Anyway, the WHO sprayed DDT liberally in the Dayak villages of the Sarawak interior. Initially, this campaign was considered a success as mosquitoes were killed and the malaria rate dropped. Then authorities were hit by two mystery complaints. The first was very bizzare. The Dayak villages consisted of longhouses which accomodate several families and which were covered by a thatch roof. The villagers complained that their roofs were collapsing exposing whole communities to the elements. Although puzzled, the authorities were forced to act quickly and sent in corrugated metal sheets to be used as roofing material.
Before, they could even take a breather, they were surprised by the outbreak of plague and reports of famine as grain stores were decimated by a large invasion of rats. The authorities urgently investigated the matter and called the Royal Air Force for help. Citizens were also asked to donate cats and to help build special cat baskets. Operation “Cat Drop” was carried out in which hundreds of cats were parachuted by the RAF onto interior villages. This reinforcement of cats eventually solved the problem.
The Day They Parachuted Cats on Borneo by Charlotte Pomerantz relates this true story in the form of a rhyme. It is also featured in an article by Gordon R. Conway in The Careless Technology: Ecology and International Development (1972) and a first-hand account of “Operation Cat-drop” is given by Tom Harrisson in the journal Animals published in 1965.
What transpired in the jungles of Borneo is a clear example and a cautionary tale that man does not know enough about the inter-connectivity of the web of life and many of our actions to address a single problem have often unexpected reprecussions. The DDT did infact kill the mosquitoes and also other insects in the jungle which were non-target species. One of which was a jungle wasp. These wasps in turn played the important role of keeping a certain caterpillar population in check by laying eggs on the caterpillar and when the larvae hatch out, the larvae feed on the caterpillar, killing it. When the DDT killed the wasp, the caterpillar population boomed and as the caterpillar fed on the roof thatching, the roofs started to collapse.
At the same time, the geckos which are a type of lizard which feed on insects were having a great time because it kept finding dead insects everywhere. However, as they ate, the DDT levels in their bodies continued to rise. The cats in the village in turn often catch and eat the geckos. Soon, all the cats died of poisoning. With the cats gone, the rats came out to play. Their population boomed, leading to the destruction of grain stores and the spread of plague. A situation that was only reversed by the airborne drop of cats over Borneo.
A strange but true tale and a warning to man to stop messing with the world’s complex and balanced web of life. I did not even mention how all these imported cats caused a great upset to the indigenous squirrel population!