Galápagos Islands flora and fauna

While the land environment of Galapagos appears harsh, characterised by parched, rocky desert-like terrain, the islands support several species of land animals and birds. About a quarter of all plant species and nearly all of the reptiles found here are endemic, species that are found nowhere else and have adapted to the harsh environment of the Galapagos Islands.

This environment has, however, limited species diversity while creating a delicate balance between species. Some are completely dependent on others, both plant and animal. While there is some speculation that at one time (millions of years ago) a land bridge from Costa Rica to the Galapagos may have existed, the islands probably were never connected to the mainland. Thus the species that exist here could only arrive through flight or by floating to the islands on large, floating areas of vegetation washed down by South American rivers. Seeds and insects were perhaps brought from the continent by high winds; birds also could have carried seeds with them to the islands. The lack of large mammals or amphibians prior to the arrival of man is explained by the problem of arrival—they simply were not suited for the journey.

The Galapagos Islands have four primary ecosystems, formed by climate patterns and differences in elevation. The lowlands, generally arid areas with forests of cactus, comprise the first ecosystem. Moving upwards in elevation, the next system is subtropical forests, and the third is more humid, dense forests. The fourth consists of primarily ferns and grasses at the highest elevations. Only the largest islands, such as Isabella, contain all four systems.

Marine Environment

The Galapagos Islands are situated at the confluence of several ocean currents, which not only helps account for the mild climate in the islands, but also its remarkable diversity of beautiful marine life. The cold, salty Humboldt Current runs northward along the South American coast from the Antarctic, turning westward near the equator bringing cool waters to the islands. The warm, less saline Panama current, runs southward along the coast of Central America turning westward near the equator. The cool Southern Equatorial Current runs westward, continuing with the energy of the Humboldt. Deep below the ocean surface, the Equatorial Countercurrent (also known as the Cromwell) runs from the west towards the islands, and is diverted upwards by the western islands, bringing cool, nutrient rich waters from the deep ocean to the island region.

The variation in the underwater landscape, including underwater volcanoes rising nearly to the surface, adds to the diversity found here. Over 2900 marine species have been identified in the area, and about 18% of these are found nowhere else.

Endemic Species

Many species on the Galapagos are found nowhere else. Having developed and lived in isolation from humans, most species found there are nearly fearless of humans, and can be approached at close range. Below are some of the species unique to the Galapagos islands:

Galapagos Mammals

Galapagos Sea Lions

One of the most playful and entertaining animals of the Galapagos, they often will swim with visitors at the beaches of Galapagos. Found throughout the Galapagos islands, they have also formed a colony on Isla de la Plata just off the coast of Ecuador. They feed primarily on sardines, and can travel several kilometers off the coast to search for food. Their major predators are sharks and killer whales; sea lions often carry scars from battles at sea.

The social and inquisitive nature of the Galapagos sea lions makes them highly vulnerable to human activity. They willingly approach areas inhabited by humans, bringing them into contact with human waste, fishing nets and hooks which can do serious harm to the animals.

Galapagos Fur Seal

Much smaller than the Galapagos Sea lion, they have a thicker fur coat revealing their ancestry to the colder southern coasts of Peru and Chile. They were heavily hunted during the 19th century, when demand in Europe and the US for their pelts was high, and nearly brought to extinction. Today, they have recovered, with a total population of about 30 to 40 thousand on the islands of Pinta, Marchena, Santiago, Isabela and Fernandina.