As the sun slips behind the Lushai Hills, groups of farmers in Maulcheng village in Lunglei, Mizoram, set out for their jhum fields carrying bundles of bamboo traps. They meticulously set them before darkness falls, returning a few hours later to find most of them holding a rat.

After nearly five decades, the dreaded “Thingtam” returned to Mizoram late last year. Thingtam is a period marked by an exploding rodent population that raids fields and granaries night after night. A farmer may lay over 30 traps in one hectare in a single evening. Within hours, most will spring shut, and the cycle is repeated twice, sometimes thrice, before dawn.

C. Lalhriliana, one of the farmers, says that agriculture is the mainstay for 60 households in the village, which cultivate rice and ginger across about 1.5 sq. km. “The destruction wasn’t limited to surface crops; even root vegetables like yams and ginger were eaten. I lost almost ₹25,000. Now I must buy rice from the market to feed my family of seven, which will severely strain my household budget,” he adds.

Almost every village across the state had the same nightly ritual which continues even today though the infestation has reduced in parts.

Lalrautkima, vice president of the Mamte Village Council, informs Mongabay-India that nearly 90% of the 130 households farm 20,000 to 30,000 square metre of jhum each. This Mongabay-India reporter met the villagers for an interview late last year. “Every year, villagers set traps for bamboo rats around November and December. The meat is considered a delicacy,” he says. “However, the severity of this year’s (2025) outbreak forced us to begin trapping as early as June.”

Some are consumed, while the surplus is fire-dried and sold in local markets, fetching approximately ₹200 for six to eight pieces.

Bamboo death as cause

Mizoram boasts expansive bamboo forests that cover nearly 57% of its total geographical area of 21,087 sq km. The state is home to more than 20 bamboo species across nine genera. Of these, Melocanna baccifera, locally known as Mautuk or Muli, accounts for nearly 90% of the bamboo growing stock. Among the remaining species, about half are Bambusa tulda, called Rawthing. Both species flower, bear fruit, and die after a lifespan of 48 to 50 years. The fruit, rich in nutrients, triggers a population boom among rodents, with some accounts suggesting that rats even migrate from neighbouring areas to gorge on the sudden abundance.

As the bamboo fruit supply is exhausted, the burgeoning rat population spills out of the forests and into human settlements. Fields are soon overrun, triggering widespread crop destruction.

The flowering of Mautuk and the destruction that follows is known as Mautam — from mau, meaning bamboo, and tam, meaning death. A similar cycle linked to the flowering of Rawthing is called Thingtam, also known as Rawtam.

Flowering begins with a preliminary phase, known locally as Sehsam, when only a few plants of the species start to bloom, followed by Sehkum, the year when bamboo flowers en masse.

Famine to statehood

In 1881, the British encountered an explosion of rats following the gregarious flowering of bamboo in the Lushai Hills (now the Mizo Hills), a part of the Indo-Burmese hill range. The rodents devoured standing crops and plunged the hills into famine, killing an estimated 15,000 people. The same cycle returned in 1912, spreading hunger across the Mizo, Chin and Chittagong Hills, including areas under Burmese rule.

Colonial records, cited by Sajal Nag, a professor, in his study, describe farmers setting hundreds of traps, with some individuals catching up to 500 rats in a single night. The rats were dried for food but could not replace rice, the staple diet. For many, survival meant foraging for roots and wild yams as granaries were overrun. In December 1924, an estimated 45,000 to 50,000 rats were killed in the then Aizawl subdivision alone.

For generations, Mizos have learned to read the signs of these events in their surroundings, drawing on memory and lived experience to anticipate the next famine. Typically, there is an 18-year gap between a Mautam and a Thingtam, and a 30-year interval between a Thingtam and the next Mautam. As per established patterns, the 2025 Thingtam was accurately predicted.

Bamboo flowering and rodent infestation cycles in Mizoram

In 1958, the Mizo District Council warned the then Assam government of an impending Mautam-induced famine and sought financial assistance as a preventive measure. The request was rejected, and the prediction was dismissed as “superstition”. When famine struck, the administration was unprepared. In response, a welfare organisation, the Mizo National Famine Front, emerged in 1960, mobilising relief and rehabilitation for famine-stricken communities.

“In 1961, the group dropped the word ‘famine’ from its name to become the Mizo National Front (MNF). Continued delays and apathy from the Assam and the Central governments, among other issues, deepened public disillusionment. The Front transformed into an ethnic political force demanding a sovereign Mizoram — a movement that culminated in a 20-year insurgency, ending with the Peace Accord of 1987,” says Pu Zoramthanga, who was second-in-command in the guerrilla movement and later served three terms as the chief minister of Mizoram.

The return of Thingtam

Deputy Director (Plant Protection) Lalrindiki shares, “Sporadic flowering of B. tulda was initially spotted in February 2024 at Hriphaw in Mamit district. Later that year, flowering was observed in 15 more villages across Mamit, Aizawl and Lunglei districts.”

Official records show that by the end of the 2025 harvest season, 5,317 farmers across all 11 districts had been affected by rodent infestation. Nearly 42% of crops were damaged, impacting about 4,307 tin (approximately 4,000 sq. metres) of land. At least 32,375 rodents were collected and either burned or buried in 2025, excluding the several hundred that were consumed.

District-wise crop losses during the 2025 thingtam:

“One of the precursors of the rat infestation is the swarming of an insect locally known as ‘thangnang’ (Udonga montana, syn. Ochrophora montana). It is not known to damage agricultural crops, but its occurrence is rare and therefore warrants documentation. In 2024, swarming of thangnang was observed in a few villages. By 2025, 46 villages continued to report such swarms, except in Champhai and Khawzawl districts,” Lalrindiki points out.

