The genetics of ghosts
Scientists are mapping the family trees of tigers they have never seen. In the Western Ghats of India, a sprawling biodiversity hotspot, researchers walk the same paths as tigers, collecting a unique source of data: their scat. These fecal samples are a genetic goldmine, allowing teams from institutions like the National Centre for Biological Sciences (NCBS) to extract the DNA of individual animals. This non-invasive technique helps scientists understand the lives of the elusive Bengal tiger, Panthera tigris tigris.
The studies focus on the vast Nilgiri Biosphere Reserve, a landscape that connects several protected areas, including Nagarhole National Park, Bandipur Tiger Reserve, and Mudumalai Tiger Reserve. By analyzing repeating segments of the genome called microsatellites, scientists can create a unique genetic fingerprint for each tiger. One study collected genetic data from 115 individual tigers across a 30,000 square kilometer area. This allows them to identify individuals, determine their sex, and, most importantly, uncover how they are related. The data reveals which tigers are mating, how far their offspring disperse, and how different populations are connected.