Giant Tortoises of the Galapagos Islands
Most of the tortoises removed were female, since they were smaller in size, compared to males, and could be found more accessible in lowland areas, during the season, when eggs are laid These tortoises could be flipped on their backs and stacked in cargo, and survive for months, without food or water. This provided a source of fresh meat, during long duration’s at sea. Later in the 1800s, whaling ship crews and fur-sealers, hauled away giant tortoises for food and killed a number of tortoises for ‘turtle oil.’ Many of settlers on the Galapagos Island, had domesticated animals, such goats, pigs, dogs and other animals, which destroyed or had eaten tortoise eggs. Today, the estimated number of giant tortoises alive is 15,000 worldwide. Historical records have shown, thousands of giant tortoises were taken from the Galapagos, Mascarenes, Seychelles, and other islands.
There are fourteen subspecies of the Galapagos tortoise of which eleven still exist. Common types of giant tortoises, living in the Galapagos are Saddle-Backed: Distinguishable by raised shells, long necks and limbs. They are found in the lower drier islands, and are the smallest type of tortoises. The most famous, oldest (at least 80 years old), and remaining Saddle-Backed Tortoise, found on the Galapagos Island of Pintas in 1971, and given the name Lonesome George. During the past many years, researchers have been trying to mate Lonesome George with a female tortoise, which hopefully will produce, a new generation of Saddle-Backed tortoises. Last reported in 2003, Lonesome George weighed 350 pounds, and lives at the Darwin Research Station on Santa Cruz Island. Dome-Shaped Tortoise: Appear to have round shaped shells, very short necks and limbs. Found living in the upper parts of the islands, where plant growth is dense and thick. Intermediate: This type of tortoise is a combination of Saddle-Backed and Dome Shaped. Giant tortoises can keep growing for the first 30 – 40 years, and could live, more than 100 years. The oldest know tortoise on record lived 152 years.
Giant tortoises have unique behavior characteristics. They wake up 7 – 8 in the morning, and then lay in the sun, which warms their body. Then until four or five in the afternoon, spend grazing on a variety of plants, grass, vines, cactus fruit and other vegetation in large quantities. Food passes through their body, without being digested. At night – time, a tortoise will sleep in a snug depression in the ground, which helps conserve heat. A tortoise is capable of surviving without water for long periods of time, because of the capability to breaking down their body fat, which produces water. Muddy pools provide an opportunity for tortoises to bath. When a tortoise needs to remove ticks or parasites from their body, simple raise themselves up onto their legs, and stretch their necks, which provides the opportunity, for little birds to fly onto their body, and remove those pests. A tortoise will withdraw its head, neck and forelimbs into its shell for protection, when presented by a threat or predator.
Giant tortoises reach their sexual maturity, at the age of forty. Breeding season for tortoises, mostly during the rainy season, between January and August or sporadically during the year. Males have concave underside, which facilitates mating, from behind the female. Mating may last up to several hours, and males often give hoarse roars. After copulation, the female tortoise may travel several miles to find a dry and sandy area for her nest. She uses here hind legs to dig the nest and then lays her eggs inside. The female tortoise lay between two – sixteen eggs. Within the nest hole, she will place a mixer of urine and leaves, which will help to incubate the eggs, in the heat of the sun. Baby tortoises will hatch in four to six months. The sex of each hatchling determined, by the average temperature within the nest during incubation. Male tortoises will more likely be born, when the temperature is less than 28 centigrade, and females are born, when the temperature is above 29 centigrade.
In 1959, the Galapagos National Park and the Charles Darwin Foundation was established. Since 1965, The National Park strives to save the lives of tortoises. Tortoise eggs are collected and are delivered to the Charles Darwin Research Station, were they are incubated in a safe environment. The process of transporting tortoise eggs is done carefully, because each egg is kept in the same position, as it was laid, since the tiny embryo, soon attaches to the eggshell, where it begins to grow. The baby tortoises are kept in the research station until they are five years old, and then released on Espanol Island. At that age, tortoises are big enough to defend themselves, against predators such as dogs and rats. Since, the beginning of conservation efforts to increase the number of tortoises, nearly 2,000 have been returned to their island of origin.
In 1932 naturalist Charles Haskins, collected and presented to the Honolulu Zoo (Hawaii), specimens of Galapagos Tortoise. In 1954, the zoo had the first successful breeding of the Galapagos tortoise, which helped several zoos establish their own habitat for giant tortoises. Since, 1965, two males and twelve female tortoises, where transferred to the research station, for breeding. Also, the National Park authorized the killing of wild goats, which helped increase the vegetation for tortoises. Originally, in the 1950s these goats were released by fishermen, as an alternative food source, however these animals destroyed the vegetation, that tortoises required for food to survive.
