Floreana giant tortoise: From extinction to return

A subspecies of the Galapagos tortoise

When the Floreana giant tortoise was still alive, it was part of the extraordinary tortoise fauna of the Galapagos Islands. Hardly anywhere else on Earth did a comparable diversity of giant land tortoises evolve—adapted to different islands, volcanoes, climate zones, and food resources.

Today, researchers usually group these forms together as a single species: Chelonoidis niger, the Galapagos giant tortoise. Within this species, about 16 subspecies exist or once existed, often restricted to individual islands or volcanic regions. At present, around twelve populations are still considered extant, while several have already disappeared. Forms known to be certainly extinct include the Pinta Island tortoise (C. n. abingdonii), whose last representative, Lonesome George, died in 2012, as well as the Floreana giant tortoise. The Santa Fe giant tortoise is also considered extinct, although it was never formally described scientifically.

Other forms are taxonomically uncertain. The Rabida Island tortoise (C. n. wallacei) is often listed as extinct, but the origin and distinctness of the underlying type specimens are disputed. The Fernandina giant tortoise (C. n. phantasticus) was long thought lost until a living animal was unexpectedly discovered again in 2019.

The Galapagos giant tortoises are among the largest tortoises in the world: many animals reach more than 400 kilograms in weight and up to 1.20 meters in length. They live to around 100 years of age, and some individuals live much longer. Famous is Harriet, a Santa Cruz giant tortoise (C. n. porteri) that was supposedly collected by Charles Darwin and died in 2006 at the age of about 176.

Despite intensive conservation measures, populations have declined sharply. Over the past three centuries, numbers fell by about 90% (Miller et al. 2017). While probably more than 250,000 animals still lived on the islands in the 16th century, around 20,000 exist again today. Nevertheless, no population is considered fully secure: the IUCN lists all recent forms as vulnerable, endangered, or critically endangered.

Floreana giant tortoise – fact sheet

alternative names	Floreana Island giant tortoise, Charles Island giant tortoise, Charles Island tortoise, Elephant tortoise
scientific names	Chelonoidis niger niger, Chelonoidis niger, Chelonoidis nigra nigra, Chelonoidis nigra, Chelonoidis nigra elephantopus, Chelonoidis nigra galapagoensis, Chelonoidis elephantopus, Geochelone elephantopus, Geochelone elephantopus galapagoensis, Geochelone elephantopus nigra, Geochelone nigra, Geochelone nigra nigra, Geochelone nigra galapagoensis, Testudo galapagoensis, Testudo nigra, Testudo ephippium, Testudo californica, Testudo californiana, Testudo planiceps, Testudo elephantopus, Testudo elephantopus galapagoensis, Testudo elephantopus elephantopus …
original range	Floreana, Galapagos Islands (Pacific Ocean)
time of extinction	between 1840 and 1850
causes of extinction	hunting, introduced island animals, slow reproductive rate
IUCN status	extinct

From mainland tortoises to island giants

The giant tortoises of the Galapagos Islands do not form a separate animal group. They belong to the genus Chelonoidis in the family of tortoises (Testudinidae) and are closely related to species from the South American mainland. These include the yellow-footed tortoise (C. denticulatus) and the red-footed tortoise (C. carbonarius), which share the same evolutionary origin despite their smaller size.

The ancestors of the Galapagos giant tortoises lived on the South American continent. About two to three million years ago, individual animals reached the young volcanic islands of the Galapagos archipelago—probably on drifting mats of vegetation carried hundreds of kilometers by ocean currents. Although tortoises are not active swimmers, they can float on the water for long periods and thus survive great distances.

Once on the islands, the animals were completely isolated. Each island became its own evolutionary experimental space: without genetic exchange with the mainland, without larger enemies, and under different environmental conditions. Over many generations, several specialized island populations developed from the original founder population.

This process is known as adaptive radiation—the splitting of an original species into multiple forms occupying different ecological niches. Similar developments are known, for example, from the Hawaiian honeycreepers or the cichlids of Lake Victoria.

In the Galapagos archipelago, almost every larger island has its own tortoise form. Two islands are exceptions: on the largest island, Isabela, several populations arose because of its five separate volcanoes, while two forms occur on Santa Cruz.

When Charles Darwin visited the Galapagos Islands in the autumn of 1835 during the voyage of the HMS Beagle, he first became aware of these differences. Nicholas Lawson, the then vice-governor of the islands, told him that tortoises from different islands differed clearly and that experienced residents could even recognize which island an animal came from.

Darwin initially attached little importance to this observation. Only later did he recognize its significance. In his travel account, published in 1839, he described the differences between the tortoise populations in detail:

“I never dreamed that islands, about fifty or sixty miles apart, (…) formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted.”

These observations later became an important building block in Darwin’s development of the theory of evolution. The Galapagos Islands now appeared as a place where the emergence of new forms could be traced with particular clarity.

Giant tortoises were once widespread on many islands of the world, for example in the Indian Ocean, on the Mascarenes, in the Caribbean, and even on the Canary Islands. Today, only two lineages remain: the Galapagos giant tortoises in the Pacific and the Aldabra giant tortoise in the Indian Ocean. Many other island populations vanished shortly after the arrival of humans, including the Réunion giant tortoise, the saddle-backed Mauritius giant tortoise, and the domed Rodrigues giant tortoise.

Floreana giant tortoise: morphology and way of life

During the War of 1812, the US Navy officer David Porter operated in the Pacific with the USS Essex. In 1813 and 1814, his expedition stayed on the Galapagos Islands several times. He later published his impressions in the travel account Journal of a Cruise Made to the Pacific Ocean (1815).

