The terms ‘bamboo’, ‘rats’ , ‘flower’ and ‘famine’ do not really seem connected with each other. However, every half century or so, the connection between these four becomes obvious in India.
I heard of Bamboo flowering as a major event for the first time, when I talked to a wildlife guard in Nagarhole National Park. We talked about elephants, and how they sometimes can become a problem for farmers, raiding their fields for crops, when the guard mentioned that these incidents would increase over the next few years, as the bamboo flower had started.
Bamboo flower? Elephants? I was quite puzzled. He explained that one of the main food sources of elephants is the giant Bamboo, and that this species of bamboo flowers every 40-50 years all over India at the same time. After flowering and producing incredible amounts of seeds, all plants die. Hence the elephants starve and start looking for alternative food sources and become a nuisance for farmers.
The second time I heard of the bamboo flower was while travelling in Kerala, where I purchased some bamboo rice, supposedly at best a natural aphrodisiac, but healthy at the least. Quite costly though, and quite tasty. While negotiating the price I watched a group of monkeys plucking the seeds of the bamboo plants. They looked fat and healthy. Convinced me to purchase the bamboo rice.
Happy monkeys, hungry elephants, what else? Well there is an even more dramatic and tragic connection between rats and the bamboo flower. The amount of seeds produced by a single bamboo plant is immense and feeds a number of animals, among all others rodents seem to profit a lot from the bamboo flower. The Eastern regions of India, especially the state of Mizoram are, to a large extent, covered with giant bamboo (Melcocanna baccifera). On the one hand, this bamboo provides building materials, tools and even food (remember the bamboo shoots, you might have come across in a Chinese restaurant?) to the locals, on the other hand, once it starts flowering it initiates a dangerous chain reaction.
Once the bamboo bears fruit, millions of bandicoot rats (in this case mainly: Bandicota savilei) are attracted by the bounty of this easily accessible source of protein. They do what they are best at; eat and breed. Considering that these rats can produce a litter every three weeks and baby rats can reach maturity within 50 – 60 days, the numbers of rodents reach huge numbers within a short period.
The problem that arises from this fast multiplication is that even though bamboo seed resources are vast, they are limited. Once everything is finished, hungry rats come out of the bamboo forest and raid the farmers’ fields. Since there are millions of them, there is no remorse and everything is consumed, leaving the farmers and their families starving. Local administration tried to fight the army of rodents, offering the equivalent of USD 2.50 for every 100 rats killed. When the bamboo flowering started, villagers killed around 500,000 rodents a year; 2 years later in the peak of the bamboo flower they already killed 2.5 million rats per year.
However, even by killing 2.5 million of rats, it is still not possible to prevent multitude of rats from marauding the fields; they leave nothing for the farmers. In the past there have been major famines caused by the flood of rats subsequently to bamboo flowering. This time the local government has taken provisions to store more food in rodent-proof warehouses to prevent another famine. According to a BBC report pest control measures are largely un-coordinated and on an individual scale, hence not sufficient. Preparation and an integrated approach will be the solution to prevent the next army of marauding rodents, in a few decades.
Driving through National parks, and seeing the dead bamboo is a somewhat depressing sight. It will take a few years for new plants to grow to the imposing size of their parents. By the way, did you know that the aphids on the giant bamboo are very large and the food source for the largest ladybug in the world?