A giant bear from the Ice Age and a 5ft-tall beaver could be next in line for resurrection by de-extinction scientists.
At Colossal Biosciences in the US, scientists are already well on their way to reviving the mammoth, Tasmanian tiger (thylacine) and the dodo – but they have other creatures in their sights too.
Prof Beth Shapiro, chief science officer at Colossal, said she had a “very long list” of extinct animals she would like to see brought back.
“I would like to work on all of them because I’d like to learn more about the biology of these animals,” she told The Telegraph. “Carnivores would be cool.
“One of my favourite extinct species is a thing called Arctodus, the giant short-faced bear, which stood 14ft tall, and giant beaver that lived in North America, which would have stood up to be about 5ft tall. That would be funny.”
Arctodus lived in North America during the Pleistocene, from around 2.5 million years ago until it became extinct around 11,000 years ago.
It is thought to be the largest land-dwelling species that ever existed on the continent, standing as tall as a human male when walking on four legs. They went extinct because of the fall in large herbivores to hunt, as well as competition from humans and brown bears, experts believe.
The giant beaver, castoroides, was an enormous rodent which also lived in North America during the Pleistocene and became extinct about 10,000 years ago. Recovered skulls suggest it could swim underwater for large periods, and had six-inch teeth.
Although bringing back animals from extinction has echoes of Jurassic Park, the team at Colossal hopes the techniques they are pioneering could uncover lost genetic traits from the past and ensure that no species alive today need ever go permanently extinct.
Earlier this year the team announced it had successfully created pluripotent stem cells from Asian elephant skin cells, a significant breakthrough which could help create elephant sperm and egg cells, and ensure the survival of the species.
It could also help bring back the mammoth. Mammoths share 99.5 per cent of their genes with Asian elephants, meaning gaps in mammoth DNA will be filled in with the genetic material from modern elephants, and Colossal will be using the new stem cell lines to test the genetic tweaks.
Likewise, the team has been collecting primordial germ cells (PGCs) from Nicobar pigeons for use in bringing back the dodo. The pigeon, which lives in the Andaman and Nicobar Islands in India, is the dodo’s closest living relative.
“Every time I go into the lab, I’m shocked at the progress that’s being made,” Prof Shapiro said.
“The Thylacine team have been able to make cell lines that have more unique edits to the genome than anyone has ever been able to make.
“And the primordial germ cells work for the pigeons – that is progressing at a rate that is faster than what I expected. So that’s very exciting and encouraging.
“It has applications across the board in human health and biodiversity and working to combat the extinction crisis.
“Sure, it’s cool to think of bringing extinct species back, with the understanding that they’re not going to be identical copies of these extinct species. In the next decade, I would have liked to have achieved several successful de-extinctions.
“But the real benefit of these technologies is to have them at our fingertips, to be able to use as one of our approaches to biodiversity conservation.”
‘Ultimate goal to make extinction thing of the past’
The company has been focusing on endangered animals such as the vaquita, a porpoise which is also one of the most threatened marine species on the planet, the northern white rhino, which is on the brink of extinction, and the pink pigeon, a rare species found in Mauritius.
Saving a species can also keep ecosystems healthy.
She added: “You can imagine a species that’s very recently extinct, that the habitat is sort of teetering at the edge because that extinction has made some really important components of that ecosystem disappear.
“So everything is sort of out of sync, and if you could create or re-engineer some of those ecological interactions in some way that could actually have a cascading impact on that entire habitat.
“Obviously, the ultimate goal of Colossal is to make extinction a thing of the past.”
The team is now delving far deeper into the past, hunting for ancient DNA which could lead to the discovery of entirely new species never found in the fossil record.
In recent years, experts have found fragments of DNA that date back two million years in Greenland, and it is possible that samples could be preserved from even further back in time.
However, Prof Shapiro said she would draw the line at ancient hominids and human ancestors, such as Neanderthals.
“Hominids like Neanderthals and Denisovans, they were people, right? And they would need some sort of informed consent,” she said.
“In this case, I don’t think you could ask their permission. So probably that’s where I would draw the line.”
Colossal was founded in 2021 by Harvard geneticist George Church and entrepreneur Ben Lamm.
Prof Shapiro was talking ahead of the UK Imax release of Hunt for the Oldest DNA and the launch of The Colossal Foundation, a new non-profit organisation which aims to save, sustain and increase endangered animal populations.
