New Delhi: After the government announced in July that the country’s tiger population had grown from 1,411 in 2006 to 2,967 in 2019, an investigation by the Indian Express has uncovered potential distortions in the counting process. It concludes that, among other things, as many as one in seven tigers could have been photographed twice.
While releasing the All India Tiger Estimation Report 2018, Prime Minister Narendra Modi had said that the country had emerged as one of the biggest and safest habitats for tigers in the world. While the tiger population nationwide has gone up, the Indian Express effort has raised some questions about the counting process behind the scenes.
According to government data, of the 2,967 tigers across the country, 2,462 – or nearly 83% – of them had been photographed during the surveying phase. This indicated a rise from the previous survey in 2015, which counted 2,226 tigers with photographs for 73% of them.
According to the newspaper’s report, government officials maintained that while the photos from the latest survey hadn’t been made public yet, pictures from the previous one in 2015 indicated the country had a large population by virtue of there being so many photographs. In other words, photographic evidence was thought to be hard to fake – and the investigation has turned the spotlight on this idea.
According to the Indian Express report, multiple photos attached to the 2015 survey exhibited glaring discrepancies. The report added that 221 photos should not have been counted according to the norms established for wildlife population estimation. The population survey, undertaken by the Wildlife Institute of India and the National Tiger Conservation Authority, could then have overestimated the number of tigers by 16%.
Additionally, the survey also seems to have (inadvertently or otherwise) included 51 duplicates and 46 cubs below the cut-off age of 12-18 months[footnote]Such young tigers aren’t usually included because they are often killed by predators.[/footnote].
Also read: How the Tiger Census Estimated India Now Has 2,967 Tigers
Next, to keep from photographing the same tiger twice, researchers set up two camera traps facing each other on either side of a path that a tiger is likely to cross. When the tiger does cross, the traps are triggered and the cameras take pictures: one of the tiger’s right flank and the other of the tiger’s right. Since a tiger can be identified by unique stripes on its right and left side, the Indian Express argues that photos capturing only one flank should be discarded if they depict skin patterns that can be found in other double-flank photos. Such photos number 136.
Finally, the investigation found at least 49 photos to be unreliable because the picture only contained a tiger’s animal’s tail or whiskers, considered insufficient for matching tiger stripes. For instance, a picture with only the head of a tiger couldn’t be used to confirm its identity because it was not a reliably unique identifier.
All together, the newspaper contested 282 photos, bring the total number of photographed tigers down from 1,696 to 1,414. More than calling attention to the numbers of a single survey, the Indian Express‘s report casts doubts on whether future surveys can build on the data it produced and, more problematically, on the counting process itself.