Although Porter’s interest was more culinary than zoological, his notes contain some of the earliest descriptions of the archipelago’s giant tortoises. He already noticed differences between the island populations:

“[The tortoises of Hood’s Island] were of a quality far superior to those found on James Island. They were similar in appearance to those of Charles Island, very fat and delicious.”

Porter’s observation suggests that the tortoises of Floreana were externally similar to the still-living animals of Española (C. n. hoodensis).

A more detailed scientific description was later provided by the zoologist John Van Denburgh in his monograph The Gigantic Land Tortoises of the Galapagos Archipelago (1914). He characterized the Floreana giant tortoise as a relatively broadly built animal with a saddle-backed shell, a flat back, and relatively smooth shell plates. At the same time, he emphasized its close relationship to the Española form, but considered the animals from Floreana to be somewhat more robustly built.

As in many tortoise species, the giant tortoises also show clear sexual dimorphism. Darwin already noted this difference during his voyage on the HMS Beagle:

“The old males are the largest, the females rarely growing to so great a size; the male can readily be distinguished from the female by the greater length of its tail.”

Modern studies confirm these differences. In addition to the longer tail and larger size, males also have an inward-curved plastron with thickened projections on the rear edge, which facilitates mating, as well as a flatter carapace.

The characteristic shell shape

The most striking feature of the various island populations is the shape of the upper shell (carapace). In principle, two main types can be distinguished:
– dome-shaped: high-arched, rounded shell
– saddle-backed: elongated shell with a strongly upward-drawn front opening

The extinct Floreana giant tortoise belonged to the group of saddle-backed forms.

Porter already described these differences vividly:

“The form of the shell (…) is elongated, turning up forward in the manner of a Spanish saddle, of a brown color and of considerable thickness. Those of James Island [Santiago] are round, plump, and black as ebony.”

19th-century zoologists such as Albert Günther (1875) also recognized these differences. At first, however, they regarded shell shape merely as a trait for distinguishing individual island populations, without explaining its ecological significance in more detail.

In addition to the classic saddle-backed and dome-shaped forms, the literature also describes intermediate shell forms. Such transitional forms with only a slightly upward-drawn front opening occur, for example, on San Cristóbal and in some populations on Isabela.

Habitat and food

The way of life of the Galapagos giant tortoises is closely tied to the islands’ different environmental conditions. Van Denburgh (1914) noted that tortoises in dry regions feed mainly on cacti of the genus Opuntia, which provide them with both food and water. In the more humid highlands of larger islands, by contrast, they feed mostly on grasses and low-growing plants.

Darwin also described this difference:

“The tortoises which live on those islands where there is no water, or in the lower and arid parts of the others, feed chiefly on the succulent cactus. Those which frequent the higher and damp regions eat the leaves of various trees, a kind of berry (…) aand likewise a pale green filamentous lichen (Usnea plicata) that hangs in tresses from the boughs of the trees.”

Van Denburgh also reported seasonal migrations between dry coastal plains and more humid upland regions. Females sometimes travel several kilometers to reach suitable nesting sites.

Adaptations to dry islands

The explanation now commonly given for the saddle-backed form emerged only in the 20th century. It is usually interpreted as an adaptation to dry habitats.

On low-lying islands such as Floreana or Española, vegetation is sparser and often consists of shrubs or cacti. The upward-drawn front opening of the shell allows the animals to stretch their neck and forelegs farther upward. This enables them not only to graze plants on the ground but also to reach food growing higher up. Saddle-backed tortoises therefore usually have longer necks and limbs than dome-shaped forms.

This construction, however, has a disadvantage: when the animals retract their head and forelegs, a relatively large opening remains above the neck. This is regarded as an indication that over millions of years the tortoises hardly had to defend themselves against larger predators—a typical feature of isolated island ecosystems.

Galapagos giant tortoises also have an extremely slow metabolism and can therefore survive for long periods without food or water—another adaptation to dry habitats.

An alternative explanation

Not all researchers see the saddle-backed form solely as an adaptation for feeding. In 1984, the herpetologist Thomas H. Fritts proposed an alternative hypothesis. According to this idea, shell shape could also be partly related to rivalry between males.

Dominance contests are often decided by raising the neck and front of the body. In such situations, vertical reach of the neck matters more than overall body size. A longer neck and an upward-drawn shell opening could therefore also provide advantages in such encounters. Because many saddle-backed populations live on small, dry islands with limited resources, intense competition between males may have reinforced this effect even further.

Under this interpretation, the characteristic shell shape would be an evolutionary compromise: it allows both greater reach while feeding and advantages in male rivalry.

An early depiction of the Floreana giant tortoise?

Charles Darwin was not the discoverer of the Galapagos giant tortoises. His importance lies rather in being the first naturalist to recognize their geographic differences and discuss their possible role in evolutionary processes. The animals had already been described scientifically decades earlier.

The first formal description of a Galapagos giant tortoise was published in 1824 by the French naturalists Jean René Constant Quoy and Joseph Paul Gaimard, who described the species under the name Testudo nigra. Neither had ever visited the islands themselves; their description was based on museum specimens of unknown origin that were probably brought to Europe by sailors or traders.

Only a few years later, the American naturalist Richard Harlan (1826) published another description under the name Testudo elephantopus. It was based on a living animal owned by the Philadelphia merchant Whitton Evans. Harlan examined the tortoise and published a detailed description along with an illustration made by the physician and naturalist Samuel George Morton, who also lived in Philadelphia.

Harlan could not say, however, which island the animal came from; his publication lists only “Gallapagos Islands” as its origin. Only later did taxonomists attempt to assign it on the basis of the description and the drawing. In 1914, Van Denburgh concluded that Harlan’s animal could fit only two populations: the tortoises of Charles Island (Floreana) or a population in southern Isabela.

