Bringing Back the Giants: How Scientists Are Using CRISPR to Resurrect Extinct Species

When Extinction Might Not Be Forever

Imagine standing in the Siberian tundra and watching a herd of shaggy, tusked giants trudging through the snow—animals that look, act, and sound remarkably like woolly mammoths, a species that vanished from Earth over 4,000 years ago. Or picture a pack of large, powerful wolves with distinctive pale coats roaming through a North American preserve, functioning as apex predators just as dire wolves did before they went extinct 12,500 years ago.

This isn't science fiction or wishful thinking. It's the stated goal of Colossal Biosciences, a Dallas-based biotechnology company that has raised over four hundred thirty-five million dollars since 2021 to pursue what they call "de-extinction"—using cutting-edge genetic engineering to bring back species that have disappeared from our planet.

In 2025 and early 2026, Colossal made headlines with two major announcements. First, in March 2025, they revealed the creation of "woolly mice"—laboratory mice genetically engineered with mammoth-like traits including long, shaggy, golden fur. Then, in April 2025, they announced something even more dramatic: the birth of three genetically modified wolf pups designed to mimic the extinct dire wolf, animals they called "the world's first successfully de-extinct animals."

But here's where things get complicated—and fascinating. These aren't actually woolly mammoths or dire wolves in the traditional sense. They're something entirely new: genetically modified versions of living species that have been engineered to express traits from their extinct relatives. The question isn't just whether scientists can do this—clearly, they can. The deeper questions are: should they? And if they succeed, what exactly will they have created?

The Science: How De-Extinction Actually Works

Colossal Biosciences uses CRISPR technology to edit the genomes of living species like Asian elephants and gray wolves, inserting genes from extinct relatives to create proxy animals that mimic key physical and behavioral traits of woolly mammoths and dire wolves.

To understand how this works, you need to know that true resurrection—creating an organism genetically identical to an extinct species—is currently impossible. Ancient DNA degrades over time, leaving scientists with incomplete genetic blueprints full of gaps and damaged sections. You can't simply clone a perfect mammoth from frozen remains like in Jurassic Park.

Instead, Colossal's approach involves several sophisticated steps:

Step 1: Ancient DNA Recovery and Sequencing

Scientists extract DNA from exceptionally well-preserved specimens. For the dire wolf project, they used a thirteen-thousand-year-old tooth found in Ohio and a seventy-two-thousand-year-old ear bone from Idaho. For woolly mammoths, the team has sequenced DNA from specimens ranging from thirty-five hundred to over one million years old.

Using computational biology and artificial intelligence, researchers reconstruct as much of the extinct genome as possible. For dire wolves, they achieved about ninety-one percent genome coverage—impressive, but not complete.

Step 2: Comparing Extinct and Living Relatives

Scientists then compare the extinct genome to that of the closest living relative. Asian elephants share 99.6% of their DNA with woolly mammoths. Gray wolves, while more distantly related to dire wolves than initially thought, still share significant genetic similarity.

This comparison identifies the key genetic differences—the specific genes responsible for distinctive traits like the mammoth's thick fat layer, shaggy hair, small ears adapted for cold, or the dire wolf's larger size and stronger jaw.

Step 3: Gene Editing with CRISPR

Using CRISPR-Cas9 and related gene-editing technologies, scientists modify the DNA of living species to express these extinct traits. For the woolly mice, Colossal edited seven genes simultaneously with remarkably high efficiency—some edits achieving one hundred percent success rates.

For the dire wolf pups, scientists made approximately twenty genetic modifications across fourteen genes in gray wolf embryos. These weren't complete replacements—in many cases, only one copy of each gene was modified, meaning the animals still carry modern wolf versions on their other chromosome.

Step 4: Creating Embryos and Surrogates

The edited cells are used to create embryos through cloning techniques. These embryos are then implanted into surrogate mothers of the living species—gray wolves for the dire wolf project, and eventually Asian or African elephants for the mammoth project.

The three dire wolf pups—males Romulus and Remus born in October 2024, and female Khaleesi born in January 2025—were carried to term by gray wolf surrogates. All three survived and are now growing in a secured preserve.

