Lonesome George, a giant tortoise who died this past summer, was thought to be the last of his species. DNA evidence now, however, suggests more of his kind might still exist.
The species, Chelonoidis abingdoni, native to Pinta
Island in the Galapagos Islands, could have arisen from tortoises thrown overboard there by 19th century sailors.
For the study, published in the journal Biological Conservation, Yale researchers collected DNA
from more than 1,600 giant tortoises. They discovered that 17 were
ancestors of Lonesome George. The 17
tortoises are hybrids, but evidence suggested a few might be the
offspring of a purebred C. abingdoni parent.
Since five of the
tortoises are juveniles, their parents and hopefully others may still live on the rocky cliffs of
Isabella in an area called Volcano Wolf.
“Our goal is to go back
this spring to look for surviving individuals of this species and to
collect hybrids,” Adalgisa “Gisella” Caccone, senior research
scientist in Yale University's Department of Ecology and Evolutionary Biology and
senior author on the study, was quoted as saying in a press release. “We hope that with a selective breeding
program, we can reintroduce this tortoise species to its native home.”
Volcano Wolf is 37 miles away from Pinta Island, where locals probably hunted Lonesome George's kin there to death. This often happened on islands in the past, unfortunately. With certain species limited to just those locations, and arriving humans facing scant food choices, the combination proved to be a perfect storm for extinction. Even other hominids, like Homo erectus, might have bumped off species in such a manner.
The distance from Pinta, however, provides a clue regarding the latest findings, not to mention Lonesome George.
Volcano Wolf is next to Banks Bay, where in the 19th century sailors of naval and
whaling vessels discarded giant tortoises collected from other islands
when they were no longer needed for food.
A previous genetic analysis of
these same tortoises had discovered tortoises with genetic ancestry of C. elephantopus,
a species from Floreana Island that had been hunted to extinction in
its home range. The members of these marooned tortoise species then
mated with indigenous tortoises, researchers suggest.
We've been following these expeditions for a while, so hopefully we'll soon have other good news to report if the researchers can collect hybrids and possibly even find a purebred Lonesome George relative.
"These giant tortoises are of crucial
importance to the ecosystems of the Galapagos Islands, and the
reintroduction of these species will help preserve their evolutionary
legacy," Danielle Edwards, postdoctoral research associate at Yale and lead author on the study, said.
It's too bad poor George didn't live to see all of this.
(Image of the Late Lonesome George: putneymark)