De-extinction is possible in a limited sense, and scientists are closer than ever to proving it. No one has yet produced a living, surviving member of an extinct species, but the tools to do so now exist, and at least two major projects expect results within the next few years. The real answer depends on what you mean by “possible”: bringing back an exact genetic copy of a vanished species remains out of reach, but creating a functional stand-in that looks, behaves, and fills the same ecological role is genuinely within sight.
Three Paths to Bringing a Species Back
The International Union for Conservation of Nature outlines three methods for generating what it calls “proxies” of extinct species: selective breeding, cloning, and genome editing. Each has different requirements and different limits.
Selective breeding (sometimes called back-breeding) works only when living descendants of the extinct species still exist. You selectively breed individuals that carry ancestral traits until you get an animal that closely resembles the lost species. This approach has been tried with the aurochs, the wild ancestor of modern cattle that went extinct in 1627. It’s the simplest method, but it can only recover traits that still exist somewhere in the gene pool.
Cloning requires intact cells or at least a well-preserved nucleus from the extinct animal, plus a closely related living species to serve as an egg donor and surrogate mother. This is the method that produced the only extinct animal ever born: a Pyrenean ibex (bucardo) cloned in 2003. The clone died of a lung defect minutes after birth. No cloned extinct animal has survived since.
Genome editing is the most versatile approach and the one driving today’s highest-profile projects. Scientists take living cells from a close relative, then use gene-editing tools to swap in DNA sequences recovered from the extinct species. The result isn’t a perfect replica. It’s a hybrid, an engineered animal carrying enough of the extinct species’ genes to reproduce its key traits. This is the only method that works for the majority of de-extinction candidates, since most extinct species don’t have living descendants or preserved cells.
The Woolly Mammoth Project
The most ambitious de-extinction effort targets the woolly mammoth, led by the biotechnology company Colossal Biosciences. Their approach starts with skin cells from Asian elephants, the mammoth’s closest living relative. Scientists edit those cells to carry mammoth genes responsible for traits like cold tolerance, fat storage, and a thick woolly coat. The modified cells are then used to create cloned embryos, which would be implanted in surrogate Asian elephants for a 22-month pregnancy.
Colossal has already validated parts of this process. The company produced genetically engineered “woolly mice,” named Chip and Dale, that grow the same type of coat as woolly mammoths. This confirmed that the team is editing the right genes. In a separate project, Colossal announced it had brought back the dire wolf using similar gene-editing techniques.
The company predicts the birth of its first mammoth-elephant hybrid within roughly two years. That timeline is ambitious, and plenty of hurdles remain. But the financial backing is real: Colossal raised $200 million in a Series C round in January 2025, putting its valuation at $10.2 billion. That level of investment signals that serious people believe this is more than a thought experiment.
Reviving the Thylacine
Australia’s thylacine, or Tasmanian tiger, is the other major de-extinction target. The last known thylacine died in a Hobart zoo in 1936. The TIGRR Lab at the University of Melbourne is working on three fronts simultaneously: sequencing and reconstructing the thylacine genome, developing marsupial stem cells, and building assisted reproductive techniques for marsupials, including potentially an artificial womb. Marsupials give birth to extremely underdeveloped young, which makes surrogate pregnancy more complex than in placental mammals. The thylacine project is earlier-stage than the mammoth effort, but it’s the most serious attempt at reviving a marsupial species.
Why DNA Sets a Hard Time Limit
If you’re wondering about dinosaurs, the answer is a firm no. DNA degrades over time no matter how well it’s preserved. Under normal conditions, DNA survives no more than a few hundred thousand years. Even the half-life of short DNA fragments in bone is only about 500 years, meaning half the fragments break down in that time. Frozen conditions can stretch preservation past a million years, but that’s the absolute ceiling. The oldest credible DNA ever sequenced came from plant and insect material in Greenland ice cores dated between 450,000 and 800,000 years old.
Dinosaurs went extinct 66 million years ago. Their DNA is gone many times over. No amount of technological advancement can recover information that no longer physically exists. De-extinction is limited to species that vanished recently enough to leave recoverable genetic material, or that have close enough living relatives to serve as a genetic starting point.
What “Back” Really Means
One important distinction often gets lost in headlines: de-extinction doesn’t recreate the original species. It creates what scientists call a functional proxy. The IUCN defines de-extinction as the ecological replacement of an extinct species, adapting a living organism to fill the ecological role of the one that disappeared. A gene-edited mammoth-elephant hybrid won’t be genetically identical to a woolly mammoth. It will be an Asian elephant carrying a set of mammoth traits. The goal is an animal that can do what mammoths did: graze Arctic grasslands, knock down trees, compact snow, and help maintain the tundra ecosystem.
This framing matters because it shifts the question from “can we perfectly resurrect a species?” (no) to “can we engineer an animal that restores a lost ecological function?” (increasingly, yes).
What Could Go Wrong
The risks of releasing engineered species into the wild parallel those of introducing any non-native animal. A proxy species could become invasive, outcompeting or preying on native wildlife. It could hybridize with related species in unintended ways. It could change local ecosystems through overgrazing, altered water flow, or shifts in fire patterns. Perhaps most concerning, it could carry or facilitate the spread of diseases to native species.
Surveys of conservation scientists reflect these worries. Most respondents in risk-assessment studies flagged two primary concerns: that a reintroduced species might fail to establish a self-sustaining population (making the entire effort pointless), and that it might transmit diseases or become invasive, actively harming the ecosystems it was meant to help. These aren’t hypothetical objections. Invasive species are already one of the leading drivers of extinction worldwide, and introducing a genetically novel organism into a wild ecosystem is inherently unpredictable.
The Legal Gray Area
No law was written with gene-edited extinct species in mind. In the United States, recent legal analysis has concluded that genetically engineered wildlife would fall under the Endangered Species Act, giving federal agencies the authority to regulate these animals. That’s a meaningful finding, because it means a mammoth proxy wouldn’t exist in a legal vacuum. Agencies could control where it’s released, how it’s managed, and whether it’s protected or restricted. But the regulatory framework is untested, and the question of whether a gene-edited hybrid “counts” as the species it’s meant to replace will generate debate for years.
Where Things Actually Stand
De-extinction is no longer a question of whether the biology is theoretically possible. The gene-editing tools work. Ancient DNA can be sequenced and its functional elements identified. Cloning from edited cells has been demonstrated in multiple species. The remaining challenges are practical: successfully gestating a mammoth-elephant hybrid to term in a surrogate, keeping it alive and healthy, and eventually building a breeding population large enough to be ecologically meaningful. Each of those steps is hard. None of them violates any known biological law.
The honest summary is this: de-extinction of recently extinct species is scientifically feasible and actively underway. Producing the first living individuals is likely within this decade. But creating self-sustaining wild populations that genuinely restore lost ecosystems is a much longer, harder, and less certain proposition.