DNA produces a unique pattern. For their study, the team used up to 123 SNP markers from each sample, allowing them to identify the individual predator.
They found that shed hair samples worked best for identifying individual tigers, with saliva and scat also proving very useful. Impressively, they identified the species of predator (like confirming it was a tiger) in over 95% of cases using any of these samples, and they successfully identified individual tigers at 85% of all the kill sites.
However, just finding an animal's DNA at a kill site doesn't automatically mean it made the kill. Another animal might have come along to scavenge the remains. To address this, the team developed a clever classification system based on where the DNA was found, for example, saliva on a bite wound versus scat found further away, and the sample type. They assigned a confidence level to their identification: "true predator", meaning they were highly confident this animal made the kill; "circumstantial predator", with medium confidence; or "predator uncertain", with low confidence. Out of the 198 cases, 72 were classified with high confidence.
Himanshu Chhattani, the study's lead author, highlighted the importance of this, saying, “Genetic samples are often the only true evidence of a predation event and are therefore vital. While identification is possible, there remains some possibility of misidentification, especially when multiple individuals are present at the kill site. That’s why it’s important to assign confidence levels in identification."
This DNA-based approach gives wildlife managers a reliable, evidence-based tool to understand which specific animals are repeatedly involved in conflicts with livestock. This means that any actions, like potentially relocating an animal, can be targeted accurately, avoiding removing innocent individuals.
As Sanjay Shukla, former Principal Chief Conservator of Forests in Madhya Pradesh, put it, “As we celebrate the success of tiger recovery, the growing challenge of human-tiger conflict demands urgent attention. To address this effectively, interventions must be grounded in scientific evidence and rigorous methodologies. The genetic approaches outlined in this paper offer a reliable means of identifying individuals involved in conflicts, paving the way for more informed and strategic resolutions.”
This research article was written based on a Press Release by NCBS.