The Galápagos Tortoise -- The giant Galápagos tortoise (Geochelone elephantopus) is the most distinctive animal on the entire archipelago. In fact, the name Galápagos comes from the Spanish word "galápago," which is what the early Spanish explorers and conquistadors called these tortoises, because their shells resembled riding saddles. Fifteen subspecies of giant tortoise have been recorded. Of these, four are confirmed extinct, and another, the Isla Pinta subspecies, is on the verge of extinction.

Given the geological isolation and workings of evolution, almost every major island on the archipelago has one or more distinct subspecies. The various subspecies can be divided into two general classes, based on the shapes of their shells. Generally speaking, shells are dome-shaped or saddle-backed. The domed tortoises tend to live in higher, moister environments, and their plentiful food is found close to the ground. Their shells have very little curvature above their necks. Conversely, the saddle-backed tortoises live in more desertlike, arid environments, and they often have to reach high for their favorite foods. Hence, their shells are characterized by the large open arch above their neck areas, allowing them to make these reaches. Domed-shell tortoises tend to be larger than their saddle-backed brethren, too -- though most are large by nearly any standard.

For millions of years, the Galápagos tortoise had virtually no natural predators. Eggs and hatchlings were vulnerable to certain hawks and owls, but beyond that they lived a totally unthreatened life until people arrived. Early explorers, settlers, and pirates found the tortoise to be an invaluable and easy source of food, and thousands upon thousands of tortoises were slaughtered. These same early settlers introduced non-native species, such as goats, pigs, dogs, and rats, that devastated the island's tortoise habitat, and, in some cases, the reptiles themselves. Today, several subspecies remain threatened or in danger of extinction, while many others have stable and growing populations, thanks to the efforts of conservationists, scientists, and the Charles Darwin Foundation.

On Isabela Island

Isabela is a picturesque little island with a burgeoning tourism scene. Despite its remote and undiscovered feel, the island has many attractions and activities to keep visitors busy. Snorkeling and scuba diving are excellent here, and there are a host of great hikes, mountain-biking trails, deserted beaches, and wildlife-viewing opportunities.

Some of the most popular tours and activities are hikes to the massive crater of the still-active Cerro Negro (also called Sierra Negra), and beyond to the impressive lookout at Cerro Chico; or to El Muro de Lágrimas (The Wall of Tears), a stone wall that was used as a torture mechanism for prisoners kept in a penal colony here during the mid-20th century. On a visit to the Wall of Tears, you actually have the opportunity to see Galápagos tortoises in the wild. Other options include a boat ride to Los Tintoreros, a small island where you can see sea lions, marine iguanas, and nurse sharks, in a small, man-made-but-natural-looking canal flanked by a walkway. Los Tuneles is another popular snorkel spot, with lava tunnels and arches, and abundant marine life in shallow waters. There is also a tortoise-hatching facility, or Galapaguero, with a small museum and pens with a couple dozen tortoises representing several different species. For any of these, or other tour options, ask at your hotel, or contact Papi's Tours (tel. 05/2529-392) or Tropical Adventures (tel. 05/2529-085). For scuba-diving and snorkel tours, check in with The Isabela Dive Center (tel. 05/2529-418; www.isabeladivecenter.com.ec).

Note: There is no bank or ATM on Isabela, so be sure to bring enough cash for your stay.

On Floreana Island

Floreana is the most isolated and undeveloped of the inhabited islands on the Galapágos, with just some 150 permanent residents and very little tourism infrastructure. This is a great place to come to get away from it all, or if you want to dig into the island's sordid history.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.