As you might have read a few days ago, the Houston Zoo’s Dr. Joe Flanagan has left for the Galapagos — specifically Pinta Island — to release 39 hybrid (but sterilized) Galapagos giant tortoises there. If you missed it, you can CLICK HERE to read all about it in the first of what will be many posts, sent from the field over the next several weeks. Here, we learn more about his mission and the giant tortoises.
Hybrid tortoises are the offspring of animals that were brought to the Charles Darwin Research Station (located in Puerto Ayora, Santa Cruz Island, Galapagos) back in the early 1960s. At that time, it was unknown which island the individual tortoises had come from as they were formerly pets that came to them from many places throughout Ecuador. When eggs were laid, they were hatched and reared in order to develop the needed skills in tortoise husbandry that the CDRS and Galapagos National Park (GNP) would use in restoring tortoise populations on other islands. Breeding in this group was halted in the mid 1970s, but the CDRS and GNP were left with a fair number of large animals that would need to be fed and cared for over the next 100 years!
A man named Wacho Tapia was working on an idea that would help restore Pinta Island’s habitat, and at the same time, reduce the amount of resources they had to invest in caring for those long-living giant tortoises. In November 2008, Wacho asked me, “Is it possible to sterilize giant tortoises?” The answer was yes. So last fall, I went to Galapagos with 2 great friends, and outstanding reptile surgeons, Steve Divers (University of Georgia), and Sam Rivera (Zoo Atlanta) to perform the surgeries to sterilize these 39 animals. Steve brought along a resident, Emi Knafo, and vet student Jason Norman to help with the procedures and to take advantage of this unique learning opportunity. We did all the surgeries in a busy week of learning and fun, staying busy with the tortoises from dawn til dusk. In the evenings we worked on our plans for the following days. As a group, we learned a lot from each other and from the project that was beginning to evolve.
We don’t want these tortoises to reproduce on Pinta because we still hope that some day a pure strain of tortoises can be released there to re-populate the habitat with the most appropriate inhabitants. If we later introduce fertile animals, we don’t want them to interbreed with the hybrid tortoises. So, now we have to be confident that none of the animals we transfer to Pinta at this time can breed. We also have to assure that they are not carrying any seed from plants that don’t belong on Pinta, and that they are free of parasites that wouldn’t be native to Pinta. For the past 2 months, “our” tortoises have been held in isolation pens and fed a diet lacking seeds. Their pens have been cleaned regularly to prevent the ingestion of any of the native vegetation from Santa Cruz Island. We’ve also administered antiparasitic medication to each animal twice. When I go down there next week, each animal will get an additional treatment to assure they are parasite free. and we can move on to the next step in the project to release them on Pinta Island.
Please check back tomorrow for another installment from Dr. Joe’s Giant Tortoise Adventure!
Written by Dr. Joe Flanagan
