Sir: Sean O'Grady (Barometer, 10 October) comments on the rafting of iguanas between West Indian islands. This is not a new phenomenon.
Prior to the closing of the Central American isthmus the West Indies was open to the Pacific and rafts of red mangrove carried organisms out into the Pacific currents. This is how the ancestors of the three endemic Galapagos iguana species are believed to have reached those remote islands off the Ecuadorian coast.
Even more surprisingly, the Southern Equatorial Current is believed to have carried rafts of West Indian red mangrove westwards across the Pacific before turning south towards Fiji and Tonga. This is believed to be the route followed by the ancestors of the two rare Fijian iguanas and three western Pacific boas which are the only representatives of their families in the Melanesian/Polynesian region otherwise inhabited by agamas and pythons.
Curator of Reptiles
West Midland Safari Park