Ending and Extinction. For Now? Forever?

Lonesome George. Image Source: Reuters via Guardian.

The giant Pinta (Abingdon) Island tortoise (Geochelone nigra abingdoni), Lonesome George, died at the Tortoise Centre on Santa Cruz island in the Galapagos on 24 June 2012 at over 100 years of age. He was the last known member of a subspecies of the Galapagos giant tortoise.

The subspecies are mainly named for the locations where they evolved, or the zoologists who identified them. The Galapagos islands gained fame for their unique wildlife when Charles Darwin (1809-1882) visited them in 1835. His observations there formed the bases for his 1859 work on evolutionary biology, On the Origin of Species, which you can read here or here. A glance at the Galapagos tortoise subspecies list tells how incredibly varied the creatures on these islands are. These are closely related animals, but they cannot necessarily interbreed successfully; several of the subspecies are extinct or endangered:

1. the Pinta (Abingdon) island tortoise
2. the Wolf volcano tortoise
3. the Cristóbal (Chatham) island tortoise
4. Charles Darwin's James island tortoise
5. the Pinzón (Duncan) island tortoise
6. Albert Günther's Sierra Negra volcano tortoise
7. the Española (Hood) island tortoise
8. the smaller Volcano Darwin tortoise
9. the Charles island black tortoise
10. the Santa Cruz (Indefatigable) island tortoise
11. John Van Denburgh's Volcano Alcedo tortoise
12. the Iguana Cove tortoise
13. Fantastica Fernandina (Narborough) island tortoise (disputed)
14. Santa Fe island tortoise (disputed)
15. Rábida island tortoise (disputed)  

In 1971, Lonesome George was spotted on Pinta island by malacologist József Vágvölgyi; he was then tracked down and captured in 1972 and moved to the Charles Darwin Research Station on Santa Cruz. His keeper, Fausto Llerena, was part of that 1972 expedition and cared for George until the reptile's death yesterday. Having spent so much time with Lonesome George, Llerena reflected on the animal's personality:

I like to take care of George because he is friendlier than the other tortoises. He is always attentive at my arrival and approaches me and lifts his head to greet me. We understand each other very well, although we do not use any words. ... [He is f]riendly and attentive with me, he is jealous of his space and food though, with the other tortoises that share the corral! Every time we carry out some work in the corral, he is always next to me.

Lonesome George was known as an 'ending' - the last of his kind. Once an ending dies, the species becomes extinct.

Workers remove Lonesome George's body from the Tortoise compound. Image Source: Reuters via Guardian.

Giant tortoises are endanged and extinct due to sailors' hunting practices and the introduction of goats and pigs to the islands, which ate the vegetation in previous centuries. Great efforts have been made to save their species and subspecies over the past generation.

Without a female of his subspecies available, conservationists from Ecuador's Galapagos National Park have attempted to mate Lonesome George since 1993 with a close subspecies, the Española (Hood) island tortoise. That latter subspecies was saved from extinction. The eggs the female tortoises produced from these matings were unviable.

There are two possible Pinta island tortoises remaining, although researchers are still working to confirm that they are in fact pure members of the subspecies. They are could be hybrids. One tortoise, a male, might live on a neighbouring Galapagos island, Isabela, at the foot of Wolf Volcano (his existence is hypothesized because a Pinta island hybrid was found there in 2007, leading to the search for the purebred Pinta parent). The other possible Pinta (Abingdon) tortoise, identified by the shape of his shell, is Tony (Antonio); he lives in Prague Zoo. You can see a picture of him here. A purebred species can sometimes be revived through careful breeding of hybrid descendants.

Could cloning some day recover lost species? Not yet. Conservationists considered cloning George:

Scientist Edward Lewis has made DNA scans of tortoises all over the world without finding a match. George's diet is being investigated to ensure there is no deficiency that could be causing his failure to reproduce. We have considered the theoretical possibility of cloning lonesome George, manipulating the gender of the clone, and trying to produce a female. This is theoretically possible, but practically very difficult, and the technology for cloning of tortoises has not yet been developed. Before we attempt cloning of Lonesome George, we feel we must exhaust all other possibilities first.

Who can say if the future holds such possibilities. A cloning program may one day be part of species conservation.

A Lonesome George toy from the 'Love George' fundraising appeal from Valentine's Day, 2012. Image Source: Galapagos Conservation Trust.