Remus and Romulus

Colossal Biosciences (wolves); Shutterstock.com (background)

Should We Bring Back Extinct Animals?

September 15, 2025

By Cailin Loesch

As You Read, Think About: Would bringing back extinct creatures help other animals or hurt them?

Animals of the Ice Age

Watch a video to learn more about extinct animals.

Colossal Biosciences

Khaleesi

Long ago, dire wolves roamed what is now North America. During the last ice age, these powerful animals used their strong jaws and huge teeth to feast on young woolly mammoths and other creatures. The fearsome predators became extinct more than 10,000 years ago. But earlier this year, a company called Colossal Biosciences announced that it had brought back the extinct wolves—sort of.

Two male pups, Remus and Romulus (above), were born last October. They were joined by a female pup, Khaleesi (right), in January. To bring the pups to life, scientists at Colossal changed the DNA of modern-day gray wolves. (DNA is the material in cells that determines how living things look and function.) Though the new animals look similar to dire wolves, they are not exact copies of the extinct creatures.

Colossal plans to use a similar “de-extinction” process to create new versions of other extinct animals, including the woolly mammoth, Tasmanian tiger, and dodo bird.

Some people think bringing back animals of the past would be exciting—and good for their former habitats. But others worry that it may do more harm than good.

Long ago, dire wolves lived in what is now North America. During the last ice age, these powerful animals ate young woolly mammoths and other creatures. They had strong jaws and huge teeth. The predators became extinct more than 10,000 years ago. But earlier this year, a company called Colossal Biosciences made an announcement. It said it had brought back the extinct wolves—sort of.

Two male pups were born last October. They’re named Remus and Romulus (above). In January, they were joined by a female pup named Khaleesi (right). To bring them to life, scientists at Colossal changed the DNA of modern-day gray wolves. (DNA is a material in cells. It determines how living things look and function.) The new animals look similar to dire wolves. But they are not exact copies of the extinct creatures.

Colossal plans to use a similar “de-extinction” process to create new versions of other extinct animals. These include the woolly mammoth, Tasmanian tiger, and dodo bird.

Some people think bringing back extinct animals would be exciting—and good for their former habitats. But others worry that it may do more harm than good.

Is de-extinction a good idea?

Scientists from Colossal think de-extinction could one day be a big victory for conservation.

“When species go extinct, they leave holes in ecosystems,” explains Beth Shapiro, a chief scientist at Colossal. “We have the ability to fill those holes.”

Take woolly mammoths, for example. These huge beasts were relatives of modern elephants. Mammoths were once a keystone species in the Arctic, meaning they affected everything in their ecosystem. Scientists at Colossal say bringing mammoths back could benefit the plants and animals that live in the Arctic today.

Shapiro says Colossal wouldn’t release a new animal into the wild without first spending years studying how it might affect its environment.

Plus, Shapiro argues that de-extinction technology could also help species that are currently endangered. It might be used to change the DNA of animals to make them stronger and better able to fight diseases.

“As we develop these tools, we will be able to use them to protect species that are alive from becoming extinct in the first place,” she says.

Scientists from Colossal think de-extinction could one day help conservation.

“When species go extinct, they leave holes in ecosystems,” explains Beth Shapiro. She’s a chief scientist at Colossal. “We have the ability to fill those holes.”

Take woolly mammoths, for example. These huge beasts were related to modern elephants. Mammoths were a keystone species in the Arctic. That meant they affected everything in their ecosystem. Bringing mammoths back could benefit the plants and animals living in the Arctic today. That’s according to scientists at Colossal.

Shapiro says Colossal wouldn’t release a new animal into the wild without studying how it might affect its environment.

Plus, Shapiro argues that de-extinction technology could help today’s endangered species. It might be used to change the DNA of animals to make them stronger.

“As we develop these tools, we will be able to use them to protect species that are alive from becoming extinct in the first place,” she says.

More than 47,000 species are in danger of dying out.

^{Source: International Union for Conservation of Nature}

Many scientists point out that Colossal didn’t really bring back dire wolves. Instead, it made a new version of the gray wolf. Some say creating these animals is a cruel experiment. They worry that the new animals may face constant testing and suffer from health problems.

Others think de-extinction could harm the environment, not help it. They argue that, even with careful planning, it’s hard to predict how a new species would behave and interact with other animals.

People who oppose de-extinction say it costs too much money. Since 2021, Colossal has raised more than $435 million for de-extinction efforts. Many say that money would be better spent on trying to save endangered animals.

“Some people might think we don’t need to worry about dying species because we can just bring them back one day,” says Jerry Coyne. He’s a retired professor at the University of Chicago. “And that’s wrong.”

Many scientists say that Colossal didn’t really bring back dire wolves. Instead, it made a new version of the gray wolf. Some say it’s cruel to create these animals. The new animals may face constant testing. They could suffer from health problems.

Others say de-extinction could harm the environment, not help it. Even with careful planning, it would be hard to predict how a new species would interact with other animals.

People against de-extinction say it costs too much money. Since 2021, Colossal has raised more than $435 million for de-extinction efforts. Many say it would be better to spend that money trying to save endangered animals.