Several animals once declared extinct have turned up alive, sometimes after decades or even millions of years with no confirmed sightings. These rediscoveries, sometimes called “Lazarus species,” range from deep-sea fish to giant tortoises to insects clinging to a single rocky spire in the Pacific. A handful of other species were driven to the brink, with populations dropping to single digits, before intensive breeding programs pulled them back. Here are the most remarkable cases.
The Coelacanth: 65 Million Years of Hiding
The most dramatic comeback belongs to the African coelacanth, a large, slow-moving fish that scientists believed had gone extinct alongside the dinosaurs roughly 65 million years ago. In 1938, a living specimen was pulled from the waters off the coast of South Africa, stunning the scientific world. A second species was later identified near Indonesia in 1998. Coelacanths live in deep underwater caves and can grow over five feet long, which makes their ability to evade detection for so long all the more remarkable. They remain rare, but stable populations exist in pockets of the Indian Ocean.
Fernandina Island Giant Tortoise
The Fernandina Island Galapagos giant tortoise was known from a single specimen collected in 1906. For more than a century, scientists assumed the species was gone. Then in 2019, a living female was found on the volcanic slopes of Fernandina Island. Genetic analysis published in Nature’s Communications Biology confirmed she belongs to the species Chelonoidis phantasticus, a lineage long considered extinct. Her current known population is technically one individual, but expedition teams have found tracks and scat suggesting at least two or three other tortoises are living somewhere on the island.
Lord Howe Island Stick Insect
This large, shiny black insect, sometimes called a “tree lobster,” was once common on Lord Howe Island in the Tasman Sea. After rats arrived on the island in 1918, the species vanished. It was considered extinct for decades until 2001, when a tiny population was discovered clinging to life on Ball’s Pyramid, a barren volcanic spire 20 kilometers away. Genetic testing confirmed these were the same species, not a lookalike. Individuals from that population are now being bred in captivity in Australia and other countries, with the long-term goal of reintroducing them to Lord Howe Island once the rat population is controlled.
Bermuda Petrel (Cahow)
The Bermuda petrel, locally called the Cahow, was believed extinct for roughly 330 years. Early settlers in Bermuda hunted it heavily in the 1600s, and no confirmed sightings followed for centuries. In 1951, a small number of nesting birds were found on rocky islets in Castle Harbour. The recovery since then has been slow but steady. By 2024, the total number of confirmed breeding pairs reached a record 165 across six nesting islands, and 76 chicks successfully fledged that season. A translocation program has established new colonies on Nonsuch Island, which grew to 40 pairs in 2024.
Species Saved at the Very Edge
Some animals didn’t reappear on their own. They were rescued from functional extinction through captive breeding, and their populations have since been rebuilt.
California Condor
By 1987, only 27 California condors existed on Earth. Every remaining bird was captured for a last-ditch breeding program. The effort worked. As of December 2025, the total world population stands at 607, with 392 living in the wild across California, Arizona, Utah, and Baja California. The remaining 215 are in captive breeding facilities. It is one of the most successful large-bird recovery programs ever attempted.
Black-Footed Ferret
North America’s only native ferret was declared extinct in 1979. Then in 1981, a small colony was found in Wyoming. Disease nearly wiped out that group too, and by 1987 only 18 remained. Every black-footed ferret alive today descends from those 18 individuals, which creates a serious genetic bottleneck. To address that, scientists cloned a ferret named Elizabeth Ann in 2020 using preserved cells from a ferret that died in the 1980s and whose genes are not represented in the current population. In 2024, Elizabeth Ann produced offspring of her own, the first time a cloned endangered animal has successfully bred. By September 2025, additional cloned ferrets named Noreen and Antonia were part of the program, and 12 new kits (6 female, 6 male) were born from ongoing cloning research.
Smaller Rediscoveries You May Not Have Heard Of
Not every comeback makes international headlines. In Baja California, the San Quintín kangaroo rat had not been recorded since 1986 and was listed as critically endangered and possibly extinct. In 2017, researchers from the San Diego Natural History Museum captured several individuals during field surveys in the San Quintín region. On the same series of expeditions, they also rediscovered the tule shrew, another species presumed extinct, surviving in a small patch of habitat south of the Socorro Dunes.
Couch’s spadefoot, a toad-like frog, was reported on Isla Cerralvo off the Baja California coast in 1960. No one saw another one for 56 years. In 2016, a binational survey team found an individual behind the island’s coastal dunes, only the second ever documented on the island.
These cases share a common thread: the animals survived in small, isolated patches of habitat that humans rarely visit. They are reminders that “extinct” sometimes means “not found yet.”
How Scientists Declare a Species Extinct
The International Union for Conservation of Nature classifies a species as extinct when there is “no reasonable doubt that the last individual has died.” That determination requires exhaustive surveys across the species’ entire historical range, conducted at the right times of day, season, and year, over a time frame that reflects the animal’s life cycle. There is no fixed rule like “50 years with no sightings,” though that figure is sometimes cited informally. The bar is deliberately high, which is part of why rediscoveries keep happening. Species that fall in the gray zone are often listed as “critically endangered, possibly extinct” rather than fully extinct.
De-extinction: Bringing Back Lost Species
Beyond rediscoveries and breeding programs, a newer category of “coming back” involves genetic engineering. The most high-profile effort is the woolly mammoth project led by Colossal Biosciences, which aims to create a cold-adapted elephant using genes from preserved mammoth tissue. Asian elephants and woolly mammoths share 99.6% of their DNA. The company is using CRISPR gene editing to modify roughly 65 genes responsible for traits like thick hair, fat storage, and cold tolerance. The plan involves implanting edited embryos into elephant surrogates for a 22-month gestation. No calves have been born yet, but the project has moved through cell-line creation and trait testing.
The Tasmanian tiger, or thylacine, is another de-extinction target. The last known individual died in a Tasmanian zoo in 1936. Scientists now have a chromosomal-level genome of the thylacine and are comparing it to the genome of its closest living relative, the numbat. Recent research published by the Royal Society has mapped gene losses and mutations that made the thylacine unique, including reduced reliance on smell for hunting. This kind of genetic mapping is a necessary step before any attempt at reconstruction, but producing a living thylacine remains years away at best.