Because the woolly mammoth and Asian elephant share 99.6% of the same DNA, Colossal aimed to develop a proxy species by swapping enough key mammoth genes into the Asian elephant genome. Colossal's lab pairs CRISPR/Cas9 with other DNA-editing enzymes, such as integrases, recombinases, and deaminases, to splice woolly mammoth genes into the
Asian elephant, and has "used 65 different mammoth genomes across about 700,000 years to create an assembled ancient DNA genome". The company plans on sequencing both elephant and mammoth samples in order to identify key genes in both species to promote population diversification. By doing so, Colossal hopes to prevent any rogue mutations within the hybrid herd. The company plans to use African and Asian elephants as potential surrogates and largely plans to develop artificial elephant wombs lined with uterine tissue as a parallel path to gestation. In 2021, it was reported that Colossal scientists planned on creating these embryos by taking skin cells from Asian elephants and reprogramming them into induced pluripotent stem cells which carry mammoth DNA. Lamm stated that Colossal will use both
induced pluripotent stem cells (iPSC) as well as
somatic cell nuclear transfer in the process. In August 2022, Colossal announced that they would launch a thylacine research project, in hopes of "de-extincting" the Tasmanian tiger. Colossal planned to reintroduce the thylacine proxy to selected areas in Tasmania and broader Australia and claimed that, by doing so, this would re-balance ecosystems that have suffered biodiversity loss and degradation since the species disappeared. A successful thylacine proxy birth could also introduce new marsupial-assisted reproductive technology, which could aid in other marsupial conservation efforts. Colossal partnered with the
University of Melbourne for the project, led by
Andrew Pask. In January 2023, Colossal announced the formation of its Avian Genomics Group, which would be dedicated to reconstructing the DNA of the dodo bird, which went extinct in the 1600s. Led by
Beth Shapiro, who serves as Chief Science Officer to Colossal, Breaking, a
plastic degradation and synthetic biology startup, was developed inside Colossal and launched in April 2024. The startup discovered X-32, a microbe that is capable of breaking down various plastics in as little as 22 months while leaving behind carbon dioxide, water and biomass. It was reported in 2024 that Colossal successfully produced the first-ever elephant and dunnart iPSCs. In October 2024, the company announced that it had rebuilt a 99.9% accurate genome of the thylacine, using a "pickled" 110-year-old fossilized Tasmanian tiger skull. This marks "the most complete ancient genome of any species known to date" and provides a full DNA blueprint to potentially bring back the Tasmanian tiger. Three months later, in January 2025, the company sequenced the complete genome of the Tasmanian tiger; Colossal also made a prototype for an artificial uterus and used that to culture fertilized single-cell
marsupial embryos to over halfway through pregnancy. In March 2025, Colossal announced the creation of gene-edited "
woolly mice" with mutations inspired by woolly mammoths, touting it as a step toward engineering mammoth-like Asian elephants. The mice, which exhibit long, shaggy, tawny-toned fur, were developed using a mix of mammoth-like and known mouse hair-growth mutations. Some experts expressed skepticism, arguing that the experiment was more about mouse genetics than a breakthrough in de-extinction. The company stated that it planned further studies on the mice's cold tolerance and long-term health but had no commercial breeding plans. In April 2025, the
Colossal Biosciences Dire Wolf Project was announced, which used cloning and
gene-editing to birth three genetically modified wolf pups: six-month-old males Romulus and Remus and two-month-old female Khaleesi. In-house scientists analyzed the dire wolf genome, extracted from two ancient samples – a 13,000-year-old tooth and a 72,000-year-old ear bone. After comparing the genomes of
gray wolves and dire wolves to identify the genetic differences responsible for the dire wolf's distinctive features, Colossal isolated
EPC cells from gray wolf blood samples before rewriting 14 key genes in the cell's nucleus to express 20 traits claimed to represent the dire wolf
phenotype. Overall, the work was less invasive than the typical cloning process. Colossal scientists produced 45 engineered
ova, which developed into embryos and inserted into the wombs of two surrogate hound mixes. Colossal claims that these minor genetic modifications effectively revived dire wolves as a species, though "no ancient dire wolf DNA was actually spliced into the gray wolf's genome". The
IUCN Species Survival Commission Canid Specialist Group officially declared that the three animals are neither dire wolves nor proxies of the dire wolves based on the IUCN SSC guiding principles on creating proxies of extinct species for conservation benefit. They commented that creating phenotypic proxies doesn't change the conservation status of an extinct species and may instead threaten the extant species such as grey wolves. Therefore, since the claimed proxies do not conform with the IUCN SSC guidelines, have no ecological niche left today and "will not restore ecosystem function", they concluded that the Colossal Biosciences' project "does not contribute to conservation." Colossal Biosciences released a clarifying document
Alignment of Colossal’s Dire Wolf De-Extinction Project with IUCN SSC Guiding Principles in response. In May 2025, the company's chief scientist
Beth Shapiro stated that the three animals are merely "grey wolves with 20 edits" as purportedly stated by the company "from the very beginning", acknowledging that it is impossible to bring back an extinct organism, or at least an organism "identical to a species that used to be alive". She admitted that the term "dire wolves" applied to the pups are a
colloquialism, not
scientific terminology. This is a "major departure from what Colossal had said previously". In the same month, Colossal along with
University of Melbourne announced that they have successfully created vital stem cells for the thylacine, with researchers estimating they could be re-introduced in the wilderness as little as 8 years.
Future projects Outside of their first five projects, Colossal Biosciences has stated that they have a "long list" of species that they want to revive and reintroduce to appropriate ecosystems. Such species include
Castoroides,
Arctodus, and
Steller's sea cow. Ben Lamm has stated that he and his company want to revive Steller's sea cow once they have developed an
artificial womb, as there are no adequate living relatives of the extinct sea cow to act a surrogate species. Colossal has also done genetic research for the following species;
Irish elk,
great auk,
bluebuck,
ground sloths,
saber-tooth cats,
long-horned bison,
Columbian mammoth,
cave hyena,
mastodons,
American cheetahs,
tooth-billed pigeons, and
woolly rhinoceros, with the intent to potentially revive them in the future. Colossal is the first company to apply CRISPR technology to species restoration efforts.
University of Otago zoologist Philip Seddon said the project had "nothing much to do with solving the global extinction crisis and more to do with generating fundraising media coverage". Colossal rejected this characterization. He called for greater transparency from the parties involved about how widely they had engaged with
Ngāi Tahu. ==Conservation==