The Galapagos Islands include over 50 islands and islets within the recently created 138,000 square kilometer Galapagos Marine Reserve, with a total land area of about 7,880 square kilometers. Within the island chain are 13 islands; the largest of which are Isabella, Fernandina, Santa Cruz, San Cristobal, Floreana, Santiago and Fernandina. Several smaller islets, along with countless rock formations complete the island chain. Most islands have a dry and inhospitable environment, limiting the diversity of land species, but several species unique to the islands have evolved to survive in the harsh environment. However, the location of the islands at the confluence of the cold Humboldt current from the south and warmer currents from the west and north has helped create an amazingly diverse and beautiful marine ecosystem. A number of marine bird species thrive on the islands as well. Without a long history of human contact, most wildlife on the Galapagos can be easily approached.
Each island in the Galapagos offers something a bit different. Still among the most volcanically active areas on earth, the islands originally formed about 6 million years ago from underwater volcanic activity. The oldest of the islands are extinct volcanoes, last erupting millions of years ago, while some of the islands are still changing form with continuing volcanic activity. Thus the landscapes of each island are a bit different, and support different kinds of life. Marine life forms are equally varied from island to island, including a variety of birds, sea lions, iguanas, sharks, rays, penguins, and a surprising variety of other fishes and marine life.
Kept relatively cool by the ocean currents, the Galapagos Islands have a pleasant climate year round, but temperatures can still reach 30 degrees C or more. The warmest months are from December to June, months where afternoon rainfall is also common. July through November are generally cooler and drier months, but light drizzle can fall during this period. The water temperature varies as well, from about 18 °C (66 °F) in August to 24 °C (76 °F) in February, March and April.