San Diego Zoo tries to bring rhinos back from the brink

Geneticists from the San Diego Zoo Institute for Conservation Research are taking the initial steps in bringing the Northern white rhino back from the brink. Using cryopreserved cells and the support of the Seaver Institute they hope to create a northern white rhino from preserved cell.

They have 12 Northern white rhino lineages to work with. These were stored in the Frozen Zoo® at the San Diego Zoo. Currently they are hoping to use new technologies so they can gather the genetic knowledge needed to create a viable population of this species.


“Multiple steps must be accomplished to reach the goal of establishing a viable population that can be reintroduced into the species range in Africa, where it is now extinct,” explained Oliver Ryder Ph.D., Director of Genetics for the San Diego Zoo Institute for Conservation Research. “A first step involves sequencing the genomes of northern white rhinos to clarify the extent of genetic divergence from their closest relative, the southern white rhino.”

After this process is complete they would need to convert some of the cells stored in the Frozen Zoo® to stem cells. These could then be developed into sperm and egg. Dr. Jeanne Loring of the Scripps Research Institute figured out this process in 2011.

“If we can take reprogrammed cells and direct them to become eggs and sperm, we can use in vitro fertilization to generate a new animal,” she explained. “Bold new initiatives are required to save endangered species, and we recognize the application of stem cell technology using cells in the Frozen Zoo® provides hope for preventing extinctions, with scientific innovation helping to lead these efforts.”


At the Safari Park researchers have worked for decades to breed Northern white rhinos but weren’t successful as they only had four aged individuals to work with. Barbara Durrant Ph.D, a reproductive physiologist at the San Diego Zoo Institute for Conservation Research also explained that “The reproductive system of rhinos is very complex and there is still so much we do not know,” providing another challenge.

“We will meet the challenge to save this beautiful animal by combining recent advances in genetic and reproductive technology with our expertise in animal care and welfare,” added Durrant.

Northern White rhinos are on the brink of extinction. None are left in the wild and only one is left at the San Diego Zoo Safari Park. Three more live in Kenya at the Ol Pejeta Conservancy and the last one is at Dvur Kralove Zoo in the Czech Republic. These last five rhinos are in their twilight years and have never reproduced.


The zoo recently received a $110,000 grant from the Seaver Institute to fund sequencing the northern and southern white rhino genomes. This will allow them to determine if assisted reproduction mechanisms may be helpful for future breeding.

Victoria Dean, President for the Seaver Institute said, “The Seaver Institute supports fundamental research and innovative inquiry for particular projects that offer the potential for significant advancement in their fields. “We are interested in supporting this proect which will take advantage of the, until now, theoretical value of the Frozen Zoo.”

Photo Credits: San Diego Zoo Global

By Cale Russell is a testament to Cale’s commitment to the education of people around the world on the topic of animals and conservation, through the sharing of topical and newsworthy information.

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