Backed by Peter Jackson and Māori leaders, a U.S. biotech firm plans to revive the colossal South Island moa – the largest bird that ever lived – within eight years, writes Patrick Drennan.
SCIENTISTS PLAN to bring back the world's largest extinct bird within eight years.
The South Island giant moa, the largest bird that ever existed – even bigger than the famous dodo – went extinct about 600 years ago, with the arrival of the first humans to the islands of New Zealand.
The giant moa was 3.6 metres in height with its neck outstretched, weighing about 230 kilograms.
Living in the pristine South Island, it evolved to a great size because of dense vegetative food sources and because it had only one known predator – appropriately, the world’s largest eagle – the Haast’s eagle.
The first humans, the Polynesian islanders who became known as the Māori, devoured the nine species of Moa within 200 years of arriving.
On 8 July 2025, U.S. company Colossal Biosciences announced a $US50 million (AU$77.3 million) project to revive the flightless bird through gene editing and surrogate hatching. Backers include the Māori Ngāi Tahu tribe and billionaire filmmaker Peter Jackson.
Jackson also backed another Colossal project, bringing the dire wolf back to life after 10,000 years. Because of their intensive work on the Dodo Restoration Project, Colossal anticipate that they will be able to complete a moa restoration within eight years.
Colossal will harness the genes from moa bones and match them with the genome of the moa’s closest living relatives, which include the South American great tinamou, and distant ratite cousins like the Australian emu. They will then insert the resulting DNA into the egg cells of the host bird.
The resulting egg could measure about 240 millimetres long. A great tinamou egg is about 60 millimetres long, and an emu egg is about 152 millimetres long.
The research has raised intense academic debate.
The International Union for Conservation of Nature (IUCN) suggests that attempting to “bring back” an extinct species using a proxy species creates a hybrid, which is not considered a pure species in their assessment.
Professor Emeritus Philip Seddon, Department of Zoology, University of Otago, stated:
“Extinction really is forever. There is no current genetic engineering pathway that can truly restore a lost species, especially one missing from its ecological and evolutionary context for hundreds of years.”
Professor Tammy Steeves, School of Biological Sciences, University of Canterbury, stated:
Beyond the ethical, legal, political and economic issues raised by using de-extinction technologies in conservation, the scientific challenges are immense.
For example, to de-extinct the dire wolf, the team at Colossal focused exclusively on morphological traits controlled by a few genes of large effect. In other words, they targeted ‘big impact’ genes, none of which are related to improving traits associated with reproduction and survival.
Recovering small, inbred populations would require targeting multiple traits associated with reproduction and survival, most of which are likely to be controlled by many genes, each of small effect. Such ‘small impact’ genes are notoriously hard to find, especially in endangered species.
Nevertheless, many non-academic observers, raised on the Jurassic Park film series, are fascinated by the prospect. This raises several thought-provoking questions.
Will the recreated moa be fully a moa?
Traditional thought says that an attempt to recreate a moa using DNA from a related species to fill in gaps in the moa genome would result in a hybrid rather than a true moa. Yet, according to Colossal Biosciences, their “de-extinction project” aims to recreate a moa that is as close to the original as possible, with no genetic material from other species. This means the resulting animal should be genetically identical, or very close to it.
Does this mean that woolly mammoths and dinosaurs can also be re-established?
Firstly, their DNA is very old and currently unusable. Secondly, their extinction was caused by environmental reasons — the atmosphere and plants on which they thrived have changed dramatically.
While the rainforests of New Zealand are less dense than 600 years ago and the climate is slightly warmer, the conditions and plants the giant moa would need to survive are still in place.
Where will these giant moas live?
New Zealand has several significant mainland bird sanctuaries, surrounded by predator-proof fences. They protect some of the world’s rarest birds, including the kiwi, the takahē, and a huge pigeon, the kererū — a strange bird that gets drunk by gorging on summer berries and falls out of trees. In the wild, introduced pests like possums, rats, stoats and feral cats prey on these birds and their eggs, or eat the plants and seeds these creatures need to survive.
The South Island has two mainland bird sanctuaries that could house a giant moa — Orokanui Ecosanctuary in Otago and the Brook Waimārama Sanctuary in Nelson. Whether their deep-dug, predator-free fences would contain a giant moa is another matter. There is also the offshore Ulva Island, over 30 kilometres from the mainland.
Will they attack humans?
Like their ratite cousins, the emu, the male moa incubates the eggs. They might defend their eggs if threatened, but there is no oral traditional record from ancient Māori of moa attacking humans.
The advantages of reestablishing the moa
Ecotourism will boom in New Zealand.
It is likely to advance science in a significant manner. The gene editing techniques used to revive the giant moa will help protect many vulnerable bird species worldwide. Furthermore, it may be one of the techniques used to cure some human cancers. More specifically, it will help reverse the immense damage done to the natural environment by humans.
Many conservationists say that the money would be better spent on the environment and other species.
When questioned on this matter, Peter Jackson poignantly replied:
“Why don’t we do both?”
Patrick Drennan is a journalist based in New Zealand, with a degree in American history and economics.
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Australia License
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