India loses track of its big cats
The study, by US and Indian scientists, criticises India's use of tiger footprints — which were thought to be unique — to track specific cats and calculate population size. The researchers say that in a recent controlled test, even experts were unable to distinguish the prints of individual tigers.
To better measure tiger trends, the scientists recommend that India adopts statistically sound sampling methods such as modern camera traps set in prime tiger habitat.
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Reference: Science 300, 1355 (2003)