September 29, 2011 § Leave a comment
The Fausto Llerena Breeding Center at the Charles Darwin Research Station has just opened two new pens for small Galapagos Tortoises. The pens approximately 1000 square meters in size will be home to tortoises two years of age who will spend two more years at the center before being released on their home island.
In one pen there are 180 pre juvenile tortoises from the species Geochelone ephippium and Geochelone hoodensis which originate from Pinzon and Española. The second pen houses 117 tortoises (Geochelone darwini) from the Island of Santiago.
While at the breeding center the park rangers care for the tortoises, feeding them twice a week, keeping the pen clean as well as monitoring their growth every three months.
The Charles Darwin Research Station and the Fausto Llerena Breeding Center is located on the island of Santa Cruz and is a frequent stop for visitors of to the Galapagos Islands. The Breeding Center is currently home to 925 young tortoises and 70 adult tortoises including Lonesome George – famous for being the last of the Pinta Tortoises.
May 27, 2010 § 2 Comments
Galapagos tortoises are the enigmatic symbol of the Galapagos Islands. Online readers have picked the Galapagos Tortoise as their favorite animal of these enchanted islands. For many visitors viewing these gentle giants is considered a “must” part of their vacation.
Giant tortoises first arrived in the Galapagos many millennia ago. It is thought they originated in South America and made their way across the Pacific Ocean by floating on a piece of wood. Arriving in the Galapagos the tortoises found their new home rugged and harsh, yet tortoises are able to survive long periods of time without food or water making them uniquely qualified to become the dominate grazing animal on these islands. At one time 15 distinctive sub species of Galapagos Tortoise existed – today only 11 remain.
Each of the sub species evolved differently depending on the island where they lived. You only need to take a look at a tortoise to quickly determine the type of environment existed on the island where the tortoise evolved.
Tortoises that evolved on the larger islands – like Santa Cruz or the Alcedo Volcano on Isabela benefited from the lush plant life and grew to be the largest of the species. They had plenty of food and did not need to travel great distances. They can be identified by their larger size, domed shells (making it easier to push brush out of the way) and by their shorter legs and neck.
Tortoises that came from smaller drier islands had a saddleback or flatter shell with longer legs and a longer neck making them capable of traveling greater distances. The main staple of tortoises from these areas was the pad of the opuntia cactus and the long necks allowed the tortoises to reach their meal.
Tortoises are quite elusive in the wild, and to help preserve the species the national park has made it off limits to visit many areas on various islands where the tortoises roam free. There are four islands in the Galapagos in which visitors can view tortoises: Santa Cruz, San Cristobal, Floreana and Isabela.
The most popular of these places is on the island of Santa Cruz. For visitors traveling to a Galapagos Cruise the Charles Darwin Research Station is part of every itinerary. The Darwin Station, home of the Galapagos National Park and the Darwin Foundation is the heart of the great conservation and preservation efforts being made in the islands.
Established in 1969 these organizations quickly realized that the remaining species of tortoises were all endangered of becoming extinct. They rapidly set up a tortoise breeding and rearing program in order to protect and repopulate the species. Tortoises were transported from their island to pens at the Darwin Station where they were able to breed and their eggs. The eggs were put in incubators where they could hatch without the concerns they would have in the wild.
During early years of life, young tortoises are in constant danger primarily from introduced species. Rats feed on tortoise eggs. The shells of hatchlings are fragile and the hooves of feral goats and donkeys can easily damage the shell and kill young tortoises. At the breeding center, there are pens for tortoises of different ages allowing them to develop without these threats until they were old enough and their shells strong enough to be released back into the wild.
The most famous resident of the Darwin Station is Lonesome George. Discovered in 1971 George is noted as the last remaining tortoise on the island of Pinta. A rather flat island, it was a favorite place for passing boats to fill their hulls with fresh tortoise meat. At the time George was discovered it was thought his species was extinct. Scientists were delighted to have found a remaining tortoise and plans began right away on how best to help George and his species survive. Having him remain on Pinta had complications as feral goats overrun the island and were devastating the island’s vegetation and limiting the food supply available for George. The solution was to move him to the Darwin Station, which would provide a safe haven while they searched for a mate and way to continue his line.
