After a short walk from the city center from Puerto Ayora we arrived at the Darwin Station, mainly installed to save the giant tortoise of this and some other islands but also as a museum with great and well presented information about regional biology. I’ll try to give some relevant information in short.
The Giant Tortoises:
We don’t know how they arrived on the islands we only know that they were here for a very long time. And on every island – depending on the kind of food growing there – a different subspecies developed. The shell of a tortoise on Pinta – where it is rather dry and the only food growing on trees or opuntia, developed to have a concavity on the front for better movement. Additionally those same tortoises have very long necks and longer legs than their brothers and sisters on islands with food on the ground.
This story is really sad. For a long time biologists believed that the Pinta Giant Tortoise (Chelonoidis nigra abingdonii) is already extinct when in 1971 somebody found one male specimen on the island. He was brought to the Darwin Station to protect him and named Lonesome George. They made big efforts to find a female specimen but didn’t and tried to partner him with a similar specimen from San Cristobal or Española. But George didn’t wanted to reproduce. Finally, it was to much pressure after all. He died – as the last of of his kind – in 2012.
Española Diego – The Tortoise Stallion
Do you believe that this extremely lazy looking guy has already reproduced over 2000 times? May I introduce you to Diego, the tortoise stallion. He is an Española Giant Tortoise and in the 60s there where only some specimen left: 12 females and 2 males. Biologists brought back Diego from the San Diego Zoo to the Galapagos Islands and with his more than 2000 children, the Española Giant Tortoise is today back to be self-sustaining.
Why have the tortoises been nearly extinct?
Well, they can survive for a very long time without moving and without a lot of food which makes them the perfect fresh meat for ocean expeditions, cruises and pirate ships. Some of them loaded more than 700 specimen on board (Darwins Beagle was well documented).
Darwin on the Galapagos Islands
In our mind the Galapagos Islands and Darwin are tightly linked although Darwin has stayed in the archipelago only for five weeks from September to October 1835. The Beagle, Darwins ship, was on its cruise for five years all together and headed to Tahiti afterwards. The tortoises are the most striking animals on Galapagos but the specimen that gave Darwin the idea for the evolution theory was a little bird later called the Darwin Finch which showed expressive signs of adaption to its individual environments.
Darwin didn’t publish his theory for a long time. First of all he was a very accurate researcher and never satisfied with his work and secondly he feared societies and churches reaction on it. But when a young scientist came up with very similar thoughts, some of his friends quickly urged and helped him to release it.
The biggest threads to natures balance on the Galapagos Islands
The Giant African Snail
They damage crops, they carry diseases and they reproduce like hell.
Introduced by colonial ships they reproduce by seed, branches and roots and damage huge natural or agricultural areas.
Philornis downsi Flies
Which lay there eggs in birds nests and their larves attack the baby birds.
Iguanas: Signs of evolution
The black marine iguanas which you can find today all over the archipelago, are a native product of the Galapagos Islands. They learned swimming during their evolution, because there was not enough food on the volcanic land. They can shrink there body size if there is not enough food and they can stay under water for a very long time, but when you see them lying around in the sun they are reheating. Life of a saurian.
There is one subspecies called Amblyrhynchus cristatus godzilla and you already know whom he resembles …
The Santa Fe Iguana tolerates finches to remove their ticks.
The Pink Iguana, Conolophus marthae, was only found around Wolf Volcano and its approximately 200 specimen exist only in an area of 25 km2.
And the population of the Yellow Iguana, Conolophus subcristatus, is growing now that wild cats and dogs are under control.