Modern-Day Mammoths?

Seeing a herd of mammoths roaming close to a town today would be a surprising sight. That’s because the massive animals haven’t existed on Earth for about 10,000 years! Mammoths lived during the ice age when sheets of ice covered most of what is now Europe, Asia, and North America. Beyond this frozen expanse stretched the tundra, a dry and cold region of grasslands that bison, horses, reindeer, and mammoths called home. Even though mammoths haven’t roamed the tundra for thousands of years, a U.S.-based company wants to “de-extinct,” or bring back, the animals and reintroduce them into the wild.

Colossal Biosciences plans to create a hybrid animal—a combination of a woolly mammoth and its closest living relative, the Asian elephant. Reviving the mammoth would provide a glimpse of a real-life prehistoric creature, says Ben Lamm, the co-founder of Colossal. “People have a childlike wonder to see what used to be here,” he says. Lamm believes that bringing back mammoths and other extinct animals could also benefit the planet (see Making a Comeback). He thinks their return may improve the health of their former ecosystems—communities of organisms interacting with their nonliving environments.

But some scientists aren’t so sure the company’s efforts will be successful—or if they should even try creating a mammoth hybrid. Critics say it’s hard to know if these animals would be able to survive in our modern world and whether they could cause more harm than good.

Earth looked very different 22,000 years ago. The last ice age was at its peak. Sheets of ice covered most of what is now Europe, Asia, and North America. Beyond the vast ice sheets, the tundra stretched out. It was a dry and cold region of grasslands. Bison, horses, reindeer, and woolly mammoths roamed it.

Mammoths looked similar to modern-day elephants. But they had long, curved tusks and a thick coat of shaggy hair. The environment got warmer, and early humans overhunted mammoths. So the animals died out about 10,000 years ago. Now a U.S.-based company wants to “de-extinct” mammoths. The company hopes to bring them back and return them to the wild.

Colossal Biosciences plans to create a hybrid animal. It would be part woolly mammoth and part Asian elephant. That’s the mammoth’s closest living relative. If the mammoth returns, people could see a real-life prehistoric creature, says Ben Lamm. He’s the cofounder of Colossal. “People have a childlike wonder to see what used to be here,” he says. And Lamm believes the planet could benefit from the return of mammoths and other extinct animals (see Making a Comeback). He thinks the animals may improve the health of their former ecosystems. These are communities of organisms in their environments.

But some scientists aren’t so sure the company will succeed. And they don’t know if a hybrid mammoth is a good idea. Critics say it’s hard to know what would happen. Could these animals survive in our modern world? And would they cause more harm than good?

Woolly mammoths towered up to 3.7 meters (12 feet) tall and weighed up to 8 tons. Because of their enormous size, they had a big impact on the tundra’s landscape. The herbivores trampled shrubs and trees and dug up the ground with their tusks while searching for plants to eat. Their poop fertilized the soil. This helped ancient grasslands grow. Today in the tundra, “a lot of that same plant life still exists,” says Lamm, “but its ecosystems aren’t thriving as they used to.” And moss, shrubs, and trees have replaced some grasslands.

The tundra has changed in other ways as well. Beneath the ground’s surface lies permafrost, a layer of soil that remains permanently frozen. In recent years, warming temperatures brought on by climate change have led permafrost to thaw. As a result, huge amounts of greenhouse gases once locked in the icy ground are now being released. These gases trap heat in Earth’s atmosphere, further contributing to climate change.

Colossal hopes that returning mammoths to the tundra will again promote the growth of grasslands. Grasses absorb less sunlight than trees, keeping the ground cooler and helping to maintain permafrost. The animals would also disturb snow cover, which normally prevents cold air from reaching the ground. This would help keep the soil frozen. But there’s a lot to do before a mammoth-like creature can be reintroduced.

Woolly mammoths stood up to 3.7 meters (12 feet) tall and weighed up to 8 tons. The huge animals had a big impact on the tundra’s landscape. As these herbivores searched for plants to eat, they trampled shrubs and trees. They also dug up the ground with their tusks. Their poop fertilized the soil. This helped ancient grasslands grow. Today in the tundra, “a lot of that same plant life still exists,” says Lamm, “but its ecosystems aren’t thriving as they used to.” And moss, shrubs, and trees have replaced some grasslands.

The tundra has also changed in other ways. Permafrost lies beneath the ground’s surface. This is soil that remains permanently frozen. In recent years, climate change has brought warmer temperatures. This has caused soil that used to be permafrost to thaw. Huge amounts of greenhouse gases were locked in the icy ground. But now they’re being released. These gases trap heat in Earth’s atmosphere and add to climate change.

Colossal plans to return mammoths to the tundra. The company hopes that this will help grasslands grow again. Grasses absorb less sunlight than trees. So they keep the ground cooler and help to maintain permafrost. And normally, snow prevents cold air from reaching the ground. Mammoths would disturb snow cover, and this would help keep the soil frozen. But a lot must happen before a mammoth-like creature can return.

