Chittagong Hill Tracts: Bamboo, Rats and Famine
Since 2007, unusually large numbers of rats have been flooding out of the forests of the Chittagong Hill Tracts (CHT), causing major suffering and hardship for local communities. These rat floods in the CHT are a real and scientifically accepted phenomenon, and similar events are known to periodically occur in many parts of the world.
Because there are suddenly so many rats, communities don't know how to control the problem, and the rats are devouring everything they can find in farmers' fields and houses. Many communities are left with nothing to eat. The destruction of people's livelihoods can be severe as the rats not only destroy all agricultural produce, but also ruin local stocks of yarn for weaving, finished goods such as blankets and clothing, and cause disease outbreaks by contaminating water supplies and/or biting people while they sleep. This crisis is more than just a regional problem confined to the people of the CHT, but has wide-sweeping implications for the entire country of Bangladesh with potentially major economic and political consequences for the nation.
Rat floods in the CHT are related to a little-known aspect on the biology of bamboo. Most types of bamboo undergo what is called "periodic gregarious mass flowering and seed masting". Unlike
many plants we know, bamboo does not produce flowers every year.
The type of bamboo commonly found in the CHT only flowers every 40-50 years. When this happens, all the bamboo across the CHT flowers and produces seed over a 3-4 year period. This bamboo flowering starts to the North of the CHT in the Indian states of Tripura and Mizoram, moving towards Bangladesh and onwards into Myanmar. Rats find the abundant bamboo seeds to be tasty and nutritious. With such an abundant food supply, the rats grow large and are able to produce many more young rats than they normally would. In this way, the rat population grows very large, and when the bamboo seeds are all gone, this very large population of rats moves out of the forest in search of other things to eat.
In this past year , the World Food Programme has been delivering emergency aid to some of the affected communities, but more needs to be done to deal with growing food shortages and other potential implications. Because it doesn't happen often, little is scientifically understood about rat floods. This lack of knowledge has been recognised, particularly by the United Nations Development Programme which recently commissioned a team of scientists to gather together all the existing knowledge. Academics were fielded from many of the nation's respected institutions, including Dhaka University [...]
Given the historical context of the last rat flood 50 years ago in the Mizo Hills of India, the authors of the report are concerned that growing civil unrest caused by a regional famine could inflame inter-cultural tensions in the CHT. The authors are also concerned that large dispersing populations of rats could cause a disease epidemic stretching beyond the CHT region. As the rat flood event is occurring in Myanmar, a country where bubonic plague is endemic, there is a risk of plague entering Bangladesh over the Burmese border through dispersing rodent populations. Without proper preparedness and scientific understanding and monitoring, an outbreak of plague could cause widespread panic in Bangladesh, leading to a national embargo and quarantine of the entire country, as similarly occurred to India during its plague outbreak of 1994, which is estimated to have cost India more than $3 billion in lost revenue. Furthermore, the event will lead to a shortage of bamboo throughout the country because the CHT forests will take several years to regenerate. It is not yet clear how this shortage of bamboo will affect businesses across the country.