The remoteness of the Galapagos Archipelago, 600 nautical miles from the mainland of Ecuador, has made it an exceedingly difficult place to colonize. Not only did its inhabitants have to cross great distances at sea but also subsequently seek out a living in this arid, inhospitable place. It is in fact estimated that the whole flora and fauna of the islands can be accounted for by just one successful arrival and establishment every 10,000 years or so! Due to these problems of arrival and establishment, there tends to be a very disharmonic distribution of species here, meaning an over-representation of some animal groups, notably reptiles which are supremely well adapted to these harsh conditions, and an under-representation or total absence of others.
Having reached the Galapagos, the few creatures that made it then evolved in complete isolation from their parent populations and in total absence of several important components of their usual ecosystems. This led to some rather “freakish” features in both the morphology and behavior of these island inhabitants, notably the unusual “tameness”, or ecological naiveté, of all these creatures that have evolved in the absence of all major predators.
“I then walked up and pulled it by the tail; at this it was greatly astonished, and soon shuffled up to see what was the matter; and then stared me in the face, as much as to say, ‘What made you pull my tail?’” – Charles Darwin, on encountering a Galapagos land iguana.
These surprising creatures used to be widespread in the drier parts of six of the central and western islands, though their numbers have been severely reduced by the introduction of such creatures as cats and dogs, mammalian predators that wreak havoc in this innocent world. Their numbers are still healthy in certain areas, and recovering in others thanks to the huge efforts of the Charles Darwin Research Station in restoring these threatened populations. A new exhibit opened in the station allows visitors to now get a good look at these unique iguanas, who live contentedly here in their natural habitat, notably areas covered in the giant Opuntia cactus trees. This important program has allowed several young iguanas to be reintroduced into their homelands, now once more safe from threats.
