Tigers More Stressed Affecting Reproduction, Finds Study
HYDERABAD-Tourism and human activity are increasing stress levels among tigers and affecting their breeding patterns in India’s tiger reserves, according to a new study conducted by the CSIR-Centre for Cellular and Molecular Biology (CCMB).
The study, published in the Zoological Society of London journal Animal Conservation, is the first to combine non-invasive stress and reproductive hormone analyses from tigers across five major Indian tiger reserves – Corbett in Uttarakhand, Tadoba-Andhari in Maharashtra, Kanha and Bandhavgarh in Madhya Pradesh, and Periyar in Kerala.
Earlier studies led by Dr G. Umapathy, Chief Scientist at CSIR-CCMB, had established that tourism and other human activities in tiger reserves cause stress in tigers. In the latest study, his team systematically examined how such disturbances affect tiger breeding.
For the first time, scientists tracked tigers across different regions of India through four seasons over a two-year period to understand how human presence impacts tiger well-being.
The team analyzed 610 genetically confirmed tiger scat samples, including 291 from females and 185 from males, collected between 2020 and 2023. Researchers measured faecal glucocorticoid metabolites, a biomarker of stress, and faecal progesterone metabolites, an indicator of breeding activity in female tigers.
The study found that tigers living near tourism roads and areas with greater human disturbance consistently showed elevated stress hormone levels across all reserves.
Researchers also found that tigers in strictly protected core zones showed higher stress responses to human disturbance than those in multi-use buffer zones.
According to the study, buffer-zone tigers appear to have adapted to year-round human presence, while tigers in core zones experience sharp spikes in stress when seasonal tourism enters these areas. The effect was found to be most pronounced in Tadoba and Bandhavgarh tiger reserves.
“Tigresses prefer to breed in the quiet parts of the forests. However, it is becoming difficult to find such suitable areas. In Tadoba and Corbett, the buffer zones already have high tiger populations. It is concerning if the core areas of the forests also become stressful for the tigresses,” the report said.
“Not only is the reproductive success of tigers lower under stress, but the young ones will also grow up differently in such conditions,” it added.
The study recommended strict regulation of tourist vehicle numbers and prevention of vehicle crowding at tiger sightings. It also suggested reducing safari duration by around one hour during both morning and evening sessions.
Other recommendations included stronger management of buffer zones, particularly in Tadoba and Bandhavgarh, creation of additional water bodies along non-tourism routes to reduce dependence on roadside waterholes, and continuous non-invasive monitoring of tigresses to identify and protect breeding hotspots. (IANS)