More recent historical research by Storrs L. Olson and Johanna R. Humphrey (2017) provides additional clues. Using ship logs and trade records, they reconstructed that one of Whitton Evans’s trading vessels—the America under Captain Isaiah Eldredge—was at the Galapagos Islands in September 1825. This ship very probably visited Floreana, at that time an important provisioning stop for ships in the Pacific, before continuing to Honolulu and then Canton.

It is therefore plausible that Eldredge took a living tortoise as a curiosity back to North America for the shipowner—a common practice at the time. The morphology of the tortoise drawn by Morton also fits this interpretation. The illustration shows a clearly pronounced saddle-backed shell form, in which the front edge of the shell is strongly drawn upward. This shape is typical of the populations of Floreana, Española, and Pinta.

Because Floreana was among the most frequently visited islands, whereas there was no obvious reason to continue on to Isabela, Olson and Humphrey consider it most likely that Harlan’s tortoise in fact came from Floreana. If this reconstruction is correct, Morton’s illustration would represent one of the earliest known scientific images of a Floreana giant tortoise.

Where is the animal described by Harlan today?

Records of donations show that the Academy of Natural Sciences in Philadelphia received a specimen of Testudo elephantopus from “Dr. Harlan” in February 1827—only five months after Harlan’s original description (Olson & Humphrey 2017).

When Van Denburgh inquired in 1914 about the whereabouts of this type specimen, a search was conducted in the academy’s collections. Only “the cleaned leg bones of one side of the body, together with parts of the legs of the other side, to which dried skin still adhered” were found—the remains of a tortoise about the size of the animal described by Harlan. These fragments were interpreted as the remains of a once-mounted specimen that had later fallen apart. They too seem later to have been lost or discarded.

The biologist John B. Iverson published a comprehensive list of the type specimens of all tortoise species in 2022. For Testudo elephantopus, he names no holotype because Harlan had not designated one. Instead, he lists two syntypes: one specimen in the Museum of Comparative Zoology at Harvard (MCZ 11063) and another, probably from the Academy of Natural Sciences in Philadelphia, that is now considered lost.

It is difficult to say where further remains of the Floreana tortoise may be located. The scientific naming of the Galapagos giant tortoises in the 19th century was extremely inconsistent. Numerous names were assigned on the basis of individual animals whose origin was often not documented. Many of the tortoises brought to Europe or North America by sailors can therefore only be assigned to particular island populations with difficulty.

Even so, individual historical specimens may still exist that can be attributed to the Floreana population. These include a shell in the Field Museum of Natural History in Chicago (FMNH 13523), another specimen in Tring, one in the Museum of Comparative Zoology in Cambridge, Massachusetts, and probably another in Salem.

Particularly important is a skeleton collected on Floreana in 1833 by Commodore John Downes during the voyage of the US frigate Potomac and handed over to the Boston Society of Natural History (Steadman 1986). This animal later formed the basis for Georg Baur’s description of the species Testudo galapagoensis in 1889. Because its origin is comparatively well documented, it belongs to the few historical museum specimens that can be assigned to the original Floreana population with high probability.

Current taxonomic status

According to the current 10th edition of Turtles of the World (2025), the Floreana giant tortoise is treated as the subspecies Chelonoidis niger niger—that is, the nominotypical form—which has been extinct since about 1850. Earlier names such as Testudo elephantopus or Testudo californiana are based on problematic or unclear type information and are no longer used today; some are regarded as nomina dubia.

Modern systematics follows a conservative approach: all Galapagos giant tortoises are grouped as subspecies of a single species (Chelonoidis niger).

Yet by the time science began to take a more intensive interest in the giant tortoises of the archipelago, the Floreana population had probably already vanished. This makes it one of the first large vertebrates of the Galapagos Islands to be exterminated shortly after the arrival of humans.

On the extermination of the Floreana giant tortoise

Oceanic islands are among the most fragile ecosystems on Earth. Their isolated position often gives rise to unique animal and plant worlds, yet such communities also react especially sensitively to human interference. The Galapagos Islands, too, lying around 900 kilometers off Ecuador’s Pacific coast, were not spared. Since their discovery by Spanish seafarers in 1535, the archipelago has been increasingly altered by human activities.

How dramatic these interventions could be is shown by the fate of the Floreana giant tortoise. Biologist James Gibbs estimated its original population—based on an average density of about one tortoise per hectare of suitable habitat—at around 8,000 individuals (van Dijk et al., 2017). Only a few centuries later, this population had nearly vanished. By the mid-19th century, the form was considered practically extinct.

Natural causes are considered unlikely. In a study (1986), the paleontologist David Steadman points out that Floreana—unlike some other islands of the archipelago—showed no volcanic activity in historical times.

Instead, humans played the decisive role. Since the 17th century, pirates, whalers, and other seafarers used the Galapagos Islands regularly as a provisioning station. The giant land tortoises were considered ideal provisions: they could survive for months without food or water and could be stored alive on ships.

When the American whaling ship Essex called at Floreana in October 1820, the crew collected additional giant tortoises there for provisions. Before that, the sailors had already taken aboard around 300 animals on Española; roughly 100 more were added on Floreana. During a shore excursion, the boatsteerer Thomas Chappel, described as “very wild and always ready for a joke” (Nickerson ca. 1876), set a fire in the island’s dry scrub that spread rapidly in the dry season and got out of control.

Several years later, the former cabin boy Thomas Nickerson returned to Floreana. In his diary, published around 1876, he wrote:

“On my return to this place many years afterwards the ruin was still visible (…). Neither trees, shrubbery, nor grass have since appeared, and judging from the extent of the desolate ground, there must have been thousands upon thousands of terrapin, birds, lizards, and snakes destroyed (…).”

