Nola, one of just four endangered northern white rhinos left in the world, died Sunday at the San Diego Zoo Safari Park. 
 
 The 41-year-old rhino had been under veterinary care for a bacterial infection and age-related health issues. Her condition took a turn for the worse over the weekend, San Diego Zoo Global said in a statement. Early Sunday morning, the Safari Park team “made the difficult decision to euthanize her.” 
 
 It is a crushing loss for the Safari Park, where Nola had lived since 1989. The gentle 4,000-pound animal was a favorite with the staff because of her sociable personality and love of back scratches. She was also a popular attraction for Safari Park visitors, who could always spot her because of her distinctively curved horn. 
 
 Nola’s death is also a blow to the northern white rhino sub-species. After decades of poaching, there are now just three northern white rhinos left in the world. All three — a male and two females — live on the Ol Pejeta Conservancy in Kenya. 
 
 The source of Nola’s lingering infection was recently traced to a large abscess deep in her pelvic region. Veterinarians performed a minor surgical procedure to drain the abscess on Nov. 13, and the majority of the infected material was removed. But her condition began rapidly deteriorating on Saturday, and the decision was made to euthanize her. 
 
 “It sounds corny, but with her, every day is a blessing,” lead keeper Jane Kennedy said last month, when she and her fellow Safari Park staff members were keeping an eye on Nola’s condition. “I would call her a symbol of our purpose. She truly represents what we are all dedicating our lives to.” 
 
 Nola had been caught in the Sudan when she was approximately 2 years old. She came to the Safari Park in 1989 from the Dvur Kralove Zoo in the Czech Republic as part of a breeding program. But she and her fellow northern whites had already made a big impression on her new hosts. 
 
 “I met Nola and her group of rhinos in July of 1986, when I traveled to what was then the Czech Soviet Republic. The Soviet Army was there, and so was this group of northern white rhinos,” said Oliver Ryder, director of genetics, Kleberg Chair, San Diego Zoo Institute for Conservation Research. “The last week I was there, a baby rhino was born. It made a big impression on me because these enormous creatures were so gentle and so cautious and curious with this baby rhino. I was impressed yet again that there is a depth to their lives that we don’t understand.” 
 
 The hope was that Nola would mate with Angalifu, the Safari Park’s northern white rhino male. The mating happened, but there was never a pregnancy. At one point, staffers sawed off the horns of Nola and fellow female, Noti, to keep them from fighting Angalifu off. But without herd behavior to spur more frequent mating, there were never any northern white births at the Safari Park. 
 
 And then, there were fewer northern white rhinos altogether. Noti died in 2007, and Angalifu died last December. And in July, Nabire, a female northern white rhino living in the Dvur Kralove Zoo, died at the age of 32. 
 
 So when Nola was put on medical watch earlier this year due to a sinus infection, the whole rhino-watching world began to worry. In May, she began receiving treatment for an abscess on her right hip. The life expectancy of the white rhino species, which includes northern and southern white rhinos, is 40 to 50 years. But when Nola’s abscess and the bacterial infection that it caused came back in September, the Safari Park community was on high alert. 
 
 “It’s tough. It’s like having your 90-year-old aunt get sick, and there is nothing you can do except give her basic care and keep her comfortable,” keeper Kennedy said last month, as she watched Nola recline in the shade of her Safari Park enclosure, with her companion southern white rhino, Chuck, nearby. “When her abscess came back the second time, you could tell she didn’t feel good. When her attitude sinks, ours has to jump up because we need to help her.” 
 
 For Kennedy and her fellow members of Team Nola, helping the rhino was both a priority and a privilege. And the rhino made it easy. Due to an irregularity in her hooves, Nola needed regular nail trimmings. The constant interactions with the keepers made her comfortable with human contact and usually a cinch to work with, despite her massive size. 
 
 She did not like being in her boma corral and she was not at all fond of taking her many antibiotic pills. But she loved her pedicures and her back scratches and hanging out in her 65-acre African Plains habitat with the equally sociable Chuck, who was very eager to track her whereabouts when Nola was getting her abscess drained last week. 
 