The Woolly Mammoth Project: Building Cold-Adapted Elephants

The woolly mammoth represents Colossal's most ambitious and well-funded de-extinction target. The company aims to birth the first mammoth-like calf by 2028, though this timeline is highly optimistic given the challenges involved.

In March 2025, Colossal demonstrated significant progress with their "woolly mice." These mice exhibit multiple mammoth-like traits beyond just fur—they also express the mammoth's accelerated fat metabolism, a crucial adaptation that helped mammoths survive ice age conditions. This metabolic difference is key to distinguishing mammoths from their elephant cousins.

The mice serve as proof-of-concept, validating that the genes Colossal identified in mammoth genomes actually produce the intended cold-adapted traits when expressed in living animals. "This was a great step for us to validate that the genes that we were targeting in the woolly mammoth genome are responsible for this specific woolly coat trait," explained Matt James, Colossal's chief animal officer.

Beyond the woolly mice, Colossal has achieved what they call a "global-first" breakthrough: creating induced pluripotent stem cells (iPSCs) from elephant tissue. These are cells that can potentially develop into any type of cell in an elephant's body, which is crucial for creating embryos and eventually testing mammoth traits in cellular models before attempting full pregnancies.

The mammoth project faces unique challenges. Elephants have twenty-two-month gestation periods—nearly four times longer than wolves—and are much larger and more complex organisms. Colossal is developing artificial wombs lined with uterine tissue as an alternative to using live elephant surrogates, which could reduce risks to endangered Asian elephants while enabling more controlled development.

Why Bring Back Extinct Species? The Ecological Argument

The company's ultimate goal extends beyond creating individual animals—they aim to reintroduce these proxies into ecosystems where they could restore environmental balance, such as mammoth-like elephants preventing Arctic permafrost thaw by trampling snow and maintaining frozen ground.

This is where de-extinction moves from fascinating science to potentially world-changing environmental intervention. Colossal's vision isn't creating zoo animals or curiosities—it's ecological restoration on a massive scale.

The Mammoth-Permafrost Connection

Woolly mammoths weren't just passive inhabitants of the Arctic tundra—they actively shaped their environment. Through their feeding behavior, they kept vegetation trimmed and maintained grassland ecosystems. More importantly, their massive weight and constant movement compacted snow during winter.

This might sound trivial, but it has profound climate implications. Compacted snow is less insulating than fluffy snow. When mammoths trampled the snow, cold air reached the ground directly, keeping permafrost frozen even during relatively warm periods.

Today, without these large herbivores, snow accumulates in thick, insulating layers. The ground beneath stays warmer, causing permafrost—permanently frozen ground—to thaw. This thawing releases enormous quantities of trapped methane and carbon dioxide, greenhouse gases that accelerate global warming.

Computer models suggest that reintroducing mammoth-like elephants to Arctic regions could lower ground temperatures by up to eight degrees Celsius in some areas. A recent paper co-authored by Colossal researchers estimated that approximately forty-eight thousand mammoths could survive on Alaska's North Slope, potentially having a material impact on carbon capture and permafrost stabilization.

Apex Predators and Ecosystem Balance

The dire wolf project carries a similar ecological rationale. As apex predators, dire wolves once regulated prey populations, preventing overgrazing and maintaining biodiversity. Their extinction contributed to ecological imbalances that persist today.

The reintroduction of gray wolves to Yellowstone National Park in 1995 demonstrated how powerfully apex predators shape ecosystems. The wolves controlled elk populations, which allowed vegetation to recover. This triggered cascading effects: beaver populations increased, which created wetlands. River erosion patterns changed. The entire ecosystem reorganized around the presence of top predators.

Colossal envisions their dire wolf proxies potentially playing similar roles in carefully managed reserves, though the company has acknowledged that the three current pups will live out their lives in protected confinement rather than being released into wild ecosystems.

Conservation Applications: Helping Species on the Brink

Perhaps the most immediately practical aspect of Colossal's work isn't de-extinction at all—it's using these same technologies to save species currently facing extinction.

Alongside their dire wolf announcement in April 2025, Colossal revealed they had successfully birthed four critically endangered American red wolf pups using identical cloning and gene-editing techniques. With fewer than twenty red wolves remaining in the wild, this achievement could significantly impact conservation efforts.