Whether this fire really destroyed a large part of the tortoise population can no longer be determined with certainty today. What is certain, however, is that at this time the Floreana giant tortoises were already suffering heavily from hunting, habitat alteration, and introduced animals. Their disappearance was ultimately the result of several interacting factors.

“Excellent food”—the Floreana giant tortoise

For centuries, the Galapagos giant tortoises ranked among the most important food sources for seafarers in the eastern Pacific. Whaling ships often stayed at sea for months or even years while hunting sperm whales and processing them into whale oil—then a sought-after raw material for oil lamps and soaps (Patowary 2018). Only when their holds were filled with barrels did they return to their home ports.

During this time, the remote Galapagos Islands served many ships as a provisioning station. As early as the late 17th and early 18th centuries, pirates and privateers regularly called at the archipelago to take on supplies and repair their ships. Steadman (1986) suspects that Floreana was already visited in 1687 by the privateer Edward Davies, who captured numerous giant tortoises there—possibly the earliest documented case of hunting this population.

By the end of the 18th century at the latest, the waters around the Galapagos Islands increasingly came into the focus of American and British whalers. Floreana became an important stopover because the island offered fresh water, good anchorage, and large stocks of giant tortoises (Steadman 1986).

Giant tortoises as a source of fresh meat and a water reservoir

For sailors, the animals were an exceptionally practical food source. The animals could survive for months without food and water and could therefore be stored alive in ships’ holds. Captain Benjamin Morrell wrote in 1832:

“They are excellent food and have no doubt saved the lives of thousands of seamen (…). I have known whale-ships to take from 600 to 900 of the smallest size of these tortoises on board when about leaving the islands for their cruising grounds; thus providing themselves with provisions for six or eight months, and securing the men against the scurvy.”

cited in Baur 1889

Darwin also observed a remarkable adaptation of these animals during his 1835 visit: giant tortoises could take in large quantities of water and store it in their bodies. This ability allowed them to survive even on islands without permanent freshwater sources.

For humans, this trait made the animals even more valuable. Sailors used them not only as a meat reserve, but in emergencies also drew on the stored water. Darwin reported:

“The inhabitants, when walking in the lower district, and overcome with thirst, often take advantage of this circumstance, and drink the contents of the bladder (…). The inhabitants, however, always first drink the water in the pericardium, which is described as being best.”

Other observers also confirmed the animals’ extraordinary hardiness. The American naval officer David Porter wrote in 1815:

“(…) for I have been well assured that they have been piled away among the casks in the hold of a ship, where they have been kept eighteen months, and when killed at the expiration of that time, were found to have suffered no diminution in fatness or excellence.”

Besides water and meat, a tortoise also supplied large quantities of fat. Former cabin boy Thomas Nickerson reported that in addition to abundant meat, one animal could also yield “eight to ten pounds of fat.” Porter even described the rendered fat as an oil that was “superior in taste to olive oil.”

Steadman (1986) states that inhabitants of various Galapagos islands regularly killed tortoises in large numbers solely for oil extraction. Particularly prized, he says, were the animals from the islands of Floreana and Española. Porter also remarked that the tortoises from these islands were “far superior to those of James Island [Santiago] in point of fatness.”

These traits made giant tortoises an ideal resource for seafarers: they could be transported alive, required hardly any care, and at the same time provided meat, fat, and in emergencies even drinking water.

Systematic use of the tortoises by island residents

It was not only whaling ships that made intensive use of the giant tortoises—the inhabitants of the archipelago also lived from them. When Darwin arrived on the Galapagos Islands, their use was already highly organized. On James Island (Santiago), he met men from the settlement on Charles Island (Floreana) who were hunting tortoises and preserving meat:

“We found here a party of Spaniards, who had been sent from Charles Island to dry fish and to salt tortoise-meat.”

Darwin describes how systematically the animals were selected:

“When a tortoise is caught, the man makes a slit in the skin near its tail, so as to see inside its body, whether the fat under the dorsal plate is thick. If it is not, the animal is liberated (…).”

This practice shows just how much the animals were already viewed as a mere resource — and not least how defenseless they were against humans. Darwin also found from conversations with island residents that the reptiles had already become much rarer, yet still remained the most important animal food of the local inhabitants:

“Their numbers have of course been greatly reduced in this island, but the people yet count on two days’ hunting giving them food for the rest of the week.”

When stocks declined sharply around 1840, Floreana may have lost importance for whalers, but because of its freshwater sources and vegetable gardens it remained an important port of call (Steadman 1986).

The scale of extraction

The scale of exploitation can today be reconstructed not only from travel accounts but also from historical ship logs. The US zoologist Charles Haskins Townsend evaluated several whaling logbooks in the early 20th century, combing through old ship journals for entries such as terrapin, turpin, or tortoise—period terms for tortoises. In his essay The Galapagos Tortoises in their Relation to the Whaling Industry (1925), he documented numerous removals. According to the logbook, the American whaler Moss took a total of 350 tortoises from Floreana aboard between February 15 and 24 and again on March 1, 1834.

At the same time, numerous other whaling ships called at the island in the early 1830s. Steadman (1986) compiled a list of known removals between 1812 and 1837. Between October 1832 and August 1833 alone, at least 31 whaling ships visited Floreana.

If each of these ships took, as contemporary estimates suggest, an average of about 138 tortoises, whalers may have removed almost 5,000 animals from the island within a single year. For a population that probably numbered only a few thousand animals, such a removal rate must have had devastating consequences.

These figures represent only part of the true scale. The zoologist Georg Baur estimated in 1889 that at least 100,000 giant tortoises had been taken since the discovery of the Galapagos Islands; later he revised his estimate upward to ten million. The actual number can no longer be reconstructed, but Steadman considers it likely to lie somewhere between these two extremes.

