Galapagos Giant Tortoise

The Galapagos Giant Tortoise plodded slowly up to me. It was approximately 100 years old, three hundred pounds, and reached above my knees. We saw many more large tortoises. They all moved to the same slow rhythm while wading to keep cool, feast on piles of leaves, and wandered about. At the two tortoise centers we visited, I learned about their history.

It all starts when a pair or more of tortoises, smaller and with a shorter neck than those of today, somehow got on a raft of trees or other organic non-manmade material and was blown out to sea. It landed on the Galapagos. Slowly the tortoises evolved to match their new surroundings. The tortoises on the mainland took a completely different evolutionary path and barely resemble Galapagos Tortoises. In the seventeenth, eighteenth and early nineteenth centuries, buccaneers, whalers, and other ships passing by stopped at the islands, including Charles Darwin on the HMS Beagle in 1835. These visitors collected the tortoises because they can survive for weeks without food or water; therefore, sailors would have fresh meat at sea by keeping them alive in the bilge. Taking tortoises continued for many years and also included a time when they were taken for the tortoise oil. From 1946 to 1959, there was a penal colony on Isla Isabela. The people in charge killed lots of tortoises to feed the prisoners because it was cheap and fatty so the prisoners did not need much of it to live.

As people came to the islands, they brought animals that escaped such as dogs, cats, cattle, donkeys, horses, goats, and even ants made it into the wild. These animals began to hurt the turtle population. Dogs could dig up eggs and break the relatively soft shells of baby tortoises. Cats also dug up eggs. Cattle, donkeys, horses, and goats would trample nests and destroy eggs and eat the low vegetation the tortoise, especially the babies, depends on to eat. They also drank the water pools that tortoises relied on to cool themselves and to drink. Ants would dig down to nests and eat the eggs. In three generations, the population of tortoises went from 300,000 to 200.  In the wild, even with nobody hunting them, the tortoises did not stand a chance; they needed help. In 1968, killing tortoises was made illegal and people started to try to help the tortoises by raising them in safety some number of years after that.

The tortoises seem to thrive in captivity, unlike many other animals that have a shortened life expectancy in captivity. Caring for and protecting these slow animals is not complicated; they need food, water and enough space to wander. In contrast, raising them is very complex. People need to find the nests in the enclosures, which keep other animals out, before the ants find them. Once a nest is found, they dig it up at the speed and precision of an archaeologist. Once they reach the eggs, they are marked to show which side is up and where in the nest each one goes. If an egg is turned upside down, it dies. And if it is placed in the wrong spot on the nest, many of the others will die.

 

This is true because tortoises dig their way up when they hatch. If another egg is in the way, they smash it. To prevent this, the eggs hatch in an order so that the ones on top hatch first and the ones on the bottom hatch later. The temperature of a nest decides whether the tortoises will be male or female. Only females are raised in captivity. Males are captured as they mate many times each season and females mate only once a year, so you need more females.

When they are hatched, the tortoises look exactly like the giant ones, but smaller.

 

They are protected until they are large and their shells are hard. They are kept in wooden boxes that give them enough space to walk around, eat leaves and bask in the water holes in each box. Each box holds a group of babies from the same nest. The boxes are raised off the ground to keep the ants out, and have a locked fence top to protect them from predators, birds, or any unauthorized people. When we saw the full grown tortoises, they were eating huge leaves and standing next to a watering hole; the small tortoises stood in their cages eating leaves next to a watering hole. The only difference was everything was shrunk a good bit and the giant ones were surrounded by natural trees and plants whereas the small ones had no vegetation around them except the food. Each baby had a number written on its back. As they grow, everything about them is carefully recorded. Size, how much food the group in the box has eaten per day, growth speed, and health are all documented. As they get older, they are transported about twenty feet to an enclosure full of five to nine year old tortoises. Slowly, they move to each new enclosure until they are released into the huge park and hopefully, in a few generations, into the wild.

 

In 1998, 18 adult tortoises, a combination of male and female, from one particular place on Isla Isabela were captured and brought to the San Isabela Tortoise Center because that specific variation was near extinction. They produced 200 successful eggs in the first two years and, today, hundreds of baby tortoises live in enclosures nearby because of them. The tortoise stations have an 85% success rate, which is exceptional. It took 200 years to nearly wipe out the tortoises. It looks like it will take about the same amount of time to restore them to their previous population.

This one looks like he knows something I don't know. And given that he is probably close to 100 years old, he certainly does!

I loved walking with the tortoises. Some seemed mildly interested in me, as long as they were not eating. On San Cristobal, a tortoise walked right across the path and took off at what looked like a wind sprint for it. It was chasing a female. For males to mate, they have to catch the female. I strolled slowly beside it watching its sprint. In the end, the female escaped. No wonder it is going to take so long to repopulate! – Porter