AbstractThe Republic of Trinidad and Tobago (commonly referred to as Trinidad), is at the southern end of the Caribbean island chain, from which it is geologically distinct, since it lies on the continental shelf of South America in close proximity to Venezuela (Figs 1,2). The joint population is about 1·3 million, of whom all but some 50000 live in Trinidad, which at 4830 sq km is much larger than Tobago (300 sq km). Trinidad was a Spanish possession for three centuries before being taken over by the British in 1797: Tobago, by contrast, was not colonised by Spain. It has a most varied history, being ruled at various times by France, Holland and Britain, by whom it was finally recaptured in 1803. The two islands formed a combined colony in 1889 and, still linked, became independent in 1962.