Further clues come from historical reports. Porter, for instance, wrote that in 1813 there were large concentrations of tortoises at waterholes on Floreana, from which 400 to 500 animals were later taken aboard. Darwin also reported that individual ships had once taken up to 700 tortoises from Floreana and that a frigate crew once brought 200 animals to the shore in a single day.

The zoologist Igor Akimushkin also evaluated historical logbooks. According to him, 79 whaling ships alone took a total of 13,013 tortoises from the Galapagos Islands between 1831 and 1868. At that time, the American whaling fleet comprised about 700 ships, to which must be added vessels of other nations as well as earlier pirates and privateers. Akimushkin therefore estimated that seafarers of past centuries captured several million giant tortoises as provisions—including island populations in the Indian Ocean.

The zoologist Igor Akimushkin (1981) also evaluated historical logbooks. According to him, 79 whaling ships alone took a total of 13,013 tortoises from the Galapagos Islands between 1831 and 1868. At that time, the American whaling fleet comprised about 700 ships, to which must be added vessels of other nations as well as earlier pirates and privateers. Akimushkin therefore estimated that seafarers of past centuries captured several million giant tortoises as provisions—including island populations in the Indian Ocean.

The massive hunting was the main cause of the disappearance of the Floreana giant tortoise. But introduced livestock, competition for waterholes, and changes in vegetation likely also prevented the recovery of the remnant population. The combination of direct exploitation and ecological transformation ultimately led to the collapse of the Floreana population.

Invasive species: unseen contributors to extinction

At first glance, it seems unlikely that introduced animals could have posed a serious threat to giant tortoises. Adult Galapagos giant tortoises are among the largest reptiles in the world and are protected from most enemies by their massive shells. Nevertheless, invasive animal species probably played an important—though mostly indirect—role in the disappearance of the Floreana giant tortoise.

Around 1832, numerous domestic animals were introduced to Floreana, including pigs, dogs, cats, goats, cattle, and donkeys; at roughly the same time, house rats and mice probably also reached the island (IUCN). Many of these animals quickly went feral and spread across the island.

Steadman (1986) emphasizes that although the extinction of the Floreana giant tortoise was due primarily to direct human hunting, Floreana was altered by introduced mammals more strongly than almost any other island in the archipelago. Such species can be especially destructive to isolated island ecosystems and are probably connected with the disappearance of at least six vertebrate species on Floreana—even if direct proof is often difficult to provide in individual cases.

Predation on eggs and hatchlings

While adult giant tortoises had hardly any natural enemies, their eggs and young were extremely vulnerable. Introduced mammals could therefore have had a substantial impact on the tortoises’ reproductive success.

According to Steadman (1986), rats in particular may have contributed to the population’s decline by eating eggs and newly hatched young. Similar connections are known from many other islands where introduced rat populations led to the collapse of bird and reptile populations.

Feral cats and dogs probably also caused damage. Historical reports show that cats on Floreana regularly hunted native birds such as finches and doves. Steadman suggests that they may also have preyed on young giant tortoises and other native vertebrates.

Pigs may also have played a special role. As omnivores, they root through the soil in search of food and in doing so often destroy tortoise nests. They eat eggs and also kill hatchlings. The biologist Carl B. Koford (1966) reported that residents of Santa Cruz in the Galapagos confirmed this behavior of feral pigs.

Destruction of vegetation

Probably even more serious than direct predation were the habitat changes caused by introduced herbivores. Goats, cattle, and donkeys multiplied rapidly on Floreana and ate large parts of the native vegetation. Goats in particular are considered one of the most destructive invasive species on islands worldwide, because they can drastically alter entire landscapes within just a few decades.

In the dry regions of the Galapagos Islands, cacti of the genus Opuntia are among the most important food sources for giant tortoises. Yet these succulent plants are also especially heavily browsed by goats. According to Steadman, studies show that introduced herbivores caused major damage to vegetation on several Galapagos islands—including Santa Cruz, Santa Fe, and Pinta. Similar processes are likely to have occurred on Floreana as well.

Donkeys and cattle intensified this effect even further. Koford (1966) found that Floreana at times had the highest donkey density in the entire archipelago. Large herds of feral hoofed animals destroyed vegetation, compacted the soil, and competed with tortoises for food and water.

Historical reports show how quickly these introduced animals spread. As early as 1835, Darwin observed feral goats and pigs on Floreana—although the island had only been settled a few years earlier. The naturalist Berthold Seemann reported in 1846 that no tortoises were left on Floreana, while “wild dogs, pigs, goats, and cattle had multiplied astonishingly” there (Van Denburgh 1914).

When Captain A. H. Markham visited the island in 1880 with the HMS Triumph, it was, in his words, “in the undisturbed possession of wild cattle (…) as well as donkeys, dogs, pigs, and other animals.” Later visitors also reported large populations of feral livestock and introduced rodents. By the end of the 19th century, numerous invasive mammals were permanently established on Floreana.

Slow reproduction of giant tortoises

An important reason for the Floreana giant tortoise’s vulnerability to human impacts was its very slow reproductive rate—a trait typical of many large and long-lived animal species. Galapagos giant tortoises probably reach sexual maturity only at 30 to 40 years of age.

Egg-laying usually takes place between July and November. To do this, females dig a nesting chamber about 30 centimeters deep with their hind legs, into which they lay their eggs. Research by MacFarland et al. (1974) shows that clutch size differs markedly between tortoise populations. Species with dome-shaped shells lay an average of nine to ten eggs, whereas saddle-backed forms usually produce only four to five eggs per clutch. A female can lay one to four clutches per season. For the saddle-backed Floreana giant tortoise, this yields an annual production of about four to 20 eggs. Incubation lasts four to eight months, or up to about 250 days. Newly hatched young are only a few centimeters long and often weigh no more than 50 grams.