The company calls this approach "genetic rescue"—using advanced reproductive technologies and genetic engineering to help struggling populations. The techniques developed for extinct species can:

• Increase genetic diversity in small, inbred populations
• Edit out harmful mutations that threaten species survival
• Introduce traits that help species adapt to changing environments
• Enable reproduction when traditional breeding programs fail

Colossal has applied their technologies to conservation efforts for multiple endangered species including the Sumatran rhino in Indonesia, vaquita porpoises in Mexico's Sea of Cortez, the ivory-billed woodpecker in Arkansas, and northern white rhinos in Africa (down to just two females).

"Everything we do is given away to conservation groups for free," says Ben Lamm, Colossal's CEO. "We're subsidizing research and development that no one else is funding."

The Controversy: What Are We Actually Creating?

Despite the technological achievements and ambitious goals, Colossal's work has attracted significant criticism from scientists, ethicists, and conservation biologists. The controversies cluster around several key issues:

Are These Really De-Extinct Animals?

Independent experts have been blunt: these are not actual dire wolves or woolly mammoths. They're genetically modified versions of modern species.

Dr. Beth Shapiro, Colossal's own chief science officer, acknowledged this reality when she stated: "It's not possible to bring something back that is identical to a species that used to be alive. Our animals are gray wolves with twenty edits that are cloned."

The dire wolf pups have just fifteen to twenty dire wolf gene variants out of roughly twenty thousand total genes. Genetically, they're still overwhelmingly gray wolves. Even calling them "hybrids" overstates how much dire wolf DNA they contain.

Paleontologist Dr. Nic Rawlence emphasized that dire wolves and gray wolves diverged between 2.5 and six million years ago—they're quite distant relatives. The handful of genetic changes Colossal made cannot recreate an extinct species that evolved separately for millions of years.

Will They Function Ecologically?

While de-extinction technology offers promising applications for conserving endangered species through genetic rescue, critics argue that these engineered animals are not true resurrections and question whether massive investments in bringing back extinct species serve conservation better than protecting currently threatened wildlife.

Several scientists have questioned whether these proxy animals could ever fulfill meaningful ecological roles. The ecosystems that supported dire wolves and woolly mammoths no longer exist. Climate patterns have changed. Plant and animal communities have reorganized. The prey species that dire wolves once hunted are extinct.

Dr. Jacquelyn Gill, a paleoecologist, noted: "Regardless of what caused the extinction of most of these large grazers, the animals that ate them died because they had nothing to eat."

Even if mammoth-elephants could theoretically affect permafrost, releasing them into Siberia raises practical questions. Who manages these populations? What happens if they can't survive in modern Arctic conditions? What if they have unforeseen negative ecological impacts?

Is This the Best Use of Conservation Resources?

With species going extinct at unprecedented rates and conservation budgets stretched thin, many scientists question whether billions of dollars should fund efforts to bring back extinct species rather than protecting currently endangered ones.

The International Union for Conservation of Nature (IUCN) Red List contains over forty-eight thousand species threatened with extinction. Protecting their habitats, combating poaching, and addressing climate change require enormous resources that are currently lacking.

Critics argue that the same genetic technologies and funding could have vastly greater impact if focused entirely on species conservation rather than splitting attention between saving existing species and resurrecting extinct ones.

Animal Welfare Concerns

The process of creating these animals raises ethical questions about the welfare of both the engineered animals and the surrogates that carry them. Most gene-edited embryos fail to develop. Less than ten percent of the woolly mouse embryos resulted in live births. Similar or worse success rates are expected for larger, more complex animals.

Surrogate mothers may face health risks carrying embryos that differ genetically from normal offspring. The engineered animals themselves might experience unforeseen health problems from their genetic modifications. The dire wolf pups will live their entire lives in confinement in a two-thousand-acre preserve—is this fair to animals engineered to be apex predators?

Student Perspectives: Why This Matters to You

If you're a student reading this, you might wonder why you should care about billionaire-funded attempts to resurrect ice age megafauna. Here's why this technology and the debates surrounding it are relevant to your generation:

You'll Live with the Consequences

Whether de-extinction succeeds or fails, you're the generation that will experience the outcomes. If mammoth-elephants help stabilize Arctic permafrost and slow climate change, you benefit. If these efforts drain resources from conventional conservation and accelerate biodiversity loss, you bear the costs.

