The Galapagos Island archipelago is made up of several different islands, with each exhibiting subtle differences that have shaped the evolution of the plants and animals living on them. This has led to several species – including, most notably, Galapagos tortoises (Chelonoidis niger) – evolving into a variety of subspecies, which inhabit different islands in the chain.
For example, the Pinta Island tortoise (C. n. abingdonii) was found only on Pinta Island, while the San Cristóbal giant tortoise (C. n. chathamensis) is limited to Chatham Island.
Because these individual subspecies are all distinct, that means their evolutionary fates are also different. And this means that some may go extinct. For example, the Pinta Island tortoise mentioned above was declared extinct in 2012, when the last confirmed member of the subspecies died.
Typically, once a species or subspecies is declared extinct, that’s it – species don’t come back from the dead, so to speak. But every once in a while, a living representative of a thought-extinct lineage is discovered. And that’s exactly what happened with the Fernandina Island tortoise (Chelonoidis niger phantasticus).
Here I’ll share some fascinating facts about the species and the island it calls home below.
The Fernandina Island Tortoise: Basic Facts
Fernandina Island tortoises are one of the most poorly known tortoise species or subspecies in the world.
In fact, the only specimen ever found – an adult male — was discovered during an expedition to the island in 1906. This individual was captured, euthanized, and preserved (scientists did things a little differently 100 years ago) by the California Academy of Sciences.
Almost everything we know about the subspecies, which is not much, comes from this animal. It is obvious that this subspecies reaches large sizes like most other Galapagos tortoises, and it is colored similarly, except that its face is covered in a yellowish wash.
It is also apparent that this subspecies is one of the saddleback varieties of the Galapagos tortoise. Different subspecies have differently shaped shells, with some featuring relatively typical domed shells and others exhibiting saddle-shaped shells. Typically, animals living on islands with abundant vegetation have domed shells, as there is plenty of ground-level food available for them.
By contrast, those species living on islands with very little vegetation must often stretch their heads high into the trees to collect leaves or fruit. Saddle-shaped shells help in this regard, as they provide greater flexibility with regard to the tortoise’s neck.
In fact, the Fernandina Island tortoise exhibits extreme flaring of the shell margin. This is part of the reason that the subspecies was named “phantasticus,” meaning “fantastic.”
Fernandina Island
At times, it can be helpful to examine an animal’s habitat in hopes of learning more about it. This is especially true in cases where the animal itself is so poorly known, as is the case with Fernandina Island tortoises.
The third largest island of the archipelago, Fernandina Island is approximately 250 square miles in size, and it is located directly west of Isabella – the largest island in the chain. A volcanic island, Fernandina features a 4-mile-wide caldera, which is situated more than 4,000 feet above the surrounding sea.
Fernandina is the youngest of the Galapagos Islands, and it remains an active volcano. In fact, because it is still active, there isn’t a great deal of vegetation on the island; the only vegetation present in many portions of the island exists in small clumps and is separated by large areas of recently congealed lava flow. However, the interior of the island likely harbors much more vegetation.
Reports and Evidence of Fernandina Island Tortoises
While confirmed reports of living tortoises on Fernandina Island remained elusive (in part because the island is so difficult to explore), occasional signs and evidence of the tortoises’ presence were discovered a few times over the last 100 years.
For example, in 1964, researchers found 18 scat samples that appeared to be attributable to tortoises. Later, in the early 2000s, passengers in an aircraft reported seeing a living tortoise, though this could not be confirmed. Another scat sample was found in 2014 and appears to have been left by a tortoise.
Discovery: An Expedition Finds a Living Individual
In 2019, a small group of researchers traveled to Fernandina Island to search for the tortoises. The group did find one living tortoise – a small female specimen, estimated to by more than 50 years old. She was found in an isolated clump of vegetation, which was cut off from the lusher parts of the island by a lava field.
However, finding a tortoise on Fernandina Island does not mean that it was a Fernandina Island tortoise. After all, tortoises occasionally float from one island to another, and humans often brought living tortoises from one island to another for many years during the 1800s. This all means that the tortoise may be a representative of any of the nearby islands, or it could also be a hybrid produced by the mating of two different species.
So, scientists collected DNA samples from the living tortoise (nicknamed “Fernanda”) and compared them with samples of the original Fernandina Island tortoise collected more than 100 years earlier, as well as samples form other living Galapagos tortoise subspecies.
Upon analyzing the samples, the scientists concluded that Fernanda was, in fact, a Fernandina Island tortoise – only the second one known to science.
Is Fernanda an “Endling?”
Scientists have coined the term “endling” to describe the last known individual of a species or subspecies. Lonesome George – a Pinta Island tortoise (C. n. Abingdon) – is perhaps the most famous ending. When he died in 2012, his entire subspecies is thought to have become extinct.
As it stands, Fernanda does appear to be an ending. However, scientists are scouring the planet in hopes of finding others, preferably including males, who may be able to breed with Fernanda. They’re not only making plans to search Fernandina Island, but they’re also searching captive collections in hopes of finding one that was previously misidentified as belonging to another subspecies.
Only time will tell if this subspecies is doomed to extinction or if it may have the chance to live on.
Citations
- Nature — The Galapagos giant tortoise Chelonoidis phantasticus is not extinct
- Gizmodo — ‘Extinct’ Giant Tortoise Was Just Chilling on an Island
- Galapagos Conservancy — The Enigma Of Fernanda – A Lone Survivor In Galápagos
