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Galapagos Islands-337 | by Tristan27
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Galapagos Islands-337

One of the amazingly colourful Marine Iguanas from Suarez Point on Espanola.


Marine Iguana

The Marine Iguana (Amblyrhynchus cristatus) is an iguana found only on the Galapagos Islands that has the ability, unique among modern lizards, to live and forage in the sea. It has spread to all the islands in the archipelago, and is sometimes called the Galapagos Marine Iguana. It mainly lives on the rocky Galapagos shore, but can also be spotted in marshes and mangrove beaches. On his visit to the islands, Charles Darwin was revolted by the animals' appearance, writing “The black Lava rocks on the beach are frequented by large (2-3 ft), disgusting clumsy Lizards. They are as black as the porous rocks over which they crawl & seek their prey from the Sea. I call them 'imps of darkness'. They assuredly well become the land they inhabit.” In fact, Amblyrhynchus cristatus is not always black; the young have a lighter coloured dorsal stripe, and some adult specimens are grey. The reason for the sombre tones is that the species must rapidly absorb heat to minimize the period of lethargy after emerging from the water. They feed almost exclusively on marine algae, expelling the excess salt from nasal glands while basking in the sun, and the coating of salt can make their faces appear white. In adult males, coloration varies with the season. Breeding-season adult males on the southern islands are the most colorful and will acquire reddish and teal-green colors, while on Santa Cruz they are brick red and black, and on Fernandina they are brick red and dull greenish. Another difference between the iguanas is size, which is different depending on the island the individual iguana inhabits. The iguanas living on the islands of Fernandina and Isabela (named for the famous rulers of Spain) are the largest found anywhere in the Galápagos. On the other end of the spectrum, the smallest iguanas are found on the island on Genovesa. Adult males are approximately 1.3 m long, females 0.6 m, males weigh up to 1.5 kg. On land, the marine iguana is rather a clumsy animal, but in the water it is a graceful swimmer, using its powerful tail to propel itself. As an exothermic animal, the marine iguana can spend only a limited time in the cold sea, where it dives for algae. However, by swimming only in the shallow waters around the island they are able to survive single dives of up to half an hour at depths of more than 15 m. After these dives, they return to their territory to bask in the sun and warm up again. When cold, the iguana is unable to move effectively, making them vulnerable to predation, so they become highly aggressive before heating up (since they are unable to run away they try to bite attackers in this state). During the breeding season, males become highly territorial. The males assemble large groups of females to mate with, and guard them against other male iguanas. However, at other times the species is only aggressive when cold. Marine iguanas have also been found to change their size to adapt to varying food conditions. During El Niño conditions when the algae that the iguanas feed on was scarce for a period of two years, some were found to decrease their length by as much as 20%. When food conditions returned to normal, the iguanas returned to their pre-famine size. It is speculated that the bones of the iguanas actually shorten as a shrinkage of connective tissue could only account for a 10% length change. Researchers theorize that land and marine iguanas evolved from a common ancestor since arriving on the islands from South America, presumably by driftwood. It is thought that the ancestral species inhabited a part of the volcanic archipelago that is now submerged. A second school of thought holds that the Marine iguana may have evolved from a now extinct family of seagoing reptiles. Its generic name, Amblyrhynchus, is a combination of two Greek words, Ambly- from Amblus meaning "blunt" and rhynchus meaning "snout". Its specific name is the Latin word cristatus meaning "crested," and refers to the low crest of spines along the animal's back. Amblyrhynchus is a monotypic genus in that Amblyrhynchus cristatus is the only species which belongs to it at this point in time. This species is completely protected under the laws of Ecuador. El Niño effects cause periodic declines in population, with high mortality, and the marine iguana is threatened by predation by exotic species. The total population size is unknown, but is, according to IUCN, at least 50,000, and estimates from the Charles Darwin Research Station are in the hundreds of thousands. The marine iguanas have not evolved to combat newer predators. Therefore, cats and dogs eat both the young iguanas and dogs will kill adults due to the iguanas' slow reflex times and tameness. Dogs are especially common around human settlements and can cause tremendous predation. Cats are also common in towns, but they also occur in numbers in remote areas where they take a toll on iguanas.


