Desert tortoises are a keystone species, which means they have a higher influence over their ecosystem than other species. Many other species use their burrows and benefit from having desert tortoises around, including the Gila monster, collared peccaries, roadrunners, and burrowing owls. They eat a variety of grasses, shrubs, cacti, and wildflowers, and get much of their water from succulents.
Desert tortoises rely on areas with high plant species diversity both for food and protection from weather and predators. However, fires can easily destroy their desert habitat, which is not adapted for fire. When fires are more frequent, they can turn thriving desert landscapes into nonnative grasslands.
Desert tortoises are built to thrive in their desert environments. They can fully retract their heads and legs inside the shell when disturbed, protecting the softer body parts from predators. Although mortality is high for young tortoises, once they reach adulthood desert tortoises are rarely killed by predators.
Their front legs are slightly flattened so they can easily dig into desert sand and dirt and build shelters to keep warm on cold desert nights. They stay in these burrows in a light hibernation through the coldest part of winter, occasionally emerging if the weather is nice. Desert tortoises also use their burrows for temperature control when it gets too hot in the summer.
Desert tortoises are usually solitary, but sometimes they share burrows. When males come across each other, they might fight for dominance by trying to flip one another over. Males are larger than females and can be identified by curved horns on the lower shell, beneath the neck. Once they reach adulthood, desert tortoises can live between 30-50 years in the wild, and sometimes up to 80 years. Unfortunately, due to habitat destruction desert tortoises are struggling for survival.
Desert tortoises are threatened by predators, drought, fire, and human activities such as shooting, collisions with cars, off-road vehicle use, disease from introduced domestic tortoises, and overgrazing. However, habitat loss is one of the biggest threats facing the desert tortoise today.
Invasive grasses can degrade desert tortoise habitat. Combined with fires, deserts can be turned into nonnative grassland. Desert tortoises are not adapted for this type of environment and struggle to survive. Invasive grasses can be carried on the wheels of off-road vehicles, which further degrate their habitat.
Roads can fragment desert tortoise habitat, making it difficult for individuals to find each other to breed. Roads also are a source of desert tortoise deaths because they can't move fast enough to get out of the way of a car.
With the establishment of the Galapagos National Park and the Charles Darwin Foundation in 1959, a systematic review of the status of the tortoise populations began. Only 11 of the 14 originally named populations remained and most of these were endangered if not already on the brink of extinction. The only thing saving several of the populations was the longevity of tortoises, keeping some old adults alive until conservation efforts could save their species.
The taxonomy of giant tortoises has changed over the decades since they were first named. Today the different populations are considered separate species of the genus Chelonoidis. There are currently 15 species. Giant tortoises were native to each of the big islands (Española, Fernandina, Floreana, Pinta, Pinzón, San Cristóbal, Santa Cruz, Santa Fe and Santiago) as well as the five major volcanoes on Isabela Island (Wolf, Darwin, Alcedo, Sierra Negra and Cerro Azul). Two species have been identified from Santa Cruz. Tortoises are now extinct on Fernandina (due to volcanism), Floreana, Santa Fe and Pinta (due to exploitation). Pinta Island had a single known tortoise, Lonesome George, who lived until June of 2012 at the Tortoise Center on Santa Cruz where he spent the final 40 years of his life. A taxidermy specimen of Lonesome George is now on display at the Tortoise Center.
Galapagos tortoises are herbivorous, feeding primarily on cactus pads, grasses, and native fruit. They drink large quantities of water when available, which they can store in their bladders for long periods of time.
Tortoises breed primarily during the hot season (January to May), though tortoises can be seen mating any month of the year. During the cool season (June to November), female tortoises migrate to nesting zones (generally in more arid areas) to lay their eggs. A female can lay from 1-4 nests over a nesting season (June to December). She digs the hole with her hind feet, then lets the eggs drop down into the nest, and finally covers it again with her hind feet. She never sees what she is doing. The number of eggs ranges from 2-7 for saddle-backed tortoises to sometimes more than 20-25 eggs for domed tortoises. The eggs incubate from 110 to 175 days (incubation periods depend on the month the nest was laid, with eggs laid early in the cool season requiring longer incubation periods than eggs laid at the end of the cool season when the majority of their incubation will occur at the start of the hot season). After hatching, the young hatchlings remain in the nest for a few weeks before emerging out a small hole adjacent to the nest cap. The sex of a tortoise is determined by the temperature of incubation, with females developing at slightly hotter temperatures.
In 1959, the status of the extant populations of land iguanas was considered good. Then in 1975, two populations on different islands (Cerro Cartago on Isabela and Conway Bay on Santa Cruz) were decimated in less than six months by feral dog packs. Unlike tortoises, adult iguanas are not predator-proof. Saving them meant removing them from their natural habitat until dogs were eliminated.
