San Diego researchers are making incremental progress in their bid to save the critically endangered northern white rhino species.
The baby rhino begins the day leading mom Livia in a lively sprint around the closed off rhino habitat on the eastern side of the San Diego Zoo Safari Park.
“Yeah, he is a bundle of energy, which is all typical rhino calf behaviors,” said Jonni Capiro, a wildlife care specialist at the Rhino Rescue Center.
The energetic new southern white rhino calf represents another incremental step in the effort to save a related rhino species that’s nearly extinct, the northern white rhino. Only two of the critically endangered animals, mother and daughter, remain alive. And they live half a world away in Kenya.
But that is definitely not on the mind of the young calf zooming around the enclosure with mom in tow. Livia takes a more deliberate pace but moves quickly enough to keep the youngster close.
“He’s really playful and confident,” Capiro said. “I think a lot of that has to do with the fact that mom is so confident and feeling good about her role as a mom. So, he doesn’t have a care in the world right now.”
And all that running makes a romp in the mud even more rewarding.
The young rhino eased up to a puddle, sniffs the water, and then lays down and rolls on its side. That mud bath cools the animal down, protects it from the sun’s harsh rays and keeps bugs off his hide.
The baby weighed more than 100 pounds at birth and is already more than twice that size. Full grown, the calf could tip the scales at more than 4,000 pounds.
And while the calf is cute and attracting attention, researchers are celebrating the birth because it is the first for the calf’s mom.
Livia is a member of a small herd of six southern white rhinos brought to San Diego from South Africa in 2015. Three have now proved they can get pregnant, carry a calf to term, and care for their offspring after they are born.
“We started getting exact details about the reproductive cycle,” said Barbara Durrant the San Diego Zoo Wildlife Alliance’s director of reproductive sciences. “We knew vaguely what the rhino cycle was like from the animals that were breeding here in our field habitats. But we didn’t know the details.”
Understanding the reproductive physiology of the large animals is critical because there is hope these six females could one day be surrogate moms to the closely related northern white rhino.
That species is on the precipice of extinction, thanks to war and poaching. The two living northern whites are both females, but they are too old to breed.
The six potential surrogates in San Diego could be a lifeline to keep the northern whites from going extinct.
“That’s the goal for all of us,” Durrant said. “All of us working on this project (want) a self-sustaining herd of northern white rhinos, (a herd) that we can reintroduce into native habitat. So, we’re backing way up and starting with the fundamentals.”
San Diego researchers hope to eventually implant an embryo of a northern white rhino into one of the proven moms. Those surrogates could give birth to a genetically pure northern white rhino.
But researchers are still working on exactly how to do that.
The hope is to use northern white rhino tissue in the San Diego Zoo Wildlife Alliance’s frozen zoo, to create northern white sperm and eggs.
Researchers are designing the process from scratch even basic steps like the Petrie dish culture needed to allow a fertilized egg to grow had to be worked out.
“So we’ve sort of taken protocols that we’ve learned for the horse,” said Carly Young, of the San Diego Zoo Wildlife Alliance. “And other protocols that I’ve learned using the domestic cat, deer, even human, and we’ve taken all of those protocols, this is how we’ve made the maturation media for the rhino. Because no one’s ever done this work before.”
Eventually, Young and the reproductive science's team will help create a northern white embryo.
“I have no doubt that we can produce northern white rhino embryos,” Young said. “In the near future, we could do an embryo transfer and figure out our technique to do this and actually be able to produce a northern white rhino calf.”
But challenges remain.
Durrant wants proof of concept in the field with southern white rhinos before they tap their limited supply of northern white cells.
German researchers have created northern white embryos using eggs harvested from the two living females. But creating the embryo is only half the battle.
“There’s never been a successful embryo transfer in any rhino species,” Durrant said.
But there has been incremental progress.
Two members of the herd in San Diego got pregnant from artificial insemination, the first time that was done in North America.
And the team knows more about the rhino reproductive tract, and the animal’s reproductive cycle.
And three females are now candidates for attempts to implant a southern white rhino embryo.
But the clock is ticking.
“The northern white rhino is so close to extinction now,” Durrant said. “There’s a very real possibility that before we have a northern white rhino calf that both of these females will be gone.”
That could mean researchers might actually bring a species back from extinction.
And the work being done in San Diego could help other rhino species as well.
Durrant said the population of the Sumatran Rhino has fallen to about 60 living animals. That species might also benefit from an intervention before the herd becomes too small to sustain itself.
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