Each day 96 elephants lose their lives at the hands of poachers. This is not an exaggeration but rather a well-documented fact. The illegal trade of ivory is the biggest cause of elephant hunting. Despite efforts over the past decades to stop the poaching of these animals for their tusks, the ivory trade is still very much alive around the world. In fact, the United States remains among one of the world’s largest consumers of ivory in spite of Congress passing the African Elephant Conservation Act in 1989, nearly 30 years ago.
In the early 20th century, there were an estimated 5 million elephants in the wild. By 1980, however, the number of elephants was down to only 1.2 million and the population has continued to decline rapidly. In fact, since 1989 when official global records begin to be kept, the highest volume of illegal ivory seized occurred in 2011. And, today experts estimate that the wild population is now at approximately 350,000 elephants in Africa. Based on simple calculations, at the rate that elephants are being killed each day these animals will be extinct in the wild within 8 to 10 years. Elephants, however, are not the only species of animals hunted by humans to satisfy a desire for prestige. Other wildlife has been brought to extinction or to the brink of extinction in order to fulfill societal desires for status symbols of wealth and success. For instance, there were approximately 500,000 rhinoceroses across Africa and Asia at the beginning of the 20th century. Yet, although the adult rhinoceros has no predators in the wild except for humans, this number fell to 70,000 by 1970 and to just about 29,000 in the wild today.
Similar to what is happening with elephants, rhinoceroses are hunted and killed by humans for one body part – their horns – even though the horn of a rhinoceros is made of up primarily of keratin, a protein found in human hair and fingernails, and animal hooves. The major demand for rhinoceros horn use is for ornamental carvings like an elephant ivory tusk. The horn is also used though for what is considered traditional medicine, as cures for various conditions ranging from hangovers to cancer and impotence. To say that 29,000 rhinoceroses remain in the wild today, however, is misleading as certain species and subspecies are extinct already or on the verge of disappearing completely. For instance, there are less than 100 remaining Sumatran and less than 60 Javan rhinos left in the world. And, with the death of the San Diego Zoo’s beloved Nola on November 22, 2015, and the death of Sudan on March 19, 2018, the only remaining male of his species, there are now only two Northern white rhinos left, Najin and Fatu. Najin, a female born in captivity in 1989, is the daughter of Sudan, and Fatu, Najin’s daughter, also born in captivity in 2000, is Sudan’s granddaughter.
These two remaining Northern white rhinos belong to the Dvůr Králové Zoo in the Czech Republic. They were transported to the Ol Pejeta Conservancy in Kenya, Africa in 2009 for safe keeping and in a last-ditch effort to save the critically endangered subspecies. At that point in time there were eight Northern white rhinos remaining in the world, but no offsprings have resulted from any of these conservation efforts. Under 24-hour armed guard supervision, Najin and Fatu are the last of their species. No other Northern white rhinos are known to exist in the wild or in managed care anywhere in the world.
Although there is still time to save the world’s population of wild elephants, the same cannot be said for the Northern white rhino, one of the currently most critically endangered species on earth. With the United States enacting in 2016 a near-total ban on commercial trade of African elephant ivory and China announcing recently that it was banning all commerce in ivory by the end of 2017, there is hope to reverse the tide and to prevent extinction of elephants in the wild. And as more and more countries agree to make ivory trade illegal, it is hoped that the world’s ivory market will cease and that this will reduce elephant poaching. Unfortunately, the current condition of the Northern white rhino is very different. Saving the wild population of the Northern white rhino is no longer possible, as the remaining two members of this species are all in managed care and unable to reproduce.