Colossal’s scientists plan to create a hybrid mammoth by altering an Asian elephant’s DNA—the molecule that carries hereditary information. They’ll use a technology called CRISPR to insert 65 mammoth genes. These units of hereditary material code for traits that allowed mammoths to survive on the frozen tundra. The traits include a shaggy coat of hair and a thick layer of fat. Scientists identified the genes by studying DNA from preserved mammoth remains. “We want to see these animals in the wild thriving and being able to completely sustain themselves,” says Eriona Hysolli, a geneticist who heads the team creating Colossal’s hybrid mammoth.

Scientists then plan to harvest eggs, or female reproductive cells, from Asian elephants—something that’s never been done. Next, they’ll insert the edited DNA into one of the eggs to create an embryo—the earliest stage of an organism’s development (see Creating a Mammoth). Hysolli’s team will then implant the embryo into the womb of a female Asian elephant, where it will gestate, or develop into a baby mammoth.

In the next phase of the study, Hysolli’s team will try gestating the embryo inside a saclike device filled with fluid. It will serve as an artificial womb. Other scientists have already begun experimenting with this technology, but none have successfully gestated a baby animal. “This type of technology has not yet been used successfully,” says Matthew Cobb, a zoologist at the University of Manchester in the United Kingdom who isn’t involved with the project.

Colossal’s scientists have a plan to create a hybrid mammoth. First, they’ll alter an Asian elephant’s DNA. This molecule carries hereditary information. They’ll use a technology called CRISPR to insert 65 mammoth genes. These units of hereditary material code for certain traits. They include a shaggy coat of hair and a thick layer of fat. These traits allowed mammoths to survive on the frozen tundra. Scientists identified the genes in DNA from preserved mammoth remains. “We want to see these animals in the wild thriving and being able to completely sustain themselves,” says geneticist Eriona Hysolli. She heads the team creating Colossal’s hybrid mammoth.

Then scientists plan to remove female reproductive cells, called eggs, from Asian elephants. That’s never been done. Next, they’ll insert the altered DNA into one of the eggs. This will create an embryo. It’s the earliest stage of an organism’s development (see Creating a Mammoth). Hysolli’s team will implant the embryo into the womb of a female Asian elephant. There, the embryo will gestate. It will develop into a baby mammoth. 

In the next part of the study, Hysolli’s team will test using an artificial womb. This saclike device is filled with fluid. They’ll try to gestate an embryo inside it. Other scientists are already trying this technology, but none have succeeded. “This type of technology has not yet been used successfully,” says Matthew Cobb. He's a zoologist at the University of Manchester in the United Kingdom, and he isn’t involved with the project.

Even if Colossal can create a living, breathing mammoth-elephant hybrid, Cobb worries about the animal’s welfare. Because a mammoth calf will look different from a typical elephant, its mother may reject it. And a hybrid grown in an artificial womb would have no birth mother at all. Mother elephants teach their children important behaviors, like how to interact with other members of their species and find food. Cobb wonders if a hybrid mammoth would be able to survive in the wild without this nurturing.

Cobb is also concerned about how the hybrid mammoths would interact with modern surroundings and problems they could create. He cites examples of Asian elephants in India that trample and raid farmlands for food. Additionally, Cobb says Asian elephants are often struck by cars as they attempt to cross roads.

No one knows for certain what might happen to the tundra if mammoths were brought back in. “We have very little idea how they might affect the ecosystem,” says Cobb. Mammoths’ ability to alter the tundra to protect against future climate change is just as uncertain. Cobb suspects any impact would be minimal. “I don’t think they could make it worse, but I don’t think there will be a measurable effect,” he says.

Colossal estimates that a mammoth hybrid won’t be created until at least 2027 or released into the tundra until at least 2033. In the meantime, Lamm says, the company is collaborating with wildlife groups and Native peoples to carefully consider any issues that could arise from the animals’ reintroduction. Colossal’s wild plan to bring back the mammoth won’t be easy. It will take a large team of scientists equipped with cutting-edge techniques to succeed. But if scientists do manage to bring back an extinct prehistoric creature, who knows what other ancient animals they might bring back next?

Even if Colossal succeeds, Cobb worries about the welfare of a living mammoth-elephant hybrid. A mammoth calf will look different from a typical elephant. So its mother may reject it. If a hybrid grows in an artificial womb, it won’t have a birth mother. Mother elephants teach their children important behaviors. For example, they show them how to interact with other elephants and find food. Cobb wonders if a hybrid mammoth could survive in the wild without this training.

Cobb has other concerns. How would hybrid mammoths interact with modern surroundings? What problems could they create? He gives examples of Asian elephants in India. Some trample and raid farmlands for food. And cars often strike Asian elephants as they cross roads, he says.

What might happen to the tundra if mammoths return? No one knows for certain. “We have very little idea how they might affect the ecosystem,” says Cobb. And no one knows if mammoths could alter the tundra to protect against future climate change. Cobb thinks any impact would be small. “I don’t think they could make it worse, but I don’t think there will be a measurable effect,” he says.

Colossal says that a hybrid mammoth won’t be created until at least 2027. And it won’t be released into the tundra until at least 2033. In the meantime, the company is working with wildlife groups and Native peoples, Lamm says. They’re carefully considering any issues that the animal’s return could cause. Colossal’s wild plan to bring back the mammoth won’t be easy. It will take a large team of dedicated scientists. And they’ll need cutting-edge technology to succeed. But if scientists do bring back an extinct prehistoric creature, who knows what other ancient animals might be next?