“I have been cultivating rice on jhum fields for nearly 50 years. It is how I feed my family and educate my children,” says Maunsanga, a farmer from Mamte. “Earlier, sowing 16 kg of seed yielded 35 to 40 jute bags of rice, 45 kg each. This year, I harvested only three. Rats devour the crop at night and birds take the rest during the day. Without government support or compensation, we don’t know what we will eat.”

Moreover, bamboo takes years to regenerate, leaving large stretches of exposed soil. This is a serious concern in mountainous landscapes and a major setback for bamboo-dependent livelihoods. It also disrupts food availability for wildlife. This imbalance extends to public health, as surging rodent populations increase the risk of rodent-borne diseases, transmitted through bites, fleas and other ectoparasites, or through the contamination of food, water and air by rodent urine and excreta.

Laltlanhlua Zathang, Conservator of Forests, informs that while most parts of Mizoram witnessed gregarious flowering of B. tulda, some areas did not flower during this peak event year. “A follow-up flowering is expected in the remaining clumps. The Forest Department is monitoring the situation closely, though no fresh reports of flowering have been received so far,” he says.

Across bamboo species, three broad flowering patterns are recognised: annual, sporadic and gregarious. Annual flowering occurs in isolated individuals, while sporadic flowering appears irregularly in scattered clumps without a fixed cycle. Gregarious flowering, however, follows a long biological rhythm — about 48 years in B. tulda. Although the cycle length is broadly fixed, the mass flowering event itself may unfold over several years rather than a single season.

“Sporadic flowering in bamboos, including B. tulda, can be influenced by climatic and environmental factors,” explains Sandeep Yadav, Scientist D at the Forest Research Centre for Bamboo & Rattan (FRC-BR), Mizoram. “Local site conditions such as soil characteristics and underlying rock type may also shape flowering behaviour.” He adds that the current flowering cycle is not confined to Mizoram. “B. tulda has been flowering across the Northeast, including Tripura, wherever the species is distributed. The process appears to be occurring in phases, possibly reflecting differences among bamboo populations. In Mizoram, we expect the remaining clumps to flower this year, but there is no certainty.”

Despite decades of observation, the phenomenon remains poorly understood. According to Rajib Kumar Kalita, Scientist F at the Rain Forest Research Institute in Jorhat, bamboo flowering continues to puzzle botanists. “How individuals of a species remain vegetative for decades and then flower synchronously across large regions, regardless of the age of individual clumps, has not yet been conclusively explained.”

Bait shyness complicates rodent control

Around 12 rodent species have been recorded in Mizoram, but only six are commonly observed in bamboo flowering areas. Among them, the common house rat (Rattus rattus) is the predominant species responsible for crop damage.

About 186.67 kg of rodenticide (zinc phosphide) was distributed across Mizoram for mass poisoning drives. District Agriculture Officer of Lunglei (recently transferred elsewhere), Hmangaihchhunga says that the poison is typically mixed with rice and oil and placed in small bundles across the fields. “Due to bait or poison shyness among rats, the mixture has to be changed frequently. We are now adding dry fish to mask the smell of the poison.”

Farmers still prefer to use indigenous traps alongside poison. The Mizos make different kinds of traps with bamboo and metal wire — vaithang, chepthang and mangkhawng — each designed to trap different kinds of animals, including rats, civet cats and junglefowl, depending on their size. These are placed along rat movement routes after sunset.

At least 18 affected villages refused to use rodenticides, fearing that chemical poisoning could contaminate crops, soil and water. Local livelihoods are closely tied to water bodies, with villagers relying on fishing and crab collection as regular sources of income.

“Since reports of mass poisoning emerged, buyers have stopped purchasing fish and crabs in most village markets. The district administration has also imposed a ban on fishing,” Lalrautkima adds. Already reeling from heavy crop losses, the added blow to alternative income sources has left many households struggling to survive without compensation.

From crisis response to prevention

“Anticipating the 2007–08 Mautam, we initiated advance preparedness through the ambitious Bamboo Flowering and Famine Control Scheme (BAFFACOS) from 2004 to 2009, shifting the state’s response from crisis management to prevention,” said Pu Zoramthanga, the then chief minister. Mizoram sought ₹564.55 crores for its implementation, but only ₹125 crores was sanctioned by the Centre.

Implemented years ahead of the bamboo flowering, the programme coordinated 15 departments including agriculture, rural development, health, food and civil supplies, and forests to strengthen food security, diversify livelihoods and mitigate famine risks. Preparatory measures included village-level awareness campaigns on rodent control.

Further, the state promoted community-led rat control, offering ₹2 as an incentive per rat tail as proof of kill. A total of 15.10 lakh tails were submitted from all 11 districts, amounting to a payment of around ₹30 lakhs.

The 2007–08 Mautam was the first without deaths, but it affected 130,621 households across 769 villages. Paddy was the worst hit, with losses of 89.76%, while other crops recorded losses of around 60%. Overall losses were more than ₹400 crores. Director of Agriculture R. Lalnunzira said that while the 2025 Thingtam was not granted recognition as a state-specific disaster by the State Disaster Management Authority despite efforts by the agriculture department, the department plans to seek seed support for farmers and explore distribution under various schemes after assessing the financial losses at around ₹3 crores.

Banner image: A farmer tends to his field in Mamte village, Mizoram. Image by Surajit Sharma/Mongabay.

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Arathimenon Editor

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AgricultureHimalayasIndigenous PeoplesTribesVillagesMizoram

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