As a result, if there is any chance to save this species, we must now turn to science. Without human intervention, the Northern white rhino will disappear forever, as it will be extinct once Najin and Fatu die. The only way to try to save this species at this point is through scientific research and recent breakthroughs. The Frozen Zoo® at the San Diego Zoo's Institute for Conservation Research was established in 1972 as a repository for skin cell samples from rare and endangered species. The goal of the Frozen Zoo® was to cryogenically preserve living cells for possible creation of future breeding programs and scientific research to rescue endangered species from the brink of extinction. At the time that the first samples were collected from animals and put into deep freeze, genetic technology was still developing and scientists were uncertain as to how the technology would evolve over time. However, they believed that in time scientific advances could use the cells the zoo was accumulating. Basically, scientists gathered the DNA, sperm, eggs, embryos and live tissue of certain animals and stored the cells at very low temperatures. This facility came to be known as The Frozen Zoo®.
At the San Diego Frozen Zoo®, these cells are maintained in metal tanks filled with liquid nitrogen and frozen to -173C (-280F). By collaborating with The Scripps Research Institute (TSRI), researchers at the San Diego Frozen Zoo are also working on developing stem cells from the frozen skin cell samples they have. They are planning to use these stem cells to assist breeding programs diversify the gene pools of endangered species. This team effort between the Frozen Zoo® and TSRI genetic engineering scientists has already produced induced pluripotent cells, which can then be used to create any other cell type, including egg cells and sperm cells. The egg cells and sperm cells can then be combined to form a viable embryo through in vitro fertilization. The result would allow animal species that are almost extinct to be re-established. This technology has already been used to create stem cells for the silver-maned drill monkey, which is a primate native to just a few parts of West Africa and the continent's most endangered monkey.
As this technology is perfected and stem cell cultures are established for many animal species, conservationists will no longer have to rely on preventing extinction by coaxing the few remaining individuals of a particular species to breed. Instead, cell lines cryogenically preserved will be added to the possible gene pool, increasing the chances of healthy reproduction. The San Diego Zoo’s Frozen Zoo® has the largest and most diverse collection of its kind in the world, although other institutions such as the University of Georgia’s Regenerative Bioscience Center and The Frozen Arc Project in England are also creating frozen zoos. Currently, San Diego’s Frozen Zoo® contains over 10,000 living cell cultures, oocytes, sperm, and embryos representing nearly 1,000 different species including one extinct species, the po’ouli. Freezing animal tissue and creating pluripotent stem cells are crucial steps in scientific advancements required to increase the reproduction and growth of endangered animal populations.
In the hopes of saving the nearly extinct Northern white rhinoceros, in November 2015, six Southern white rhino females were brought to San Diego Zoo Safari Park to serve as surrogate mothers to the Northern white rhino frozen embryos the team is planning to implant. The six young females range in age from 5 to 8 years old. These efforts are an important step in preserving the Northern white rhino population. While researchers still face many challenges ahead, they are hopeful that a Northern white rhino calf could be born within the next 10 to 15 years to one of these Southern white rhino females using this new science. And these scientific methods could also be used to preserve other critically endangered species, such as the Sumatran and Javan rhinoceroses.
Southern white rhinos almost went extinct at the end of the 19th century, plunging down to what was thought to be only 20 animals at one point. Then, in 1895 an additional population of less than 100 Southern white rhinos was discovered in Kwazulu-Natal, South Africa. With this small group of rhinoceroses, and decades of conservation efforts by numerous organizations around the globe, the population of the Southern white rhino has gradually increased. And after more than a century of successful protection and management, the Southern white rhino is no longer endangered and it is now classified as near threatened, with over 20,000 existing in protected areas and private game reserves. Locally at the San Diego Zoo Safari Park alone, over the past several years, over 90 Southern white rhinos have been born. In addition, 68 Greater One-Horned rhinos and 14 Black rhinos have also been born at the Safari Park.
If the critically endangered status of the Northern white rhino is to be changed, however, conservation efforts are no longer the answer. The only way at this point in time to bring the Northern white rhino back from the brink of extinction is through the use of genetic engineering and the efforts of dedicated scientists working with the skin cell cultures maintained in the Frozen Zoo®.
Image Source: Alyson Brown
About the Author: Alyson Brown
Alyson is a member of the class of 2019 from California.