It Raises Fundamental Questions

What is a species? If we create animals that look and act like mammoths but aren't genetically identical to historical mammoths, what are they? Who gets to make decisions about recreating extinct life? What responsibilities do we have to animals we create? These questions don't have obvious answers, and your generation will need to grapple with them.

The Technology Has Broader Applications

CRISPR and related gene-editing technologies are transforming medicine, agriculture, and conservation. Understanding how these tools work and their limitations helps you evaluate claims about genetic engineering across many fields—from disease treatment to crop modification to human enhancement.

Career Opportunities

The intersection of synthetic biology, conservation, ecology, genetics, and ethics is creating entirely new career paths. Students interested in biology, environmental science, genetics, bioethics, law, or policy will find that de-extinction technology touches all these fields.

Scientific Literacy Matters

Colossal's work demonstrates how complex evaluating scientific claims can be. The company's announcements generated global headlines, but the reality behind those headlines is far more nuanced. Learning to look past exciting narratives to understand actual capabilities, limitations, and uncertainties is a critical skill in our information-saturated world.

The Road Ahead: What Happens Next?

Colossal's timeline remains ambitious. The company projects birthing the first mammoth-like calf by 2028, though many independent scientists consider this unrealistic. The challenges of elephant reproduction, artificial womb development, and scaling up gene editing to thousands of modifications make this target highly uncertain.

For dire wolves, the company has indicated they might create seven or eight more individuals but has no immediate plans for ecosystem reintroduction. The three existing pups will remain in their protected preserve indefinitely.

Beyond mammoths and dire wolves, Colossal has announced projects to resurrect the dodo bird and Tasmanian tiger (thylacine). The company has also compiled a list of other potential de-extinction candidates including giant ground sloths, saber-toothed cats, Steller's sea cows, and woolly rhinoceroses.

In February 2026, Colossal announced it would create a "biovault" in Dubai's Museum of the Future—a facility storing frozen tissue samples from ten thousand species, including the one hundred most endangered globally. This biobanking initiative acknowledges a sobering reality: despite conservation efforts, many species will likely go extinct, and preserving their genetic material now might enable future restoration.

Playing God or Accepting Responsibility?

The debate about de-extinction often gets framed as humans "playing God"—arrogantly manipulating nature in ways we don't fully understand. But Colossal's leadership frames it differently: as accepting responsibility.

Ben Lamm argues that since humans caused most recent extinctions through hunting, habitat destruction, and climate change, we have a moral obligation to restore what we destroyed—if we have the technological capability to do so.

Both perspectives contain truth. Humans did drive mammoths and dire wolves to extinction, along with countless other species. We are causing an ongoing extinction crisis that threatens to eliminate millions of species over the coming century. If technology could reverse some of this damage, shouldn't we try?

Yet uncertainty about consequences remains. Creating animals that partially resemble extinct species is not the same as restoring lost ecosystems. The resources devoted to bringing back charismatic megafauna might save more biodiversity if redirected to protecting existing species and habitats.

Perhaps the most balanced view recognizes that de-extinction technology and traditional conservation aren't opposing strategies but complementary approaches. The genetic tools developed for resurrecting mammoths can help save elephants, rhinos, and thousands of other threatened species. The publicity generated by ambitious de-extinction projects can raise awareness and funding for broader conservation efforts.

What's clear is that extinction may no longer be forever—but it's also clear that bringing species back is far more complicated than the headlines suggest. These aren't resurrection stories but creation stories, bringing into existence animals that have never existed before: gray wolves with dire wolf traits, Asian elephants with mammoth adaptations.

Whether these novel creatures represent humanity's redemption or hubris, conservation triumph or distraction, won't be known for years or decades. What is known is that the technology exists, the funding is flowing, and the experiments are underway.

For students who will inherit this transformed world, the crucial task is engaging thoughtfully with both the promise and the peril, the science and the ethics, the technical achievements and the deeper questions about humanity's relationship with the natural world and our power to reshape it.

The woolly mammoth may or may not thunder across the tundra again. But the era of genetic engineering reshaping life on Earth has undeniably arrived, and how your generation navigates this power will determine not just which species exist, but what kind of planet we all share.