NOVA teams up with National Geographic to explore why mysterious rat
plagues ravage northeast India every 48 years.
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travels to the northeastern Indian state of Mizoram, where rats
are estimated to have eaten more than 50,000 metric tons of
rice, devastating the farmers' fields.
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visits the remote village of Thlangkang, where rats have
devoured farmers' rice and corn crops.
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reports that the majority of rats causing the damage are black
rats, likely because their rapid breeding and early weaning give
them an advantage over their competitors.
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reveals that the rat population explodes every 48 years,
coinciding with the blossoming and fruiting of the local bamboo
plant, an ecological event known by the local people as
mautam.
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follows biologists to the Mizoram village of Zamuang, where the
mautam has occurred but the rats have not yet invaded the
fields.
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notes that although black rats are normally kept in check
because the forest offers little to eat, over the course of the
bamboo fruiting each of the well-fed females can start a cycle
that results in up to 200 offspring.
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states that bamboo is a grass that is inexpensive, versatile in
its use, and ten times stronger than steel.
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describes how bamboo spreads by underground rhizomes.
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explains that the large fruiting event ensures the plant's
survival—so much seed is produced that predators cannot
eat it all, thus allowing the plant to germinate and produce new
bamboo.
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introduces four methods biologists use to determine how many
rats are in one farmer's rice field and the forest that
surrounds it.
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tracks how the rat population in Zamuang grows in distinct
pulses.
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reports how the Zamuang rice fields avoid extensive damage
despite a substantial increase in the rat population.
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returns to Thlangkang, where scientists determine why the fields
were devastated there and not in Zamuang.
