Lonesome George, the "loneliest animal on the planet," died on June 24, 2012.

Lonesome George was the only documented Pinta Island tortoise (Chelonoidis nigra abigdoni). He was about 100 years old, and had been living in captivity at the Charles Darwin Research Station on the Galapagos Islands since 1972.

C.n. abigdoni is one of eight species of Galapagos tortoises. Ancestors of Galapagos tortoises reached the Galapagos Islands from mainland South America about 5 million years ago, soon after the islands formed.

The tortoises most likely rode the powerful Humboldt Current, which flows northwest from the coast of what is now Chile. These tortoises did not drown on the 1,000-kilometer (620-mile) journey for three reasons: they are buoyant, or float easily; they have extremely long necks, able to stretch several centimeters above the ocean surface; and they can go very long periods of time without food or freshwater.

Galapagos tortoises are the only tortoises with distinct shell shapes. Lonesome George's shell was a "saddleback," meaning it is slightly dipped near the front, making it look like a saddle. Other Galapagos tortoises have a dome-shaped shell. Still others have characteristics of both saddlebacks and domes, with overall flatter shells. These are known as "tabletop" shells.

Saddleback tortoises like Lonesome George are slightly smaller than their dome-shelled relatives, and have longer necks. Saddlebacks are native to the Galapagos' drier islands, where less vegetation grows close to the ground. Scientists speculate that natural selection favored long-necked saddlebacks, who would better stretch their necks to reach food, such as the fruit of the prickly-pear cactus.

In the mid-20th century, introduced species (mostly goats) out-competed native species like Lonesome George for food on the Galapagos Islands. Today, all eight Galapagos tortoise species are classified as vulnerable or endangered. Lonesome George, however, was the only Galapagos tortoise extinct in the wild. Today, the Pinta Island tortoise is entirely extinct.

  • Galapagos tortoises are the largest tortoises in the world. They weigh more than 150 kilograms (330 pounds). Lonesome George weighs about 88 kilograms (194 pounds).
  • Galapagos tortoises do not reach their full size until they are about 40 years old. The oldest Galapagos tortoise was Harriet, who lived at the Australia Zoo until her death in 2006. Harriet was about 175 years old when she died.
  • Galapagos tortoises eat about 2 kilograms (4.3 pounds) of leaves, grasses, and fruit every day.
  • Galapagos tortoises would not win many races. They travel about .3 kilometers per hour (.2 miles per hour).
  • Lonesome George was named after American actor George Gobel, who had a TV comedy series in the 1950s.
ancestor
Noun

organism from whom one is descended.

buoyant
Adjective

capable of floating.

extinct in the wild
Noun

highest level of conservation of a living species, when the only living members of that species are protected in captivity such as zoos or aquariums.

Noun

environment where an organism lives throughout the year or for shorter periods of time.

Humboldt Current
Noun

cold current that flows along the western coast of South America.

introduced species
Noun

a species that does not naturally occur in an area. Also called alien, exotic, or non-native species.

Lonesome George
Noun

last surviving Pinta Island tortoise.

natural selection
Noun

process by which organisms that are better -adapted to their environments produce more offspring to transmit their genetic characteristics.

tortoise
Noun

land-based turtle, usually with a tall, rounded shell.

vegetation
Noun

all the plant life of a specific place.