"The Galapagos"… An unusual name that rings of mystery and science, explorers and pioneers, and more than anything, uniqueness. Where does this name come from? It comes from the very first visitors to this area, the Spanish. From the very beginning, human beings that stepped on these remote, inhospitable shores were astounded by the strange creatures, almost exclusively reptilian, that first met the eye. From the almost grotesque looking marine iguanas to the snakes, land iguanas and lizards, the creatures that were the most shocking were the unusual giant tortoises. The ones that would have been seen by these early visitors were no doubt those inhabiting the lower islands, which typically show the "saddle-backed" morphotype, and the Spanish word for saddle back then was "Galapagos" - thus the island's famous name.
But was it so strange to find these giant reptiles on an isolated archipelago such as the Galapagos? In general it is found that whereas mammals tend towards dwarfism on islands, reptiles tend towards gigantism. The list begins with the huge Galapagos tortoise, and includes both groups of endemic Galapagos iguanids. Another even more famous example of this tendency is the infamous Komodo dragon, that far outsizes even our lizards. Giant tortoises were not uncommon, and used to be found throughout the Indian ocean: in fact Darwin was not impressed by the Galapagos tortoises, because he just assumed that they had been left here by early pirates or whalers, and were originally from the Indian Ocean. The only other naturally occurring giant tortoise population that still exists to this day is that of the Aldabra Atoll, the last of many tortoise populations inhabiting remote islands in the area. The Galapagos tortoise is in fact now believed to have evolved from a small species of Chilean desert tortoise, and to have evolved its gargantuan size in situ.
All these areas have in the past been infested by sailors of many types, either pirates or worse predators (such as whalers). Unfortunately it was soon discovered that the flesh of the tortoise was excellent eating, and even more important: they contained their own water tanks, the bladder and the pericardium. In fact the tortoise can survive well over a year without food or water, a huge bonus in the era before refrigeration, when salted meat or fish could become pretty tedious. As a result, the giant tortoises of the world have become reduced to just two populations, and the Galapagos tortoises are in a serious predicament.
The Charles Darwin Research Station has been carrying on a very successful and vitally important conservation program for the tortoises, which has greatly enhanced their chance of survival. It was truly thrilling to see the young tortoises doing so well in their pens, and knowing that they are soon to be repatriated, and even more so to see these relictual creatures in their natural habitat, as we did this afternoon.
