Source: San Diego Zoo Safari Park
December 1, 2019 (San Pasqual) -- San Diego Zoo Global announced the successful birth of a female southern white rhino calf on November 21 at the San Diego Zoo Safari Park—the conservation organization’s second rhino born after hormone-induced ovulation and artificial insemination. This calf’s birth also is a milestone, since she is the 100th southern white rhino born at the Safari Park.
Artificial insemination of southern white rhinos has rarely been successful in the past; this is only the second successful artificial insemination birth of a southern white rhino in North America. The first was Edward, born to mom Victoria, at the Safari Park’s Nikita Kahn Rhino Rescue Center on July 28.
The mother, 11-year-old Amani, gave birth to the healthy calf in the Nikita Kahn Rhino Rescue Center after a gestation of 498 days – more than a year and a half.
“We are so excited to welcome another healthy calf to the rhino crash at the Nikita Kahn Rhino Rescue Center,” said Barbara Durrant, Ph.D., Henshaw endowed director of Reproductive Sciences, San Diego Zoo Global. “We are very pleased Amani did so well with the birth of her first calf, and she is being very attentive to her baby. The calf is up and walking, and nursing frequently, which are all good signs. Not only are we thankful for this healthy calf, but this birth is significant, as it also represents a critical step in our effort to save the northern white rhino from the brink of extinction.”
Amani was artificially inseminated with fresh, chilled semen from southern white rhino J Gregory, following hormone-induced ovulation. Collecting and using chilled semen allows for additional generic diversity without having to move animals from facility to facility.
The artificial insemination and successful birth of the rhino calf represents a critical step in the organization’s ongoing work to develop the scientific knowledge required to genetically recover the northern white rhino, a distant subspecies of the southern white rhino. Only two northern white rhinos currently remain on Earth and, unfortunately, both are female.
“The birth of each rhino calf is a moment for celebration. Although we rejoice with each birth, we know that the recovery of a species requires collaborative work to build sustainable populations that can thrive in native habitats,” said Paul A. Baribault, president/CEO, San Diego Zoo Global. “We believe in the importance of this work because it has the potential to be applied to save other wildlife, including the critically endangered Sumatran and Javan rhinos.”
San Diego Zoo Global has been involved in efforts worldwide to save many other species from extinction. That includes breeding species once on the brink of extinction—such as the California condor and the giant panda—and in reintroductions of endangered and threatened species in their native habitats, including the Hawaiian ‘alala, the Pacific pocket mouse, and the mountain yellow-legged frog. Today, San Diego Zoo Global field programs are working to provide a future for more than 100 rare and endangered species on six continents.
Amani is one of six female southern white rhinos living at the Nikita Kahn Rhino Rescue Center. To increase genetic diversity and the number of reproductively fit individuals in North American zoos, these rhinos were relocated to the Safari Park from private reserves in South Africa in November 2015.
Five animal care specialists are dedicated to full-time care of the six female rhinos. They spend each day building a relationship with and gaining the trust of the animals. The animals are trained, through positive reinforcement, to receive needed medical procedures, as they could potentially serve as future surrogate mothers for a northern white rhino.
To reach the ultimate goal of successfully producing a northern white rhino, multiple steps must be accomplished. One of the first steps completed involved sequencing the genome of the northern white rhino to clarify the extent of genetic divergence from its closest relative, the southern white rhino. The analysis revealed that they are distinct subspecies.
Another step requires conversion of cells preserved from 12 northern white rhinos in the Frozen Zoo® to stem cells that could develop into sperm and eggs—a process successfully begun in the laboratory of Jeanne Loring, Ph.D., of The Scripps Research Institute, with details of the process published in 2011.
Reproductive options include artificial insemination, in vitro fertilization and embryo transfer, working with southern white rhinos. When these techniques are perfected, the southern white rhinos would serve as surrogates for northern white rhino embryos. There are many challenges ahead, but researchers are optimistic that a northern white rhino calf could be born from these processes within 10 to 20 years.
There are an estimated 18,000 southern white rhinos remaining in the wild. The southern white rhino is classified as Near Threatened on the International Union for Conservation of Nature Red List of Threatened Species, due to poaching threats and illegal trafficking of rhino horn. Currently, a rhino dies every eight hours in South Africa as a result of poaching.
Amani and her calf will stay in their private habitat to allow them to bond. The calf will eventually be introduced to the other rhinos living at the Nikita Kahn Rhino Rescue Center, including her potential playmate, 4-month-old Edward.