'Lonesome George': The World's Rarest Animal

I've always been fascinated by extinct (and extinct-in-the-wild) animals. Sure, the circumstances of their extinction, and attempts to imagine a world where they existed (try, for example, to conjure up an image of flocks of passenger pigeons which could darken the sky for days, as described by Audubon) are incredibly interesting, but beyond that I've always wondered about the last single representative of those dying species.

That brings me to the subject of this article: the animal which is currently labeled as the rarest in the world. There are not a few hundred of this species left, nor a few dozen. No, there is only one known Pinta Island tortoise (Geochelone elephantopus abingdoni) in existence, a 90ish year old male called Lonesome George.

Who is Lonesome George?

By the year 1962, when the Charles Darwin Research Station was opened on the island of Santa Cruz, the Pinta Island tortoise had been declared extinct, along with four other species of giant tortoise.

Imagine the surprise, then, of the researcher who, while studying Pinta Island's snails in December of 1971, saw a single tortoise on the island. The researcher immediately contacted Galapagos authorities. A search began for this solitary reptile, and in 1972 a Pinta Island tortoise was brought to Santa Cruz Island's research station.

The keepers named the male (who is currently thought to be around 90 years old, which seems ancient until you realize that giant tortoises can live in excess of 150 years) "Lonesome George."

Pinta Island's Ecology

So how did Lonesome George end up as the last known Pinta Island tortoise?

To understand that, we'll have to take a look at the history and the ecology of Pinta Island itself. Pinta Island is the northernmost island of the Galápagos Islands. This tiny island, which has a land area of around 35 square miles, used to have a thriving population of giant tortoises, gulls, iguanas and other indigenous animals.

The downfall of Pinta Island's ecology can be traced to the introduction of one species in 1958: goats. When goats were introduced by fishermen to the tiny island, they immediately began to wreak havoc. Not only did these invasive animals destroy much of Pinta Island's vegetation, they also introduced disease (which many of the native species had no immunity to) and destroyed habitat. The eradication of feral goats on all islands of the Galápagos has become a top priority in the last 30 years.

Attempts to breed Lonesome George

You may be wondering how it is possible to attempt to breed a single animal. Before you begin imagining some futuristic mad-scientists-like scenario, let me explain how scientists have attempted to breed Lonesome George:

The Pinta Island tortoise is one of several subspecies of Galápagos tortoises. This means that all of these subspecies of giant tortoise, though dissimilar enough to be considered separate subspecies, still share many genetic characteristics. If two subspecies which are very similar biologically mate, it may be possible to produce offspring that retain the genotype for one species. There is no hope of creating a purebred Pinta Island tortoise through this method, but much of the genetic material, if successful, could survive.

Therefore, researchers at the Charles Darwin Research Station have kept Lonesome George in an enclosure with two females of the subspecies Geochelone nigra becki in the hopes that mating could occur. Much to the surprise of scientists, clutches of eggs were laid by one of the female tortoises in 2008 and 2009. These eggs, however, proved to be unviable and would not provide the offspring that would carry on the genetic legacy of the Pinta Island tortoise.

A reward of $10,000 still stands for anyone who can find a female Pinta Island tortoise.

Is Lonesome George really alone?

Though Lonesome George is considered to be the last of the Pinta Island tortoises, there may be hope that he is not entirely alone. As recent as 2007 genetic analysis has shown that some giant tortoises on the island of Isabela have a genetic makeup very similar to George's. This indicates to scientists that there may be Pinta Island tortoises interbreeding with that island's own subspecies. How many tortoises is the real question. Based on the genetic profiles of the potential mixed-breed Isabela tortoises, there likely aren't very many. Of course, this remains mostly speculation, as no Pinta Island tortoises have been verified.

Yet another possible Pinta Island tortoise, named Tony, resides in the Prague Zoo. This male tortoise, which is estimated to be about 50 years old, has an extremely similar shell pattern to Lonesome George's and museum specimens. DNA testing still must be done to determine if Tony is the second known Pinta Island tortoise.

Even with these potential purebred Pinta Island tortoises, the outlook for the species is decidedly bleak.

Sources:

Galápagos ConservancySkeptic Magazine: Is Lonesome George Really Lonesome?Tortoise TrustRochester Institute of Technology: Galápagos Giant Tortoises