A recent study found that endangered lion-tailed macaques (LTM) in the Valparai plateau are forming unusually large groups in private plantations outside protected forest areas. At Puthuthottam, one group had 117 monkeys, much larger than the typical group size of under 20 in protected forests of the Western Ghats. Another LTM group at Puthuthottam numbered 51, while Korangumudi had 78 individuals in one group. These areas, including Puthuthottam, Pannimedu, Korangumudi, and Tata Coffee, are private plantations surveyed alongside protected forest fragments. The total LTM population on the Valparai plateau, part of the Anamalai Tiger Reserve, is about 800 monkeys in 37 groups. Most groups (29) live in protected fragments, with eight groups in private plantations. Long-term data show a rise in group sizes in private plantations: a Puthuthottam group grew from 17 monkeys in 1984 to 225 monkeys across five groups in 2024. Korangumudi’s group grew from 19 monkeys in 1990 to 83 in 2021. Tata Coffee and Pannimedu groups also increased recently. Dr. Honnavalli N. Kumara from the Salim Ali Centre for Ornithology and Natural History said, "The population of LTMs in all protected areas was relatively stable while steady growth was observed in private fragments like Puthuthottam and Korangumudi." He warned that monkeys visiting human areas and being fed by people could change their behavior and impact population dynamics. The study suggests that easy access to human food, cultivated fruits, and the monkeys’ adaptation to humans may explain the rapid growth at Puthuthottam. The research, co-authored by Santanu Mahato and others, was published on February 18, 2026.