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November 21, 2016 0

The Galapagos tortoises are native to seven of the Galapagos Islands, a volcanic archipelago that is about 620 miles west of the mainland of Ecuador. The islands were named by Spanish explorers in the late 16th century. Because of the giant tortoises found there, they were named Insulae de los Galapagos, which means Islands of the Tortoises in Spanish. Learn about the Galapagos Islands tortoises, the most impressive creatures in the archipelago.

Galapagos giant tortoises
The name “Galapagos” comes from an old Spanish word which means “tortoise”.

History of Galapagos Tortoises

The Galapagos tortoise is thought to be an ancestral relation to tortoises from mainland South America. There is DNA evidence that the closest living relative to the Galapagos tortoise is the Chaco tortoise that is native to Argentina and Paraguay. It is believed that the tortoises floated from the mainland to the volcanic islands over 5 million years ago. They were able to survive the 620-mile ocean journey because they are buoyant, can extend their necks up for air, and can live for months without fresh water or food.

Over time, the tortoises evolved to meet the needs of their new environment. They populated the other Galapagos Islands by traveling “stepping-stone style” from one to another.

Blackberry in the Galapagos Islands
Blackberries are an invasive species in the Galapagos Islands, they are one of the most dangerous to the environment of the Islands.

Species of Galapagos Tortoises

Scientists have identified 15 different sub-species of the Galapagos tortoise, although there are only 10 species alive at this time. An 11th sub-species, now extinct, had one member nicknamed “Lonesome George” until he passed on in 2012. Of the 10 remaining species, five inhabit the largest island, Isabella, while there are six subspecies that are on separate, smaller islands. Many of the living subspecies are currently endangered or threatened species, but conservationists are working hard to increase their numbers.

Lonesome George
Lonesome George was the last of La Pinta tortoises.

Why are Galapagos Tortoises Endangered?

It is believed that when these giant tortoises were discovered in the 1600s, there were over 250,000 of them. While the lowest numbers were seen in the 1970s at about 3,000, there are currently approximately 20,000 Galapagos tortoises living in the islands. Conservation efforts have had great success with breeding programs to increase the populations.

It is believed that many of the tortoises were hunted by humans for meat and oil. Others may have died off when non-native animals such as pigs, goats, and rats were introduced to the islands. In the past 50 years, many subspecies were bred in captivity and released to their native habitats to repopulate those areas.

Learn about the Galapagos Islands Tortoises Size

Galapagos tortoises are quite large, and even their legs and feet are large and thick, resembling that of an elephant. Another important fact to note is that their front feet have five claws while those on the back have only four. Despite their size, the tortoises can pull all four of their feet and their heads inside of their shells for protection.

The actual measurements and weights of these tortoises can vary depending on individuals and subspecies. Some of the smaller tortoises live on the island of Pinzon. The largest of these smaller tortoises weighs in at about 168 pounds with a shell size of about 2 feet. Many of the tortoises on the other islands, however, are much larger. The largest recorded Galapagos tortoise weighed in at approximately 880 pounds, and its shell measured over 6 feet across.

Galapagos giant tortoise
Several conservation efforts are being made in order to preserve the giant tortoises’ population in the Islands.

The Shells of the Galapagos Tortoises

The shells, scientifically known as carapaces, are fused with the ribs and are a protective part of the tortoise’s make-up. The shells are dull brown in color and have characteristic patterns that remain the same throughout the tortoise’s life.

Two different shell types are common, depending mostly on where the tortoise lives. Some tortoises have saddleback shells, which are longer than they are wide and arch upwards at the front. When a tortoise brings its front legs and head inside of a saddleback shell, there is a gap, which denotes to scientists that these tortoises have few, if any, natural predators. Other tortoises have a domed shell that is totally concave in shape.

About the Galapagos Islands Tortoises Behaviors and Eating Habits 

An important fact about the Galapagos Islands tortoises is that as cold-blooded reptiles, they like to warm up each morning before heading out in search of food. They will often lie in the sun for several hours. In the evening, when they are ready to sleep, they often lie in a shallow pit or in the close quarters of rock caves.

Giant tortoises are herbivores, eating many plants and fruits that are native to the islands they live on and spending a good part of their days foraging for food. As for water, they get most of this from the dew in the grasses and the moisture in the vegetation they eat. They can go for six months to a year without any food or water, living on the fat stored in their bodies.

Life Cycle of Galapagos Tortoises

Mating rituals require males to dominate over other males for the right to mate with a female. The actual process of domination and mating can be somewhat aggressive. Typically, tortoises mate from February to June, but it can occur at any time.

