Frozen in time: The science and ethics of saving species

Recently, San Diego Zoo Global (SDZG) held a small conference entitled “Expanding the Discussion: The ethical and social issues surrounding the northern white rhino genetic rescue initiative.” We discussed the collaborative efforts focused on rescuing the northern white rhinoceros from extinction. This is a natural extension of our mission to lead the fight against extinction. 

We recognize that we are stewards of wildlife, focusing on animal care and welfare, while seeking to foster societal change that benefits the future of the diversity of species and the ecosystems that sustain them on this planet. Notable experts and influential thinkers convened to consider issues involved in responding to the otherwise inevitable loss of the northern white rhino, and, as the title of our meeting implies, expand the discussion. 

Global concern for the future of species, as evidenced by recent reports from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Servicesand reportsin scientific journalspredicting declines in biodiversity – in spite of all conservation efforts now being undertaken – poses the challenge of a lifetime to those of us who have engaged in efforts to prevent extinctions and recover species. It’s clear that new and unprecedented efforts need to be explored. The outcomes of our conservation strategies, actions and inactions, will affect humans for generations – many generations – into the future. 

The case of the northern white rhinoceros

It would be fair to say that Nola, the beloved female northern white rhino who lived to a ripe old age and ended her days at the San Diego Zoo Safari Park, played a role in fostering the recent conference. Nola has become an icon for the extinction of her kind and a symbol of hope, ironically. 

Representing a unique form rhinoceros, Nola was seen by millions of visitors who heard her story, and that of her intended mate, Angelifu. Nola was living proof of the plight the remaining northern white rhinos faced, after surviving civil war and rampant poaching that brought down the wild population. 

In 1992, when Nola was 18 years old, a skin biopsy was obtained. The skilled cell culturists of the Biodiversity Banking team that looks after the Frozen Zoo® established and preserved these living cells of Nola, storing them securely at a frigid -273°F. 

In the 1970s, Nola was removed from her family in Africa, transported to Czechoslovakia, then to California, becoming the last of her kind in the Western Hemisphere. Nola’s cryopreserved cells survive in a frozen state with those of eleven other northern white rhinos in the Frozen Zoo. While she never had a calf, her cells are incredibly valuable to her kind’s genetic diversity. 

It is in these frozen cells that the hope for the future of the northern white rhino is embodied, through the intention of scientific progress in stem cell biology, genomics, and assisted reproductive technologies. Researchers hope to have the frozen cells of Nola and the others produce baby rhinos, with southern white rhinos carrying northern white rhino embryos to term. 

This hope led to the northern white rhino genetic rescue initiative, the inherent concept of which is staggering, and the implications unprecedented.

Looking forward

We realized early on that we would be called upon to advance and develop a vastly more sophisticated knowledge of the cellular biology of embryonic development of the white rhinoceros, its genetics, and its reproduction. We have discussed the implications of both undertaking this work, and the successes and failures we might have. Our efforts could impact and even re-structure fundamental concepts of species conservation and the impacts of human actions on the evolution of life on our planet. 

We have responded to the extinction crisis for the northern white rhino with a hopeful, albeit complex, initiative. It rightfully brings up other stirring questions: Will there be other species that face a similar plight and should we contribute to efforts to bring these species back from the brink of extinction? If so, have cells from a sufficient number of individuals been preserved? And perhaps most importantly: Will efforts to save species be considered less urgent if it is thought that having viable cells frozen can bring back extinct species?

These and other questions arose at the conference, but the purpose was not so much to answer those questions as to bring them into the light. 

Considering the application of new technologies and methods requires careful and appropriate reflection. As we make progress on the northern white rhino genetic rescue initiative, we foresee that discussions of new conservation strategies, which may be led by emerging technologies, will arise and likely become a part of the landscape of the conservation intervention decision process.  

As we enter into new, uncharted territory with scientific applications to conservation, we also enter new realms of social and ethical issues. Our small conference was a first step toward a precedent for future discussions that will contribute to the careful consideration of the far reaching impacts of scientific advances toward ending extinction.