New rhino mom could play role in saving near-extinct subspecies

A seven-week old rhino calf is the newest star attraction at the San Diego Zoo Safari Park, and visitors are delighted at the sight of the youngster frolicking through the enclosed area he shares with his mother.

While the sight itself is a marvel to watch, many guests likely don’t know the behind-the-scenes wonder that scientists are working on at the park, as the new mom could play a role in saving a subspecies from extinction.

Just in time for World Rhino Day on Thursday, the park revealed the calf has been named Neville, which was chosen by a San Diego Zoo Wildlife Alliance supporter in honor of a South African doctor who made a positive impact on the donor’s life.

Neville was born Aug. 6 at Safari Park’s Nikita Kahn Rhino Rescue Center to first-time mother Livia, who had already proven to be a responsible parent after becoming the surrogate mother to a calf that was neglected by his mother.

Livia and Neville are southern white rhinos. About 9,600 miles away, the last two northern white rhinos on earth are in a wildlife conservancy in Kenya. Both are female, and neither is a candidate for traditional artificial insemination because of their age and physical condition.

In another era, that would spell the end of the line for northern white rhinos. But with Livia and other rhinos, extinction may be averted through banked genetic material from the San Diego Zoo Wildlife Alliance’s Frozen Zoo, which contains more than 10,000 living cell cultures, oocytes, sperm and embryos, the largest collection of its kind in the world.

Livia is one of six rhinos dedicated to the Northern White Rhino Initiative at the rescue center, and someday she could be a recipient of an embryo developed by scientists with material from the Frozen Zoo, said Barbara Durrant, director of reproductive sciences at the San Diego Zoo Wildlife Alliance.

“No one’s ever done a successful embryo transfer in any rhino species,” she said. “That’s a whole technology that needs to be developed.”

The first successful transfer is likely to happen at the rescue center because the rhinos there are conditioned to have ultrasounds done on them while standing up and without anesthesia, Durrant said. That’s important because the ultrasound will show the reproductive cycle of the rhino, allowing scientists to perform the embryo transfer at just the right time.

Wildlife care specialist Scott Smith said the rhinos at the center are conditioned to be calm around people through positive interactions with people. Neville has been enjoying the attention, he added.

“He likes belly rubs, thigh rubs, all of it,” Smith said. “We use it as kind of a re-enforcer for them and to make sure we’re a positive in their life.”

Southern white rhino Neville is seen frolicking at Safari Park.

Southern white rhino Neville was born Aug. 6 weighing about 110 pounds and now is 250 pounds. When fully grown at about 3 years old, he will weigh between 4,000 and 5,000 pounds and stand 6 feet tall at his shoulder.

(Don Boomer/For The San Diego Union-Tribune)

The first embryo transfer will be with a southern white rhino as a test. If successful, Durrant said the next step will be transferring a northern white rhino embryo.

Scientists are at work creating a white rhino embryo, which Durrant said could be cloned by fusing a northern white rhino cell with a southern white rhino egg.

A more complex possibility is to take northern white rhino cells, program them backwards into stem cells and then forward into sperm and eggs to create a pure northern white rhino embryo.

It may sound like science fiction, but Durrant said the first steps have already been taken.

The Frozen Zoo includes northern white rhino sperm and 12 cell cultures from 12 animals. Scientist Marisa Korody is working on the project as part of the conservation genetics team headed by director Oliver Ryder.
Durrant said nine of the 12 cell lines have been programmed back to stem cells.

“It’s going to be a very long process before we get sperm and eggs, but that’s the goal,” Durrant said.

White rhinos are one of five species of the animal, and while the northern and southern rhinos are hard to tell apart on sight, Durrant said there are differences, and the northern subspecies is worth saving.

“It’s important to have those animals back in their native habitat,” she said about the northern white rhino, which once roamed Chad and the Congo region.

“They’re basically ecosystem engineers,” she said. “They keep the grasses down, which makes it easier for the predators to see their prey. If you take them out, the grasses grow so high the predators can’t find the prey and the habitat becomes off-balanced.”

If successful, the breeding program could produce a new herd of northern white rhinos, and Durrant said the herd could be strong because of the genetic diversity of the cells in the Frozen Zoo.

“Genetic diversity allows a group of animals to withstand environmental influences and events,” she said. “If they were all genetically similar and did not have varying degrees of resistance, say to heat or to cold or to drought, then they would all die. But with genetic diversity, you have some that can withstand this and some that can withstand that, so some would die but not all.”

Livia and Neville are also helping with genetic diversity. Because Livia was born in the wild, she has added new genetics to the North American rhino population, and those genetics have been passed on to Neville.

“So he’s important in and of himself,” she said while watching Neville dart around the rhino exhibit one recent morning. “And besides, he’s just impossibly cute, right?”

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