 “They are like the elderly couple who met late in life and became friends,” Kennedy said of Chuck and Nola. “I’ve known Nola for 26 years, and she is truly, truly one of the sweetest animals I have ever worked with.” 
 
 With neither of the Ol Pejeta northern white females able to give birth naturally due to advanced age or reproductive issues, it is up to science to save the sub-species. The San Diego Zoo Institute for Conservation Research’s Frozen Zoo contains viable cell cultures from 12 different northern white rhinos. Genetic materials from Nola have been preserved, and the plan was always to collect her ovaries and any viable stem cells upon her death. 
 
 With the help of in-vitro fertilization, the hope is to use the recently arrived southern white rhinos living in the Safari Park’s new Rhino Rescue Center as surrogates for a hybrid rhino, which would be created with northern white sperm and southern white eggs. 
 
 San Diego Zoo Global has one of the world’s most successful rhino breeding programs. To date, a total of 94 southern white rhinos, 68 greater one-horned rhinos and 14 black rhinos have been born at the San Diego Zoo Safari Park. As the genomic research, technology and procedures become more advanced, the goal would be to create complete northern white rhino embryos, which the southern whites would carry to term. 
 
 Nola’s legacy will live on, and not just in the hearts and minds of the people who cared for her. 
 
 “The white rhinos represent the wild places and prehistoric animals that are still with us,” said Steve Metzler, interim associate curator of mammals, who accompanied the Rhino Rescue Center’s six southern whites on their 22-hour flight from Johannesburg to San Diego. “It is devastating to think that in just a few hundred years, we can wipe that out. That is just wrong, and we need to do something about it.” 
 
 karla.peterson@sduniontribune.com ▪ (619) 293-1275 ||||| The San Diego Zoo Safari Park is absolutely 
 
 incredible 
 
 ... 
 
 staff, and so much to do that it will easily take up your entire day. I spent 5 hours with Alan as our guide for the Ultimate Safari and cannot rave enough about it. I was able to have a behind the scenes tour of the okapi barn, feed the big horn desert rams and sheep, feed giraffes, see the rhinos up close, ride around in the large truck in the fields to see African animals from cheetahs to wildebeest s, met Jahari the cheetah animal ambassador , behind the scenes tour of the elephant and watch a health check of a young male elephant, and behind the scenes tour of the tigers! It was amazing and worth every single penny. Alan was fantastic - he was extremely knowledgab le, had a fantastic itinerary, and was great to spend the day with. Would highly recommend him as a guide. The keepers were amazing and passionate about their animals telling me and my friend so many facts and interestin g informatio n. I am planning for my next visit already because I cannot simply get enough of this beautiful and amazing place. 
 
 . It is a world class facility with wide open spaces, a fantastic
– In sad but utterly inevitable news, the northern white rhino has taken another big step toward extinction with the death of Nola, a beloved 41-year-old female who had been at the San Diego Zoo Safari Park since 1989. She was one of the last four remaining members of the doomed species, and the park decided to euthanize her on Sunday because of an infection and other chronic age-related health problems, reports the New York Times. "It's tough. It's like having your 90-year-old aunt get sick, and there is nothing you can do except give her basic care and keep her comfortable," the lead zookeeper told the San Diego Union-Tribune last month. Another female died at a Czech zoo in July, and the final three survivors are all at a conservancy in Kenya. "Let this be a warning of what is happening to wildlife everywhere," the park wrote in a Facebook post. But hope for the species lives on: The zoo's "frozen" section now has genetic material from at least a dozen northern whites, and scientists hope to bring back the species with embryos that can be carried by southern white rhinos, six of which recently arrived at the park, the Union-Tribune reports. "The white rhinos represent the wild places and prehistoric animals that are still with us," a park curator tells the Union-Tribune. "It is devastating to think that in just a few hundred years, we can wipe that out. That is just wrong, and we need to do something about it." (For now, the only living northern white rhinos are two infertile females and the loneliest guy in the world.)