The first years of life are especially risky for the young. Darwin reported as early as 1835 that many newly hatched tortoises were preyed on by the Galapagos hawk. Later field studies, however, were barely able to confirm this assumption (MacFarland et al. 1974). Hawks were repeatedly observed near young tortoises, but documented attacks are rare. A considerable proportion of the young instead appears to die mainly of food shortage in dry years. In addition, introduced predators such as rats, cats, and pigs likely preyed on both eggs and hatchlings.

The combination of late sexual maturity, small clutches, and high juvenile mortality means that populations of giant tortoises can recover only very slowly. At the same time, adult animals can live for more than a century. This long lifespan can initially mask a population decline: even if many adults are still present, the number of young may already be too low to secure the population in the long term.

The low reproductive rate was therefore likely—alongside intensive hunting, introduced predators, and habitat change—a decisive factor contributing to the extinction of the Floreana giant tortoise.

Island tameness as a death sentence?

For many thousands of years, the giant tortoises of the Galapagos Islands lived in an environment with only a few natural enemies. For fully grown animals, there were practically no serious predators; deaths among adults were rare and usually accidental—for example falls from rocks or other mishaps.

Large land predators were entirely absent on the isolated islands. There were neither hunting mammals nor other apex predators. Under such conditions, there was hardly any evolutionary pressure over millions of years to develop a pronounced escape response toward large animals.

Darwin described the tortoises’ behavior during his visit in 1835:

“The inhabitants believe that these animals are absolutely deaf; certainly they do not overhear a person walking close behind them. I was always amused when overtaking one of these great monsters, (…) to see how suddenly, the instant I passed, it would draw in its head and legs, and uttering a deep hiss fall to the ground with a heavy sound.”

Darwin’s observation shows that the animals did react to threats—but usually only at the very last moment. Their defensive strategy did not consist of flight, but of passive withdrawal into the protective shell.

Even if they had wanted to flee, their chances would have been poor. The body plan of giant tortoises is adapted for protection and longevity, not for speed. The animals move slowly and clumsily and can hardly escape a human. In a world without larger predators, this strategy was successful; with the arrival of humans, however, it became a disadvantage.

The US Navy officer David Porter described similar impressions:

“In the daytime, they appear remarkably quick-sighted and timid, drawing their head into their shell on the slightest motion of any object; but they are entirely destitute of hearing, as the loudest noise, even the firing of a gun, does not seem to alarm them in the slightest degree, and at night or in the dark they appear perfectly blind.”

Porter’s description confirms Darwin’s impression: the giant tortoises did have simple protective reactions, but evolution had not prepared them for a new, fast, and intelligent hunter. Their strategy was to wait out danger—a behavior that worked against natural enemies, but was apparently ineffective against humans.

Not actual “island tameness” in the sense of a lack of caution, but above all the absence of an ability to flee made the animals especially vulnerable. When humans began hunting the tortoises systematically, they could offer little resistance to this threat. In combination with their slow reproduction, the intensive exploitation by seafarers, and the changes to their habitat, this evolutionary adaptation ultimately became a decisive factor in their disappearance.

When did the Floreana giant tortoise go extinct?

Van Denburgh (1914) noted that the Galapagos Islands remained largely uninhabited until the early 19th century. Apart from individual adventurers—such as the Irishman Patrick Watkins, who settled on Floreana in 1809—there were no permanent settlements. Only in the 1830s did the systematic colonization of the archipelago begin.

The fossil record, however, indicates that the Floreana giant tortoise was once extraordinarily common. In four lava tunnels, Steadman (1986) documented more than 260 individuals on the basis of over 6,500 bone fragments. This makes the species the most frequent vertebrate form in the fossil material studied—an indication of a formerly large population.

For much of the 18th century, the removal of giant tortoises was probably still comparatively low, since only a few ships called at the archipelago. Only with the rise of British and American whaling toward the end of the century did pressure on the populations increase markedly.

Around 1800, the Floreana giant tortoise still appears to have been abundant. Several travel accounts document large stocks. E. C. Cornell reported freshly hatched young on the island in 1816 (Townsend 1915), and the American seafarer Amasa Delano wrote in 1817 in Narrative of Voyages and Travels that giant tortoises were common on Floreana, Española, and Isabela. Other contemporary sources also confirm the abundance of the animals at the beginning of the 19th century (Van Denburgh 1914).

Porter described large gatherings of the animals at waterholes in 1813/14:

“It abounds with tortoises, which frequent the springs for the sake of the water, and upwards of thirty of them were turned on their backs by us, as they came down to drink, during the short time we remained there, which was not more than an hour and a half. (…) Later, between four and five hundred were taken on board.”

First signs of decline

Only a few years later, signs of a sharp decline appear. The cabin boy Thomas Nickerson, who visited Floreana in 1820, wrote:

“We obtained one hundred terrapins at this island but found them to be very scarce.”

This statement is remarkable: even a severely reduced population apparently still allowed high catch numbers in the short term. The claim that the animals were “very scarce” despite 100 being captured is an indication of how large the original stocks must have been. It also shows that the decline had already begun before 1820.

Colonization and collapse of the population

A decisive turning point was the establishment of a colony on Floreana in 1832. The Ecuadorian entrepreneur and general José de Villamil received permission from the government to found a settlement there. According to Darwin, about 200 to 300 people were living on the island in 1835.

With the settlers came livestock such as goats, pigs, and cattle, as well as numerous introduced plants. Villamil’s colony is said at times to have possessed around 2,000 cattle, many of which later went feral. At the same time, the colonists intensively used the giant tortoises as a food source. In addition, the foundation of the settlement also caused the number of whaling ships calling at Floreana to rise sharply. Besides water and tortoises, ships could now also acquire fresh fruit and vegetables.

