Galapagos Tortoises
The most recognized symbol of the Galapagos is the Tortoise. The
islands common name is Spanish for saddle; referring to the shape of the Galapagos
Tortoise Shell. With weights over 500 lbs (250 kg) and shells measuring 59 inches
(150 cm) Galapagos Tortoises are among the largest on earth. These land-based
turtles are slow moving and known for their long life span of more than 150 years.
The Tortoise played an important role in the Theory of Evolution. When Charles
Darwin visited the Galapagos Islands, the vice-governor of the Islands told him that he
could identify what island the tortoise was from simply by looking at him.
The inhabitants...state that they can distinguish the tortoise from
different islands; and that they differ not only in size, but in other characters.
Captain Porter has described those from Charles and from the nearest island to it,
namely Hood Island, as having their shells in front thick and turned up like a Spanish
saddle, whilst the tortoises from James Island are rounder, blacker, and have a better
taste when cooked.---Charles Darwin 1845
Naturalists believe Tortoises arrived in the islands clinging to a piece
of driftwood from a river mouth along the Pacific Coast. A relatively large
tortoise, related to the Galapagos Tortoise lives on the South American mainland.
The tortoises arrived in San Cristobal then spread throughout the archipelago.
Those
on individual islands or in isolated parts of the larger islands developed into its own
sub-species.
The Galapagos was once home to 15 sub-species of which 11
sub-species still exists. The smallest tortoises like those on Espaņola and Pinta have
"Saddle Backs'. While the largest of the tortoises, those on Santa Cruz and
from the Alcedo Volcano on Isabela have "Dome Backs". In this isolated
habitat these giant tortoises fill the niche occupied by larger
vegetarian mammals in continental regions.
They eat grass and cactus fruit,
flowers and stems. Soon after the rainy season the tortoises descend the mountain
slopes to feed on the grass covered flats. After that grass withers during the dry
season they climb the mountain to feed on grasses of the moist meadows.
Tortoises & Man
When man arrived in the Galapagos Tortoises numbered in the 100,000's.
For millennia these animals had gone unhampered by predators. Ideally suited
for rugged life in the Galapagos, tortoises are able to survive with little food and water
during times of drought.
As the buccaneers, whalers and fisherman arrived in the islands they
hunted tortoises as a source of meat. These same men brought pigs, goats, horses and cows
whose existence in the islands threatened young tortoises. They ate the little
vegetation that existed in the island and their hooves crushed tortoise eggs and the soft
shells of young tortoises.
When the Galapagos National
Park Service and Charles Darwin
Research Station were established in 1969 all 11 remaining species of
tortoises were endangered. One of their top priorities was stabilize the environment
for the tortoises. This required eradicating the introduced species, encouragement
of breeding and rearing of the young.
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Tortoise Rearing Center
The Charles Darwin Research Station established a tortoise-
rearing project. They have collected tortoise eggs from islands where the species has
become endangered from the introduced species. The eggs are brought to the Darwin
Station where they are incubated and hatched. The young tortoises are raised until
their shells become strong and they can withstand the threat of the introduced
predators.
This project, which began in the 1970's has been a success. Of the 11
species that were once endangered 10 species have been brought up to guarded levels. The
most noted success story is that of the Espaņola Tortoises. When the project began
the Hood Tortoise population consisted of 2 males and 11 females. These tortoises
were brought to the Darwin Station. Miraculously a third male was discovered at the
San Diego Zoo and brought to the Darwin Station to join the others in a captive breeding
program. These 13 tortoises are the parents of over 300 young tortoises now
roam free on Espaņola.
Lonesome George
In the days of buccaneers and pirates Isla Pinta was a popular stop. The island
located in the north of the archipelago was once home to thousands of tortoises.
These sea-faring men cherished the tortoises as a valuable source of meat. Tortoises
could remain alive in a ship hold for up to a year at sea with little food or other
necessities. The sailors would gather as many of the tortoises as the ship could
hold.
First the female tortoises were collected, their smaller size made them easier to
handle and store. They were also easier to collect, especially during egg laying
season, when the females would be on the beach to lay their eggs. As the female
population grew thin, the males too were collected. Over the years the tortoise
population on Pinta diminished.
By 1906 when the California Academy of Sciences visited Pinta for a scientific research
project they discovered the tortoise population had diminished to a mere 3 male
tortoises. The scientists collected the tortoises, and thought the island to be
barren of the native tortoise.
Years passed and during the 1950's fishermen working the nearby waters wanted to use
the islands to restock their meat supply while at sea. Since tortoises were no
longer available they needed another readily available source of food. They released feral
goats, which quickly multiplied and took over the island devouring the little island
vegetation that existed. Over the next few decades the goats flourished and
multiplied.
In 1971 when the National Park Service arrived at Pinta the goats had come to dominate
the island. The Park Service made the decision to attempt to restore the natural
balance to Pinta by eradicating the goats. While the park service didn't find and
eradicate all the goats they did find the unthinkable one remaining Pinta Tortoise.
He was named "Lonesome George", lonesome because he is the last of his
subspecies.
The Park Service moved 'George' to the Darwin Station where they have made every effort
to encourage him to breed with female tortoises from Wolf Volcano on Isabela (Wolf
Tortoises were found to be the closest morphologically to the Pinta Tortoises). Yet
over the past nearly 30 years of trying, no new tortoises have been born.
The Galapagos National Park Service and Charles Darwin Foundation are
working together to raise money, in order to finish eradicating the goats on Pinta and to
search the island to see if a mate might possibly exist. We hope that a mate can be
found and the Pinta Tortoises may continue.
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