Several months later, the females search for a dry place to build a nest and lay their eggs. They can lay up to 16 eggs per nest. The temperature will determine the gender of the hatchlings. Eggs near the surface, incubated at a slightly warmer temperature, will yield mostly females, while the slightly cooler-incubated eggs, will take longer and will produce mostly males. After digging their way out of the sealed nest, the hatchlings emerge four to eight months later, weighing less than a pound. They stay in the warmer, dryer climates for the first 10-15 years of life, not reaching sexual maturity until possibly 40 years old. As hatchlings, they face much adversity, from encounters with the Galapagos hawks to the possibility of falling into cracked earth. However, those that survive live to be over 100 years old in the wild.

Read more about the Galapagos Islands tortoises here, or be enchanted by the Galapagos Islands

Finch Bay Galapagos Hotel

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September 8, 2016 0

The Galapagos Archipelago is celebrated worldwide for its unique plant and animal species; however, the miraculous marine life that surrounds these islands is often overlooked. The processes that have so enthralled the scientific community since the arrival of the H.S. Beagle are also clearly represented in those species that live below the ocean waves, not just in those above. Around 3,000 marine species call these waters home, of which over 20% are endemic to the Galapagos marine reserve, including around 400 are fish species alone. Just sticking your head below the ocean surface, an equally fantastic and stunning world can be found. Unfortunately, studies have found that rising temperatures and acidity levels in the ocean are threatening the marine biosphere, starting first and foremost with coral reefs.

Why is the Galapagos Marine Reserve so diverse?

Snorkeling in the Galapagos Islands
A lot of the Galapagos Islands diversity is composed of its marine life.

The beauty and richness of the Galapagos Marine Reserve are foremost due to the archipelago’s location at the conjunction of at least three major ocean currents, joining warm northern waters with rich arctic waters and deep cold waters from the west. As a result, a unique array of life comes together resulting in an extraordinarily high level of endemism. Endemism is much rarer among marine life than terrestrial species, as marine species are more prone to long migrations and intermingling. The multitude of life is only strengthened by the diverse marine habitats located below the stunning turquoise waters, including vertical walls, coral reefs, rocky bottoms, sandy beaches, and mangrove forests.

 

Foreboding dangers

After decades of warnings from the scientific community, the world is beginning to suffer the initial effects of climate change. Reports demonstrate that the global temperature has increased 0.7°C since pre-industrial times, the effect of which is being felt by marine species from the equatorial tropics to the deep poles. Rising ocean levels, water temperature, and water acidity all present potentially threating situations for our oceans.

Some of the most essential organisms affected by increasing ocean temperatures are plankton and algae which, although they may seem irrelevant, are the veritable foundation of the marine food chain and are hugely important to a healthy marine environment, especially coral. If ocean temperatures rise by just one degree Celsius for as little as four weeks, coral expels the algae they contain in response to heat stress through a process known as coral bleaching. Algae are the primary food producer for coral and provide up to 90 percent of the energy corals need to reproduce and grow. Without algae, coral slowly appears to become transparent, revealing its white skeleton. If water conditions do not return to normal, coral is not able to regain the algae and will literally starve. Coral bleaching has become dangerously widespread in recent years, and the Galapagos Islands are not an exception.

Galapagos coral and its global significance

The Galapagos Islands are not typically known for their coral reefs, and indeed it was not until the 1970’s that scientists realized the Galapagos Marine Reserve contained coral; nevertheless, they play a very important role in determining the potential effects of climate change on reefs around the world. The unusual current patterns present in the archipelago and its isolation from human activity makes it the perfect ‘living laboratory’ for studying these effects. The Living Oceans Foundation has been conducting extensive research in the archipelago with the support of the University of Miami in an effort to evaluate how coral in the Galapagos is able to recover from strong El Niño events, as well as the impact that ocean acidification may have on the coral.

The future of coral

During the El Niño events of 1982-83 and 1997-98, a large part of the coral in the Galapagos died due to extremely high water temperatures. Only one reef truly recovered, which is located by the northernmost island in the Galapagos, Darwin Island. The coral reefs that survived were studied and compared to those that did not in order to understand the conditions that made coral more susceptible. Unfortunately, the results do not bode well for the future of coral reefs; however, as some coral is more thermotolerant than others, there is still hope. Furthermore, the study determined that distinct Symbiodinium species (unicellular organisms) cause certain kinds of coral to respond differently to bleaching; therefore, if a coral is able to host multiple symbiont types, it will be better equipped to cope with warming waters. One reason the northern coral survived was due to lower levels of acidity in that area (as a result of differing ocean currents), determining that reefs in the Galapagos are unable to survive if the water has a pH of 8.0 or less. Furthermore, after carrying out several lab studies, it was determined that the coral that died had weaker skeletons as a result of increased levels of phosphate in the water due to nutrient-rich upwellings; the increase in nutrients caused the coral to grow faster, forming less robust skeletons. The study thus found that those corals in highly acidic waters and exposed to higher levels of nutrients would be least resistant to the effects of climate change.

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Image Credits: Wikipedia

Finch Bay Galapagos Hotel

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