Only a few years later, stocks had been reduced so drastically that residents had to send hunting expeditions to other islands in order to obtain enough meat (Van Denburgh 1914). Darwin, too, encountered men from Floreana hunting tortoises on the island of Santiago in 1835.

When Darwin himself landed on Floreana in 1835, he saw no living tortoises, but noted that they still remained the residents’ most important animal food.

The captain of the Beagle, Robert FitzRoy, later noted:

“The quantity of tortoise shells lying about the ground, shows what havock has been made among these helpless animals.”

Darwin also wrote of the island:

“Where the settlement now is (…) [tortoises] formerly swarmed.”

The vice-governor Nicholas Lawson thought at the time that enough animals remained for about 20 years—an assessment that in hindsight proved too optimistic.

The disappearance of the last animals

Shortly after Darwin’s visit, the population appears to have collapsed completely. In the whaling logbooks evaluated by Townsend, there are no more documented tortoise catches on Floreana after 1837. When the French frigate La Venus visited the island in 1838, birds and plants were collected, but tortoises were no longer mentioned (Steadman 1986).

The colony itself was moved to the neighboring island of San Cristóbal in 1845 or 1846, while Floreana remained inhabited only sporadically. By that point, the original tortoise population had already collapsed.

When the British ship HMS Herald visited the island in 1846, Berthold Seemann explicitly reported that no giant tortoises lived on Floreana anymore , whereas feral dogs, pigs, goats, and cattle were abundant (Van Denburgh 1914). Barely 15 years lie between the documented mass catches of the 1830s and this observation.

Confirmation by later expeditions

Later expeditions also failed to detect any living animals. Zoologist Johan G. H. Kinberg found no tortoises on Floreana in 1852 during the Swedish Eugenie expedition. Some later reports do mention isolated animals—for example one specimen supposedly acquired by Louis Agassiz in 1872, or three animals captured by the whaler Atlantic in 1882. In Van Denburgh’s view, however, these were probably tortoises that had been brought to Floreana from other islands. Further expeditions confirmed this picture.

Albert Günther wrote in 1875 in a treatise that the Floreana form was probably extinct; Georg Baur confirmed this assessment in 1889. Even during a stay of several months on the Galapagos Islands in 1891 , Baur and C. F. Adams were unable to find any animals on Floreana.

An expedition commissioned by the British zoologist Lionel Walter Rothschild searched numerous islands of the archipelago from 1897 to 1898, but found giant tortoises only on Isabela and Pinzón.

The extensive Galapagos expedition of the California Academy of Sciences (1905–1906) found neither living animals nor fresh remains on Floreana despite months of fieldwork. Even in remote regions of the island where animals might theoretically have persisted, no trace was found.

Van Denburgh later evaluated the results of this expedition and in 1914 came to an unequivocal conclusion: No reproducing population still existed on Floreana.

When exactly did the species disappear?

Most historical sources indicate that the Floreana giant tortoise went extinct between about 1840 and 1850. It had probably already become extremely rare by the 1830s.

Within just a few decades, the picture had changed fundamentally: a once-abundant island population had first become a scattered remnant population—and finally none at all. For the Floreana giant tortoise, any rescue came too late.

The return of the Floreana giant tortoise

For more than 160 years, the Floreana giant tortoise was considered definitively extinct. Since the middle of the 19th century, no living animal had been seen on its home island. The species seemed lost—until a surprising discovery was made in 2000.

A discovery at Wolf Volcano

On the remote northern flank of Wolf Volcano on Isabela Island—a hard-to-reach landscape of lava fields, thorn scrub, and cloud forest—researchers led by the biologist James Gibbs came across an unusual group of giant tortoises.

Among thousands of locally endemic Volcán Wolf giant tortoises (C. n. becki) with saddle-backed shells, they found individual animals that differed morphologically from the local population—a first indication of an external origin.

Gibbs noted in his field diary:

“This morning we headed up the old hunter’s trail and, much to our surprise, where there were no tortoises the few days before suddenly they were all over. There were tiny ones and big ones, males and females, tortoises all over … we then got serendipitously sidetracked and found ourselves in the thick of many highly sculpted and saddle-backed tortoises on a side slope to the volcano.”

This striking mixture of different shell forms was biologically unusual and raised a crucial question: Where did these animals come from?

First genetic clues (2002)

A genetic study by Adalgisa Caccone and colleagues (2002) examined the mitochondrial DNA of tortoises from across the archipelago. It showed that the population at Wolf Volcano is a genetic mosaic.

Alongside the local Wolf lineage, lineages from other island populations were found there—for example from Española, San Cristóbal, and Santiago. Evidently, numerous animals lived on Isabela whose ancestors had originally come from other islands.

At that time, however, the Floreana lineage could not yet be identified unequivocally. Comparative data from museum collections were lacking, the genetic methods were still limited, and most descendants were genetically heavily mixed.

How did the tortoises get to Isabela?

To understand these mixed populations, it must be clarified how giant tortoises could reach other islands. According to Caccone et al. (2002), there are fundamentally two possible routes: natural drifting and human transport.

Although they are poor swimmers, Galapagos giant tortoises can drift at sea, keep their heads above water, and survive for months without food or drinking water. Ocean currents could therefore have transported individual animals between islands. The ancestors of today’s giant tortoises probably reached the archipelago in this way two to three million years ago.

Much more likely, however, is human-mediated dispersal. Between the 17th and 19th centuries, whalers and seafarers collected tens of thousands of giant tortoises as living meat supplies. Animals were transported between islands, stored temporarily, or thrown overboard for practical reasons to lighten the load during escapes or conflicts.

Some of these animals survived on new islands and mixed with local populations. What once contributed to their downfall became centuries later a means of their rescue.

