Coconut Smack-Down: Rats vs. Crabs
Rising seas due to global warming could wipe Tuvalu, one of the world’s smallest and most remote nations, off the map in the next few decades, according to some scientists. The nine tiny islands in the Polynesian coral archipelago are pancake flat, no more than five meters above sea level at their highest point. In the present however, rats are more menacing because they are rampaging Tuvalu’s atolls and gnawing through the country’s chief export crop - coconuts. Coconuts and copra (dried coconut flesh from which coconut oil is made) are the islanders' main source of revenue. The rats are particularly fond of young green nuts and can leap a meter in the air from a standstill. Damage to the green nuts is put at over 60 percent.
The United Nations Food and Agriculture Organization has stepped in with a $200,000 ecologically-based pest management project due to downsize the marauding rat packs. The program will be implemented by a locally-recruited retired rodent management expert who will show coconut farmers how to dispose of the rats in an environmentally-friendly manner. An absolute priority is to safeguard the native population of young coconut crabs - a fast-vanishing species that is one of the wonders of the animal world.
Coconut crabs, also known as robber crabs - and sometimes nicknamed godzilla crabs are normally the size of small cats but can grow to 80 cm in size. The world’s largest land invertebrates, their huge claws are powerful enough to lift rocks weighting almost 30 Kg. As their name indicates their preferred food is coconuts, although - unlike the rats - they normally wait for the fruit to fall from the tree.
The FAO program will use recycled Australian pineapple cans containing suitably tasty baits treated with rodenticide. The cans will be strategically hung from wires to put them out of the reach of the young crabs - though not of the more agile black rat. Metal bands will be fastened around coconut palm trunks to prevent rats and crabs from climbing up. Similar projects elsewhere have resulted in production increases of up to 180 percent. (FAO, 5/8/06).