Espanola (Suarez Point)

Approximately a 10-12 hour trip from Santa Cruz, Española is the oldest and the southernmost island in the chain. The trip across open waters can be quite rough especially during August and September. Española's remote location helped make it a unique jewel with a large number of endemic creatures. Secluded from the other islands, wildlife on Española adapted to the island's environment and natural resources. The subspecies of Marine iguana from Española are the only ones that change color during breeding season. Normally, marine iguanas are black in color, a camouflage, making it difficult for predators to differentiate between the iguanas and the black lava rocks where they live. On Española adult marine iguanas are brightly colored with a reddish tint except during mating season when their color changes to more of a greenish shade. The Hood Mockingbird is also endemic to the island. These brazen birds have no fear of man and frequently land on visitors heads and shoulders searching for food. The Hood Mockingbird is slightly larger than other mockingbirds found in the Galapagos; its beak is longer and has a more curved shape. The Hood Mockingbird is the only carnivorous one of the species feeding on a variety of insects, turtle hatchlings and sea lion placentas. Wildlife is the highlight of Española and the star of the show is the waved albatross. The island's steep cliffs serve as the perfect runways for these large birds which take off for their ocean feeding grounds near the mainland of Ecuador and Peru abandoning the island between January and March. Known as endemic to the island, Española is the waved albatross's only nesting place. Each April the males return to Española followed shortly thereafter by the females. Mating for life, their ritual begins with the male's annual dance to re-attract his mate. The performance can take up to 5 days consisting of a series of strutting, honking, and beak fencing. Once the pair is reacquainted they produce a single egg and share the responsibility of incubation. The colony remains based on Española until December when the chick is fully grown. By January most of the colony leaves the island to fish along the Humboldt Current. Young albatross do not return to Española until their 4th or 5th year when they return to seek a mate. Geographically Española is a classic example of a shield volcano, created from a single caldera in the center of the island. Over the years as the island has moved further away from the hot spot, the volcano became extinct and erosion began to occur. Española's two visitor sites offer an exceptional island visit. Punta Suarez is one of the highlights of the Galapagos Islands. The variety and quantity of wildlife assures a memorable visit. Visitors find migrant, resident, and endemic wildlife including brightly colored Marine Iguanas, Española Lava Lizards, Hood Mockingbirds, Swallow Tailed Gulls, Blue Footed and Masked Boobies, Galapagos Hawks, a selection of Finch, and the Waved Albatross.Found on the western tip of Española, Punta Suarez offers great wildlife such as sea lions, sea birds and the largest marine iguanas of Galapagos. This is one of the best sites in the Galapagos. The amount of wildlife is overwhelming. Along the beach there are many sea lions and large, colorful lava lizards and marine iguanas. As you follow the trail to the cliff's edge masked boobies can be found nesting among the rock formations. After a short walk down to a beach and back up the other side blue-footed boobies are seen nesting just off the trail. The Galapagos Dove and very friendly Hood Mockingbird are commonly found in this area. The nearby bushes are frequently home to the large-cactus finch, warbler finch, small-ground finch and large-billed flycatcher. Continuing down the trail you come to the only place where waved albatross nest in the islands. Some 12,000 pairs nest on Española each year. The feeling is very dramatic and it seems like a desolate wilderness as the waves crash on the jagged cliffs below and the blowhole shoots water 50-70 feet/15-30 meters into the air. The sky above is full of sea birds including red-billed tropicbirds, American Oystercatchers, swallow-tailed gulls, and Audubon's Shearwaters.


Galapagos Islands

The Galápagos Islands (official name: Archipiélago de Colón; other Spanish names: Islas de Colón or Islas Galápagos) are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, some 900 km west of Ecuador. It is a UNESCO World Heritage site: wildlife is its most notable feature. Because of the only very recent arrival of man the majority of the wildlife has no fear of humans and will allow visitors to walk right up them, often having to step over Iguanas or Sea Lions.The Galápagos islands and its surrounding waters are part of a province, a national park, and a biological marine reserve. The principal language on the islands is Spanish. The islands have a population of around 40,000, which is a 40-fold expansion in 50 years. The islands are geologically young and famed for their vast number of endemic species, which were studied by Charles Darwin during the voyage of the Beagle. His observations and collections contributed to the inception of Darwin's theory of evolution by natural selection.

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Taken on April 21, 2009