Galapagos Tortoises on the Rebound

Galapagos giant tortoise Geochelone elephantopus
A dome-shelled Galápagos giant tortoise, Chelonoidis nigra
Image from Wikimedia Commons

In the 1700’s when the world was still an unknown place, sailors landed on the Galapagos Islands. But what they did not realize is that although they meant no harm, they brought with them rats and diseases from their home country. The rats and diseases destroyed the population of the giant tortoises over time by eating the eggs of the adult tortoises. About 250 years later, in the 1960’s, environmentalists took the tortoise eggs to different place where they could incubate, grow, and live without the threat of rats. When they became 5 or so years old, they would return them to the island to live on their own. These new tortoises laid eggs, but these were also eaten by the rats. The incubation method wasn’t fixing the entire problem, and there hadn’t been a naturally hatched egg on the island since the 1700’s.

Galapagos egg and hatchling
A Galapagos Tortoise Hatchling
Image from Wikimedia Commons

In 2012 biologists decided to drop rat poison over the entire island in hopes that the rat population would dwindle and die off and the tortoises could survive. This worked, and the island was declared rat free not too long ago. Recently, there have been 10 spotted hatchings and declared that there were up to a couple hundred more that were not spotted. Now, there estimates to be around 500 tortoises on the island, and plenty more to come because of the rat problem being removed. The Galapagos islands are the only place in the world that the tortoises naturally call home, they have a close relative called Aldabran Giant tortoise who also gets its’ name from the island in which it lives which is on the complete other side of the world. Both of these tortoises are highly endangered and very rare. But, with the recent breakthrough on the rat problem there is no reason why they could not continue to multiply and break out of the cusp of extinction.

One of Darwin’s earliest test subjects was in fact the Galapagos giant tortoise and he made several accounts that there were subtle differences between the tortoises from each of the different islands of archipelago. Although, he did not recognize it at first, it later helped to prove his theories about adaptations and mutations helping each organism survive. Each island had slightly different obstacles to overcome and necessary adaptations to make in order to survive and reproduce. In this case, the tortoises were not able to make a change in their eggs or where they laid them so the rats could not eat them. Instead, his theory of natural selection would have taken over and the species would have died off for not being able to make an adaptation. But, the humans helped the tortoises out, and they are able to live and prosper now. And, although the process did not run its course in this case, there will be other life threatening challenges they have to face and if they cannot make a change, the humans will have to bail them out, or they will die.

About Mr. Mohn

Biology Teacher

This entry was written by Nick Meh. and tagged . Bookmark the permalink.

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