Genetic detective work for a vanished species (2008)

A decisive study was published by Nikos Poulakakis in 2008. The researchers analyzed mitochondrial DNA from 25 historical museum specimens of the Floreana giant tortoise and compared it with genetic data from living animals.

The results first showed that the historical Floreana population represented a clearly distinct evolutionary lineage. Genetically, it differed clearly from all other island populations. It also possessed morphological peculiarities: its shell was saddle-backed, but conspicuously flat and irregularly shaped. Some researchers therefore regard it as a separate species (for example as Chelonoidis elephantopus), while others treat it as a subspecies within the Chelonoidis niger complex.

But the genetic analyses produced an even more surprising insight: on Isabela, specifically at Wolf Volcano, tortoises were indeed living with genetic markers of the extinct Floreana lineage. The species had therefore not disappeared completely—its genes had survived in a hybrid population.

A large expedition to Wolf Volcano

To investigate the extent of this genetic mixing, a major expedition to Wolf Volcano was launched in 2008. A team led by Ryan C. Garrick genetically examined 1,669 saddle-backed tortoises, about 20% of the entire population.

The results, published in 2012, showed:
– 105 animals were genetically mixed
– 84 individuals were hybrids with Floreana or Pinta genetic components
– among these hybrids, at least one parent must have had a pure Floreana lineage

Most of these animals were found on the western slopes of the volcano near Banks Bay (Puerto Bravo) and Piedras Blancas.

Purebred Floreana tortoises could not be identified unequivocally. Yet the age structure was remarkable: 30 of the hybrids were younger than 15 years. Because giant tortoises can live for more than 100 years, there remained the possibility that genetically pure animals still existed—or had existed until very recently. The analyses also showed that hybridization had repeatedly occurred for about 200 years—probably since the time of the whalers.

The expedition of 2015

In 2015, another targeted expedition to Wolf Volcano followed. The scientists focused on tortoises with saddle-backed shells, especially in regions where hybrids had previously been found.

In total, 144 animals were genetically examined. The analyses (2017) by the research team around Joshua M. Miller showed:
– 35 animals possessed a Floreana-typical mitochondrial lineage
– 127 individuals carried nuclear ancestry from the Floreana population
– 2 animals showed a very high genetic match with the Floreana lineage
– 23 animals belonged exclusively to the local Wolf population

That made one thing clear: The genetic legacy of the Floreana giant tortoise still exists.

The breeding program

From the examined animals, 23 individuals (9 males, 14 females) were selected that possess especially high proportions of the Floreana lineage. They form the foundation of a controlled breeding program. More than 40 additional suitable candidates still live at Wolf Volcano and could be incorporated into the program in the future.

The aim is to
– preserve as much Floreana genetic material as possible
– maintain genetic diversity
– avoid inbreeding
– build up, in the long term, a population for the reintroduction to Floreana

In doing so, the researchers are not relying on genetic engineering but on classical breeding methods. By selectively pairing animals with a high proportion of Floreana genes, that proportion is intended to increase from generation to generation. Unlike the back-breeding projects for aurochs or quagga, the focus here is not on the species’ external appearance but on its genetic background.

Today’s animals are estimated to carry 40 to 80% of the original Floreana genetic heritage. The goal is therefore not a perfect reconstruction of the historical population, but the closest possible genetic approximation.

Reintroduction on Floreana

By 2025, more than 600 young tortoises had been born at the breeding center on Santa Cruz. Around 300 of them are now large enough for release.

In February 2026, tortoises of the Floreana lineage were released on their home island for the first time in around 180 years: 158 animals aged eight to 13 years were released during the rainy season, when food and living conditions are especially favorable. The reintroduction is part of the Floreana Island Ecological Restoration Project and represents the first of twelve planned releases.

All animals carry GPS transmitters to monitor their movements and health status. According to James Gibbs (2026), 25 to 100 more animals are to follow each year in the coming decades in order to build a stable population once again in the long term.

Why the return of the tortoises is crucial

When the Floreana giant tortoise disappeared in the 19th century, the island lost not only one animal species but a central ecological force. Giant tortoises are mega-herbivores and are considered keystone species. They graze vegetation, keep areas open, trample dense scrub, create clearings, and disperse seeds over long distances. Many plant species depend on their seeds passing through a tortoise’s digestive tract in order to become capable of germination or to reach new sites.

With the disappearance of the tortoises, Floreana’s vegetation changed markedly. Shrubs spread more densely, open areas declined, and the composition of plant species shifted. Without large-scale seed dispersal, an important engine for the regeneration of native vegetation was lost—with consequences for numerous animal species.

At the same time, invasive species such as rats, mice, and feral cats worsened the situation. They ate eggs, young animals, and seeds, reduced populations of native species, and interrupted ecological processes. Over decades, a disturbed ecosystem emerged.

The Floreana Ecological Restoration Project is now trying to reverse this development. In a first step, invasive species—especially rats and feral cats—are being systematically removed. Initial results already show positive effects: bird populations are increasing, species previously rare or missing are being observed again, and agricultural yields as well as human health are also benefiting.

But even the removal of invasive species cannot fully restore the original ecological balance. One central actor is missing: the giant tortoise. With its return, lost ecological processes begin to function again. The animals open dense vegetation, promote the germination of certain plant species, and transport seeds into new habitats. In this way, they stabilize the island’s vegetation structure over the long term.

Birds, reptiles, and insects benefit in turn. At the same time, soil stability and nutrient cycles improve. Seabirds bring nutrients from the sea onto land and thus connect marine and terrestrial ecosystems.

The return of the tortoises thus restores lost ecological functions and strengthens Floreana’s biodiversity over the long term. This is not a genetic “resurrection,” but the return of a functionally and genetically closely related lineage capable of taking over the role once played by the extinct species.

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