Traveling to the highlands of the island is the best place in Galapagos to see these tortoises roaming free. From June to December during the dry cooler months the tortoises travel to the highlands in search of the area’s water and juicy plants. During these months the tortoises can be found in the area near Santa Rosa. The tortoises mate and then the female tortoises depart to lay their eggs. Male tortoises remain here year round enjoying the muddy water of the lagoon and the many plants in which to eat.
On the island of San Cristobal, visitors can travel to the highlands to visit Cerro Colorado a recently built tortoise reserve not far from El Junco Lagoon. Tortoises of San Cristobal were endangered from feral animals, so the tortoise preserve was established as a walled area that protects them from other species. Coming here visitors can enjoy a stroll along the boardwalks and grated trails seeing San Cristobal tortoises, local plants and a variety of birds including the endemic Chatham Mockingbird, Yellow Warbler and Darwin Finch.
Making your way to the island of Floreana provides yet another opportunity to view San Cristobal tortoises. Floreana was a favorite island of sailors and as tortoise meat was an easy supply of food that would last for months on board their ships, Floreana Tortoises were collected to a point of extinction. In a rock wall area in the highlands of Floreana you’ll find the tortoises that were brought here by members of the Wittmer Family (who built a small hotel on the island). The tortoises were viewed as a way to encourage visitors and they were left to roam the grounds of the hotel for the enjoyment of tourists. As the tortoises were not natural to the islands and are considered now to be a mixed breed rather than pure-breed the National Park Service established a tortoise pen in the highlands of Santa Cruz where these tortoises can be seen today.
Isabela is my favorite place to see Galapagos Tortoises. The largest of the islands, Isabela is home to 5 distinct sub species of Galapagos Tortoise. The National Park and Darwin Foundation set up a breeding center for Isabela tortoises just outside the town of Puerto Villamil. A nice walk passing by flamingo lagoons takes you to this the tortoise center where you can see several species of tortoise next to each other. It’s here where you can best identify the environment in which the tortoise evolved by looking at its size and the shape of its shell.
The tortoise breeding programs both on Santa Cruz and on Isabela have been very successful. Many of the tortoises from both programs have been released into the wild allowing them to live the lives they were meant to live. On Isabela you can see these newly free tortoises ranging in age from 5 years to 25 years roaming free in an area near Wall of Tears. Walking along the paths through the mangroves you can encounter these future giants walking along eating the smaller plants and enjoying the waters of small pools.
Read our blog on Galapagos Tortoises and the Evolution of Extinction
March 19, 2010 § 4 Comments
When you think of Galapagos, the first two thoughts that come to mind are Charles Darwin and giant tortoises. The giant tortoise is the iconic symbol of these islands. The name Galapagos come from a Spanish world for saddle – referring to the shell of these gentle giants. The national park uses an image of the giant tortoise as its logo. Whenever you see information about the Galapagos – you see pictures of the beloved giant tortoise.
The world’s largest tortoises, Galapagos Tortoises have a lengthy 150-year lifespan. Male tortoises are known to grow to be over 600 pounds. The archipelago was never attached to a continent and all the plants and animals, which arrived in the Galapagos, did so by either swimming, flying or floating. The journey across the ocean was too difficult for grazing mammals that dominate the grasslands of other parts of the world, and thus the slow moving tortoise reigned as king for thousands of years.
At the time of Charles Darwin’s visit in 1835, it was thought that 250,000 tortoises and 12 subspecies existed here. It was the comments regarding the tortoises from the local vice-governor, which first dismissed by Darwin, would later come to inspire him:
“I have not as yet noticed by far the most remarkable feature in the natural history of this archipelago; it is, that the different islands to a considerable extent are inhabited by a different set of beings. My attention was first called to this fact by the Vice-Governor, Mr. Lawson, declaring that the tortoises differed from the different islands, and that he could with certainty tell from which island any one was brought. I did not for some time pay sufficient attention to this statement, and I had already mingled together the collections from two of the islands. I never dreamed that islands, about fifty or sixty miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case. It is the fate of most voyagers, no sooner to discover what is most interesting in any locality, than they are hurried from it; but I ought, perhaps, to be thankful that I obtained sufficient materials to establish this most remarkable fact in the distribution of organic beings.”
Darwin and his shipmates aboard Beagle viewed tortoises much in the same way as the pirates and whalers, tortoises were something to be exploited. The members of the Beagle harvested 30 tortoises from the islands, which they ate on their way home.
