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Galapagos Islands-691 | by Tristan27
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Galapagos Islands-691

Galapagos Sea Lions on the beach on Isabella

 

Galapagos Sea Lion

The Galápagos Sea Lion (Zalophus wollebaeki) breeds on the Galápagos Islands and – in smaller numbers – on Isla de la Plata (to Ecuador). Being fairly social, and one of the most numerous species in the Galápagos archipelago, they are often spotted sun-bathing on sandy shores or rock groups or gliding gracefully through the surf. Their loud “bark”, playful nature, and graceful agility in water make them the “welcoming party” of the islands. They are lightly smaller than their Californian relatives, Galápagos Sea Lions range from 150 to 250 cm in length and weigh between 50 to 400 kg, with the males much larger than females. Adult males also tend to have a thicker, more robust neck, chest, and shoulders in comparison to their slender abdomen. Females are somewhat opposite males with a longer, more slender neck and thick torso. Once sexually mature, a male’s sagittal crest enlarges, forming a small, characteristic bump-like projection on their forehead. Galápagos Sea Lions, compared to California sea lions, have a slightly smaller sagittal crest and a shorter muzzle. Adult females and juveniles lack this physical characteristic altogether with a nearly flat head and little or no forehead. Both male and female sea lions have a pointy, whiskered nose and somewhat long, narrow muzzle. The young pups are almost dog-like in profile. Another characteristic that defines the sea lion are their external ear-like pinnae flaps which distinguish them from their close relative in which they are often confused with, the seal. The fore-flippers have a short fur extending from the wrist to the middle of the dorsal fin surface, but other than that, the flippers are covered in black, leathery skin. Although somewhat clumsy on land with their flippers, sea lions are amazingly agile in water. With their streamline bodies and flipper-like feet, they easily propel themselves through crashing surf and dangerously sharp coastal rocks. They also have the ability to control their flippers independently and thus change directions with ease and have more control over their body on land. When wet, sea lions are a shade of dark brown, but once dry, their color varies greatly. The females tend to be a lighter shade than the males and the pups a chestnut brown. Born with a longer, brownish-black lanugo, a pup's coat gradually fades to brown within the first five months of life. At this time, they undergo their first molt resulting in their adult coat. Feeding mostly on sardines, Galápagos Sea Lions sometimes travel ten to fifteen kilometers from the coast over the span of days to hunt for their prey. This is when they come into contact with their biggest predators: sharks and killer whales. Injuries and scars from attacks are often visible. Galápagos Sea Lions are especially vulnerable to human activity. Their inquisitive and social nature makes them more likely to approach areas inhabited by humans, and thus come into contact with human waste, fishing nets, and hooks. They occupy many different shoreline types from steep, rocky cliff sides to low-lying sandy beaches. To avoid overheating during the day, sea lions will take refuge from the sun under vegetation, rocks, and cliffs, and wade into tidal pools. Not only are sea lions social, they are also quite vocal. Adult male Galápagos Sea Lions often bark in long, repeated sequences that are loud and distinctive. Females and juveniles do not produce this repetitive bark, but both sexes and the younger pups will growl. From birth, a mother sea lion recognizes her pup’s distinct bark and can pin point it from a crowd of thirty or more barking sea lions. On land, sea lions form colonies at their hauling-out areas. Adult males known as Bulls are the head of the Colony, growing up to 7 ft (2 m) long and weighing up to 800 lb (363 kg). As males grow larger, they fight to win dominance of a harem of between 5 and 25 cows and the surrounding territory. Swimming from border to border of his colony, the dominant bull jealously defends his coastline against all other adult males. While patrolling his area, he frequently rears his head out of the water and barks, as an indication of his territorial ownership. The average dominant bull holds his territory for only a few months, until he is challenged by another male. On land, these fights start by stretching out the neck and barking in attempt to test each other’s bravery. If this isn’t enough to scare the opponent off, they begin pushing each other and biting around the neck area. If males weren’t equipped with a thick, muscular neck, their vital organs would be easily damaged during these fights. Blood, is often drawn, however, and many male sea lions have battle scars due to these territorial competitions. Losers are dramatically chased far from their territory by the new dominant bull with much splashing. Because there is only one male in each harem, there is always a surplus of “bachelor” male sea lions. They usually congregate fairly peaceably on less favorable areas of the coastline in “bachelor colonies.”. Because the dominant male of the harem cannot feed while defending his colony, he eventually becomes too tired and weak, and is overpowered by the well-nourished, fresh bull. Breeding takes place from May all the way through to January. Because of this prolonged breeding season and the extensive care required by the pups from their mother, there are dependent pups in the colonies year round. Each cow in the harem has a single pup born a year after conception. After about a week of continuous attention from birth, the female returns to the ocean and begins to forage, and just a week after that, the pup will follow her and begin to develop its swimming skills. When the pup is two to three weeks old the cow will mate again. The mothers will take the young pups with them into the water while nursing until around the 11th month when the pups are weaned from their mother’s milk and become dependent on their own hunting skills. The pups have a strong bond with their mother. The cow will nurture a pup for up to three years. In that time the cow and the pup will recognize each other's bark from the rest of the colony. Within the colony sea lion pups live together in a rookery. Pups can be seen together napping, playing, and feeding. It is not uncommon to see one cow 'baby-sitting' a group of pups while the other cows go off to feed.

