The thylacine (Thylacinus cynocephalus) was the largest carnivorous marsupial to survive into modern times — a dog-sized predator distinguished by 13 to 21 dark stripes across its lower back and tail, which earned it the names Tasmanian tiger and Tasmanian wolf. Despite the canine resemblance, it was a marsupial, more closely related to kangaroos and Tasmanian devils than to any placental dog, and it carried its young in a backward-opening pouch. By the time of European settlement it survived only on the island of Tasmania, having vanished from mainland Australia and New Guinea thousands of years earlier.
Its disappearance from the mainland is generally attributed to a combination of competition with the dingo, growing human populations, and climatic shifts in the late Holocene; the most recent mainland remains are roughly 3,000 years old. On Tasmania, which the dingo never reached, the thylacine endured into the twentieth century, only to collapse with extraordinary speed once it was framed as a threat to colonial sheep flocks.
From the 1830s onward, private companies and then the government placed bounties on the animal. The Tasmanian Parliament approved a government bounty in 1888 that paid £1 per adult scalp (and ten shillings per juvenile), and over roughly two decades the scheme paid out on more than 2,000 animals. Combined with habitat loss, competition with introduced dogs, and a probable distemper-like disease that swept the population around 1900–1910, this persecution drove the species to the brink.
The last known thylacine died in captivity at the Beaumaris Zoo in Hobart on the night of 7 September 1936 — fewer than two months after the species had finally been granted legal protection. No confirmed living specimen has been documented since, though unverified sightings have persisted for decades, and the species has become a focus of de-extinction interest in the twenty-first century.
Steller’s sea cow (Hydrodamalis gigas) was a giant cold-water sirenian, a relative of the living manatees and dugongs, that grazed on kelp in the shallow coastal waters of the Bering Sea. Reaching lengths estimated at eight to nine meters and weights of several tonnes, it was by far the largest sirenian of recent times and one of the largest marine mammals outside the whales.
The species was made known to science in 1741, when the naturalist Georg Wilhelm Steller observed it during Vitus Bering’s expedition, after the ship wrecked and the crew was stranded on what is now Bering Island in the Commander group. By that time the animal already appears to have been a relict, confined to the waters around the Commander Islands, with a population estimated at only around 1,500 to 2,000 individuals.
Large, slow, buoyant, and seemingly unafraid of humans, the sea cow was extraordinarily easy to kill. Fur-hunting and sealing crews working the newly opened North Pacific route slaughtered it for its meat and its thick fat to provision their voyages. Within roughly 27 years of Steller’s first description, around 1768, the species was gone.
Steller’s sea cow has become the textbook example of rapid post-contact extinction: a large, conspicuous animal driven from scientific discovery to total disappearance in under three decades, documented almost entirely by the single naturalist who first described it.
The quagga (Equus quagga quagga) was a subspecies of the plains zebra native to the dry Karoo and the grasslands of South Africa’s Cape, ranging largely south of the Orange River. It was distinguished by a striking, incomplete coat: bold brown-and-white stripes on the head and neck that faded progressively down the body and dissolved into a plain reddish-brown on the hindquarters and legs, which appeared almost horse-like. Its common name, transcribed from a Khoikhoi word, was onomatopoeic, imitating its barking call, rendered as “kwa-ha-ha.”
Through the first half of the nineteenth century the quagga was hunted intensively by European settlers, principally for its meat and hide and to remove a grazing competitor with domestic sheep and goats. Because contemporary observers used the word “quagga” loosely for several kinds of zebra, the animal’s status as a distinct form was poorly understood, and its disappearance from the veld went largely unremarked at the time.
The last wild quaggas were extirpated in the late 1870s; the final wild individual is generally reckoned to have died around 1878. A handful of captive animals lingered in European zoological gardens, the last of them a mare at the Natura Artis Magistra zoo in Amsterdam, who died on 12 August 1883. No one at the time recognized that her death marked the end of the subspecies.
The quagga survives today only as roughly two dozen mounted specimens, a few skeletons, and a small set of photographs of a single living animal taken in London. It holds two distinctions in the history of extinction: in 1984 it became the first extinct animal to have its DNA studied, and since 1987 it has been the subject of the Quagga Project, a long-running attempt to breed back its distinctive coat pattern from living plains zebras.
The Pyrenean ibex (Capra pyrenaica pyrenaica), known in Spanish and Aragonese as the bucardo, was one of the subspecies of the Iberian ibex, a wild goat of the mountains of the Iberian Peninsula. It inhabited the high country of the Pyrenees in northern Spain and the far south of France, where males carried large, thick horns that curved outward, back, and up.
From the nineteenth century onward the bucardo was reduced by hunting and competition with domestic livestock until it survived only as a small remnant in and around Ordesa y Monte Perdido National Park in the Spanish Pyrenees. By 1900 fewer than a hundred remained, and from 1910 the population is reported never to have risen above forty. Across the twentieth century the numbers slid steadily downward, to a handful and finally to a single animal.
That last individual, a female named Celia, was captured and radio-collared in 1999 so that biologists could monitor her. On 6 January 2000 she was found dead, crushed beneath a fallen tree. With her death the subspecies became extinct — but, unusually, her cells had been preserved.
In 2003 a team of Spanish and French scientists used those cells to clone Celia, and a cloned kid was born alive on 30 July 2003. It died within minutes from a lung defect. The bucardo thus became the first extinct animal brought back, however briefly, through cloning — and the only one to have gone extinct twice.
The baiji (Lipotes vexillifer) was a freshwater dolphin endemic to the Yangtze River in China, the sole member of the family Lipotidae and a lineage that had diverged from other river dolphins some sixteen to twenty million years earlier. Pale grey above and white below, with very poor eyesight and a long, slightly upturned beak, it navigated the murky river largely by echolocation. In Chinese tradition it was revered as the “Goddess of the Yangtze.”
As China industrialized, the baiji was caught between many pressures at once. It was killed by entanglement in fishing gear, especially rolling-hook longlines, and increasingly by electrofishing; it was struck by the heavy boat traffic of one of the world’s busiest rivers; and its habitat was degraded by dam construction, pollution, and dredging.
The population fell with terrible speed: from an estimated 6,000 animals in the 1950s to roughly 400 by 1980, and to just 13 confirmed in a survey of 1997. A six-week international survey in late 2006 covering the dolphin’s entire historical range in the main Yangtze channel found not a single baiji.
On the basis of that survey the species was declared functionally extinct in a 2007 paper — the first cetacean driven to extinction by human activity in modern times, and the disappearance of an entire mammal family. A single unconfirmed sighting was reported in 2007, but no baiji has been verified since.