From the Wild File: Galapagos Giant Tortoise
The Galapagos giant tortoise (Chelonoidis nigra) is one of the most famous animals of the Islands, with the archipelago itself being named after them (Galapágo is an old Spanish word for tortoise). Take a closer look at this iconic creature.
Galapagos tortoises are herbivores that eat prickly pear cactus and fruits, as well as flowers, leaves, and grasses. In captivity the tortoises will eat carrots, bamboo stalks, various greens, seasonal fruits and vegetables, hibiscus leaves and flowers, and other foods that are high in fiber. They have very slow digestive systems; it can take their bodies up to three weeks to fully process a meal. Tortoises don’t have teeth, so they use the bony outer edges of the mouth to bite off and mash food. Once in the mouth, food is quickly swallowed.
LIFE SPAN & SIZE
They can live more than 100 years. One captive individual survived 170 or so years. These gentle giants are the largest living tortoise in the world. Males may weigh more than 500 pounds, and females average about 250 pounds.
Breeding usually occurs between January and June. Between two to 20 eggs are laid, which are almost the size of a tennis ball. After covering the nest, the eggs are left to incubate for four to eight months by the female. The temperature of the nest determines how long the incubation will take as well as the sex of the offspring. Lower temperatures tend to produce more males. The young tortoises usually hatch between November and April.
Although they are massive animals, their shells are not solid. Instead, they are made up of honeycomb structures that enclose small air chambers. This makes it possible for the tortoise to carry the weight of the shell without much difficulty. The shell encompasses the animal’s ribs. The lungs are located on the top of the tortoise’s body, under the top dome of the shell. They have large, strong legs and are capable of climbing over substantially sized rocks.
A total of 12 species live among the islands. Six are listed as "Critically Endangered," three as "Endangered," and three as "Vulnerable" on the IUCN Red List. Giant tortoises show large variation in size and shape, but all species can be classed into two main shell types: domed and saddle-backed. Islands with humid climate have larger tortoises with domed shells and shorter necks; dry climates lead to somewhat smaller tortoises with saddle-backed shells and long necks. The shell color is a dark greyish-brown.
WHO'S IN CHARGE?
Dominance is decided by who can stretch their neck and head the highest. Comparing heights decides who gets dibs on the best resources. Competing males will stand tall, necks stretched and facing each other with mouths agape. The highest head usually always wins.
The Galapagos giant tortoise spends an average of 16 hours per day resting. They enjoy bathing and can survive for up to a year without ingesting water or food.
The average speed of a walking tortoise is .18 miles per hour. At its fastest, a tortoise can move at about .5 miles per hour. This is pretty impressive considering that a female tortoise will travel about 4 miles to lay her eggs.
Small birds, such as Galapagos finches, can often be seen sitting on the backs of giant tortoises. The birds and tortoises have formed a symbiotic relationship in which the birds peck the ticks out from the folds of the tortoises’ skin.
Like other reptiles, Galapagos tortoises are cold-blooded animals. They spend much of their day soaking up the sun to warm themselves. When the sun goes down and the temperature cools, tortoises sleep partially submerged in mud, water or brush to keep warm.
Voyage to the Galapagos Islands with us, and encounter these giant tortoises year-round with several departure options available. Hike, snorkel, and swim on this memorable small-group nature adventure!