 

Isabella

Shaped like a sea horse, Isabela is the largest of the the islands in the Galapagos, more than 4 times larger than Santa Cruz the next largest. Isabela is 80 miles (100 km) in length and though it is remarkably beautiful it is not one of the most visited islands in the chain. Its visitor sites are far apart making them accessible only to faster boats or those with longer itineraries. One of the youngest islands, Isabela is located on the western edge of the archipelago near the Galapagos hot spot. At approximately 1 million years old, the island was formed by the merger of 6 shield volcanoes - Alcedo, Cerro Azul, Darwin, Ecuador, Sierra Negra and Wolf. Five of the six volcanoes are still active (the exception is Ecuador) making it one of the most volcanically active places on earth. Visitors cruising past Elizabeth Bay on the west coast can see evidence of this activity in the fumaroles rising from Volcan Chico on Sierra Negra. Two of Isabela's volcanoes lie directly on the equator - Ecuador and Volcan Wolf. Volcan Wolf is the youngest of Isabela's volcanoes and at 5,600ft (1707 m) the highest point in the Galapagos. Isabela is known for its geology, providing visitors with excellent examples of the geologic occurrences that have created the Galapagos Islands including uplifts at Urbina Bay and the Bolivar Channel, Tuft cones at Tagus Cove, and Pulmace on Alcedo. Isabela is also interesting for its flora and fauna. The young island does not follow the vegetation zones of the other islands. The relatively new lava fields and surrounding soils have not developed the sufficient nutrients required to support the varied life zones found on other islands. Another obvious difference occurs on Volcan Wolf and Cerro Azul, these volcanoes loft above the cloud cover and are arid on top. Isabela's rich animal, bird, and marine life is beyond compare. Isabela is home to more wild tortoises than all the other islands. Isabela's large size and notable topography created barriers for the slow moving tortoises; apparently the creatures were unable to cross lava flows and other obstacles, causing several different sub-species of tortoise to develop. Today tortoises roam free in the calderas of Alcedo, Wolf, Cerro Azul, Darwin and Sierra Negra. Alcedo Tortoises spend most of their life wallowing in the mud at the volcano crater. The mud offers moisture, insulation and protects their exposed flesh from mosquitoes, ticks and other insects. The giant tortoises have a mediocre heat control system requiring them to seek the coolness of the mud during the heat of the day and the extra insulation during the cool of the night. On the west coast of Isabela the nutrient rich Cromwell Current upwelling creating a feeding ground for fish, whales, dolphin and birds. These waters have long been known as the best place to see whales in the Galapagos. Some 16 species of whales have been identified in the area including humpbacks, sperms, sei, minkes and orcas. During the 19th century whalers hunted in these waters until the giant creatures were near extinction. The steep cliffs of Tagus Cove bare the names of many of the whaling ships and whalers which hunted in these waters. Birders will be delighted with the offerings of Isabela. Galapagos Penguins and flightless cormorants also feed from the Cromwell Current upwelling. These endemic birds nest along the coast of Isabela and neighboring Fernandina. The mangrove finch, Galapagos Hawk, brown pelican, pink flamingo and blue heron are among the birds who make their home on Isabela. A colorful part to any tour located on the western shore of Isabela, Punta Moreno is often the first or last stopping point on the island (depending on the direction the boat is heading). Punta Moreno is a place where the forces of the Galapagos have joined to create a work of art. The tour starts with a panga ride along the beautiful rocky shores where Galapagos penguins and shore birds are frequently seen. After a dry landing the path traverses through jagged black lava rock. As the swirling black lava flow gave way to form craters, crystal tide pools formed-some surrounded by mangroves. This is a magnet for small blue lagoons, pink flamingos, blue herons, and Bahama pintail ducks. Brown pelican can be seen nesting in the green leaves of the mangroves. You can walk to the edge of the lava to look straight down on these pools including the occasional green sea turtle, white-tipped shark and puffer fish. This idyllic setting has suffered from the presence of introduced species. Feral dogs in the area are known to attack sea Lions and marine iguanas.

 

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 23, 2009