Over the past few centuries the systematic harvesting of tortoises for meat, oil, as well as the introduction of new species dwindled the population down some 90% from what it was in during Darwin’s visit. Both the Floreana and Pinta tortoises are noted as extinct and all of the remaining 10 species of Galapagos Tortoise are listed as endangered species.
In 1959, 100 years after the first publishing of Darwin’s On the Origin of Species the Galapagos Islands became as a national park. The park service together with the Darwin Foundation has made remarkable steps over the past 50 years towards the preservation, conservation and restoration of native species.
Perhaps the best example of their efforts is the story of the Espanola tortoise. At one time there were at least 3000 native tortoises on the island of Espanola. However Espanola is one of the flattest and most accessible of the islands, making it a favorite place for passing ships. As a result by 1965 there were just 14 remaining tortoises living on Espanola – 2 males and 12 females. The tortoises were transferred to the Charles Darwin Research Station on Santa Cruz. A third male was then discovered at the San Diego Zoo. In the 1970’s the tortoise-breeding program began. From the brink of extinction, of 15 tortoise the program has been a success and today nearly 1500 Espanola Tortoise have been repatriated to their native island.
With the success of the Espanola program stopping the extinction of other species proved to be more problematic. In 1971, Lonesome George was discovered on the Pinta. He has the unique distinction of being is noted as the last remaining of his species. George was relocated to the Darwin Station and scientists began work on the question how to keep the Pinta Tortoise from becoming extinct. Two females from Wolf Volcano on Isabela were placed in the pin with George. These females were selected as they were found to be the genetically closest relation to George and though any off spring produced would not pureblood – the species would some how continue.
For years George showed little or no interests in these females. But in 2008, the national park announced both of Geroge’s companions laid eggs. The world awaited news if the Pinta race had been saved. At the end of the year it was announced none of the eggs were viable and their search for how to save the species continued.
In 1994 a team of Yale Scientists began the Galapagos Tortoise Genetics Process. The group went to Isabela and took blood samples from 27 tortoises living high on the Wolf Volcano. Some 2000 tortoises are thought to live in and around Wolf. These tortoises are of significant interest, as tortoises here, resemble more than one subspecies. Normally each group of tortoise will either have a domed shaped shell (similar to the tortoises of Alcedo or other parts of Isabela) or a saddleback shaped shell (similar to Lonesome George) depending on the environment where they live. Yet near Wolf, tortoises can be found with both domed and saddleback shells.
Over the next decade the genetics team began collecting DNA samples from the tortoises in not only in Isabela, but also began samples from tortoises at the Darwin Station, around Galapagos, and tortoises held in captivity all over the world. On Pinta they found they took DNA samples from the remains of 15 tortoises and they cataloged the information to gain a better understanding of the species.
As they began to review their database, the impossible seemed to be possible. First they believe they have discovered a second pureblood Pinta tortoise. A Tortoise known as Tony, thought to be approximately 50 years of age is living at the Prague Zoo – from all current data Tony appears to be the same exact subspecies as George.
As they sifted through the DNA information they discovered the reason the Wolf tortoises appeared to resemble more than one subspecies. Isabela and the area near the Wolf Volcano was often the last stop for pirate ships in Galapagos. It appears that these ships collected tortoises on other islands during their stay only to discard them here. When testing the DNA samples, several of the tortoises living on Wolf were found to be first generation hybrid Pinta tortoises – tortoises born to mothers from Isabela and fathers from Pinta. This discovery meant that some of the tortoises living on Wolf were 50% the same genetic subspecies as Lonesome George. This information provided new hope that by further investigation a pureblood or half-blood female Pinta tortoise can be found – and the Pinta race can survive.
The genetic team seemed to have uncovered a miracle – still there were more surprises to realize. The research discovered descendants of the extinct Floreana Tortoise. The Floreana subspecies became extinct during the early 20th century due to human activities, and unlike Lonesome George no known examples were known to have survived. Yet, the DNA research uncovered 9 tortoises with high percentage of Floreana genome (up to 94%) and they believe 1 tortoise may even be pureblood. Of the tortoises identified of being from Floreana 6 are female and 3 are male all of which are currently residing at the breeding center in Santa Cruz.
Drawing from the success of the Espanola breeding program these new findings of the Genetics team, man may now be able to make up for some of their previous wrong doings. What was once extinct may not be extinct in the future. It’s all just a matter of time with the help of science and mother nature.