Unlike tortoises, the young land iguanas could not be repatriated to their original habitat unless the introduced predator problem was solved. Dogs eat adults as well as young iguanas, while cats eat only young animals. Once feral dogs had been eliminated on both southern Isabela and northwestern Santa Cruz, iguana repatriations were generally successful.
Lasiurus cinereus, the Hoary Bat from North America, is light brown with white fur tips, eats insects, and tends to prefer roosting in Mangrove trees or scrub bushes during the day. It is quite widespread and is found on Santa Cruz, San Cristóbal, Isabela, Santiago, and Floreana Islands.
Lasiurus brachyotis is found on Santa Cruz and San Cristóbal in the highlands and coastal zones, and it is believe to migrate seasonally between the two zones. This bat forages near the ground while the Hoary Bat forages higher in the trees and air, which explains why they can coexist. L. brachyotis is believed to be closely related to the Red Bat of South America.
Although the smallest and least often seen by humans in Galapagos, Red-footed Boobies are the most abundant of the three species. However, since they feed far out to sea, they nest in the outermost islands with access to open ocean and lay a single egg. While the Blue-footed and Nazca Boobies nest on the ground, Red-foots nest in trees and shrubs. The Red-foots also have two color phases, the large majority (95%) with a brown body and the rest with a white-and-black body.
The World Turtle, also called the Cosmic Turtle or the World-bearing Turtle, is a mytheme of a giant turtle (or tortoise) supporting or containing the world. It occurs in Hindu mythology, Chinese mythology, and the mythologies of the indigenous peoples of the Americas. The comparative mythology of the World-Tortoise discussed by Edward Burnett Tylor (1878:341) includes the counterpart World Elephant.
Brewer's Dictionary of Phrase and Fable lists, without citation, Maha-pudma and Chukwa as names from a "popular rendition of a Hindu myth in which the tortoise Chukwa supports the elephant Maha-pudma, which in turn supports the world".
There was once a king who was very powerful. He had great influence over the wild beasts and animals. Now the tortoise was looked upon as the wisest of all beasts and men. This king had a son named Ekpenyon, to whom he gave fifty young girls as wives, but the prince did not like any of them. The king was very angry at this, and made a law that if any man had a daughter who was finer than the prince's wives, and who found favour in his son's eyes, the girl herself and her father and mother should be killed.
Now about this time the tortoise and his wife had a daughter who was very beautiful. The mother thought it was not safe to keep such a fine child, as the prince might fall in love with her, so she told her husband that her daughter ought to be killed and thrown away into the bush. The tortoise, however, was unwilling, and hid her until she was three years old. One day, when both the tortoise and his wife were away on their farm, the king's son happened to be hunting near their house, and saw a bird perched on the top of the fence round the house. The bird was watching the little girl, and was so entranced with her beauty that he did not notice the prince coming. The prince shot the bird with his bow and arrow, and it dropped inside the fence, so the prince sent his servant to gather it. While the servant was looking for the bird he came across the little girl, and was so struck with her form, that he immediately returned to his master and told him what he had seen. The prince then broke down the fence and found the child, and fell in love with her at once. He stayed and talked with her for a long time, until at last she agreed to become his wife. He then went home, but concealed from his father the fact that he had fallen in love with the beautiful daughter of the tortoise.
But the next morning he sent for the treasurer, and got sixty pieces of cloth and three hundred rods, and sent them to the tortoise. Then in the early afternoon he went down to the tortoise's house, and told him that he wished to marry his daughter. The tortoise saw at once that what he had dreaded had come to pass, and that his life was in danger, so he told the prince that if the king knew, he would kill not only himself (the tortoise), but also his wife and daughter. The prince replied that he would be killed himself before he allowed the tortoise and his wife and daughter to be killed. Eventually, after much argument, the tortoise consented, and agreed to hand his daughter to the prince as his wife when she arrived at the proper age. Then the prince went home and told his mother what he had done. She was in great distress at the thought that she would lose her son, of whom she was very proud, as she knew that when the king heard of his son's disobedience he would kill him. However, the queen, although she knew how angry her husband would be, wanted her son to marry the girl he had fallen in love with, so she went to the tortoise and gave him some money, clothes, yams, and palm-oil as further dowry on her son's behalf in order that the tortoise should not give his daughter to another man. For the next five years the prince was constantly with the tortoise's daughter, whose name was Adet, and when she was about to be put in the fatting house, the prince told his father that he was going to take Adet as his wife. On hearing this the king was very angry, and sent word all round his kingdom that all people should come on a certain day to the market-place to hear the palaver. When the appointed day arrived the market-place was quite full of people, and the stones belonging to the king and queen were placed in the middle of the market-place. 2b1af7f3a8