THEY range from cacti with spines so soft they feel like hair, to tortoises so rare just one remains on earth.
The rich and fascinating variety of living things in the Galapagos islands has been revealed in its greatest-ever detail by researchers who, for the first time, have compiled a list of all the islands' 4,388 species.
The database has been complet
ed in the year of the 200th anniversary of the birth of Charles Darwin, whose revelations made many species on the islands – off Ecuador – famous.
As well as the finches and tortoises which helped Darwin form his theory of evolution – due to their unique characteristics which varied from island to island – a vast variety of other species live on the islands.
They too have evolved in isolation, meaning many have developed unique characteristics, and exist nowhere else on earth.
They range from rare seabirds, whales and mammals through unusual cacti and herbs to even snails. There are 178 types of plankton, 63 corals, 356 species of algae and 986 lichens and fungi.
Across the archipelago there are ten times more species than those that were identified by Darwin when he visited in the 19th century.
They include unique types of prickly pear cactus, which have developed into bizarre shapes and sizes in response to their location on the cut-off islands.
Some have evolved into trees, up to 12 metres high, and others have grown spines as soft as hair. Their fruits and flowers provide an important food for Darwin's famous finches.
Other species include a type of sea lion unique to the Galapagos, and the only species of penguin found in the northern hemisphere.
It is not only the smallest penguin in the world, it is also the only one that is known to breed in the tropics.
There is also Lonesome George – the sole remaining Pinta tortoise.
As well as native species, there are a growing number of invasive animals and plants on the islands, according to experts.
These include the little fire ant, one of the most aggressive invertebrate species ever introduced to the Galapagos. It has infested large areas and caused devastation.
The tiny insects attack baby birds and even tortoises with their powerful sting.
Other problems are caused by five species of alien blackberry. They form dense thickets up to four metres high, and compete with native species for light and water.
The scientists at the Charles Darwin Foundation, behind the vast database, say it will help them learn more about the ecosystem of the islands, which are under increasing pressure, particularly from growing numbers of tourists.
Frank Bungartz, one of the scientists involved, said: "When scientists look at an ecosystem, it's a multi-step process.
"First you see what's there. Then you want to know how it all fits together, and then you want to know how it has changed over time, and what the human impact has been. Only then can you do restoration work."
BACKGROUNDLand snails: 57 species exist only in Galapagos; 48 of them are endangered.
Galapagos penguin: The only penguin in the world that breeds in the tropics.
Rice rats: At risk of extinction due to competition from introduced brown rats and predation by feral cats.
Galapagos sea lion: Smaller than its closest relative, the Californian sea lion, and unique to the islands.
Prickly pear cactus: Six species found only in Galapagos.
Galapagos rock-purslane: A pink herb that is endangered due to over-grazing by goats.
Pinta giant tortoise: Just one remains, known as Lonesome George.
Little fire ant: An introduced invasive species that is causing devastation, and even attacks tortoises.
