The World Wildlife Foundation South Africa created the event in 2010 to bring awareness to the five remaining species of rhinos -- black, white, greater one-horned, Sumatran and Javan -- and their diminishing numbers in the wild.
"Poaching is just astronomical at this time, and there are questions as to whether these species are even going to remain within the next decade," said reproductive physiologist Monica Stoops, of the zoo's Conservation and Research of Endangered Wildlife, or CREW. "Right now, they say every eight to nine hours a rhino is poached."
In addition to conservation efforts abroad -- including returning Sumatran rhinos Andalas and brother Harapan to the Sumatran Rhino Sanctuary in Indonesia -- the Cincinnati Zoo works to help ensure a genetically healthy population of rhinos continues to grow in captivity.
Stoops and a team of experts recently published a paper detailing their success on breeding Indian rhinos using artificial insemination and cryogenically frozen sperm. Two years ago, the procedure produced calf Monica -- Stoops' namesake -- at the Buffalo Zoo with Cincinnati Zoo Indian rhino bull Jimmy, who died in 2004.
"Jimmy had been dead 10 years prior to being used for that procedure," she said. "So he's down stored in our cryo bank, and he got thawed out and then … he came to life and created a calf there in Buffalo. He has important genetics -- none of his family line remained, so he's kind of gotten reinfused back into the population, and he became a first-time dad."
To ensure certain members aren't overrepresented in captive rhino population, Stoops said, the Species Survival Plan carefully determines the best genetic matches. While the goal is to allow animals to breed naturally, the process can be challenging with Indian rhinos because they often encounter personality conflicts leading to aggressive behavior and injury while attempting to mate.
"Sometimes you can have a male and female who just don't get along," she said. "So even though you spent the time and the money to get each individual that should be genetically matched together, they don't get along and you don't get breeding, or you get serious problems that can happen."
When nature doesn't prevail, Stoops said humans step in. The process involves using stored sperm housed in CREW's cryogenics lab, which Stoops said is thawed and then hand-carried to its intended destination, getting VIP treatment through airport security. She said the latest step involves sorting the sperm into X and Y chromosomes to be able to predetermine sex, a process conducted at Sea World Reproductive Center in San Diego. She said the team there successfully used sorting techniques in reproduction for dolphins, killer whales and now rhinos.
"Once we get there, they start the sorting process, and it takes them all night," she said. "So usually we'll get there around 9 o'clock at night, and then they're sorting all the way through that night, then freezing it after it comes off the sorter."
Because females are currently more genetically valuable, they usually use the sorted X sperm for upcoming artificial insemination procedures.
The next step in their Institute of Museum and Library Services-funded research is to expand the procedure to other species, Stoop said. On a recent trip to the Indianapolis Zoo, she showed staff there how to perform artificial insemination on a white rhino. She said she hopes to educate other facilities on how to achieve success.
Most recently, she said, the Denver Zoo performed artificial insemination procedures on their own Indian rhinos using specimens from CREW's lab.
"We really want to empower others," she said. "It's not only specialists -- you guys can do this. You can learn to monitor your animals and ultrasound them and you can do it yourselves."
In the wild, Stoops said, female rhinos become pregnant, give birth, lactate, then start the process all over again. She said when that process is disrupted, as it often is in captivity, females develop cysts similar to endometriosis in humans, which can prevent pregnancy. At the Buffalo Zoo, head rhino keeper Joe Hauser said they faced that exact situation with their aging female Indian rhino. He said their female had successfully given birth to two calves in the past, but their newest bull was far too young to breed at age 4, not reaching maturity until age 8 to 10.
"That's why we did (artificial insemination), because our male wasn't going to be breeding age possibly up to six years," he said. "And if we waited another six years for our adult female, most likely she would have been out of the reproductive cycle then."
The successful procedure produced now 2-year-old Monica, weighing in at a healthy 2,010 pounds -- just a few pounds shy of her mom, Hauser said. While the Species Survival Plan suggested a list of potential candidates for their female, Hauser said he and Stoops agreed that Jimmy was their first choice.
"And he was obviously very successful," he said. "It took it on the first time. For timing-wise on the (artificial insemination), we didn't do any hormone injections or anything -- we did everything off her natural cycle. So we got the timing right and Jimmy's cells were healthy, so it was perfect."
This week, the Buffalo Zoo will also be promoting World Rhino Day.
In August, Hauser said, they raised more than $14,000 at their annual Bowling for Rhino event, an all-time record for their facility.
The Cincinnati Zoo will hold its own Bowling for Rhino event Oct. 1, from 5 to 10 p.m. at Stone Lanes in Norwood. While these types of events are fun-based, Hauser said, they're also a great way to spread awareness to the community.
"We have to spread the message and let people know what the state of the rhino is," he said. "I don't think a lot of people are aware rhinos are so rare. So it's very important, and it's part of my job as a keeper, when people come through the door at the zoo, to make sure they're aware of the state of the rhino and what we have to do to protect them in the wild, as well, and zoos."