Yunona's father, Rostislav Bukasov, told ABCNews.com that Yunona's extraordinary hiking abilities were not noticed overnight.
After a series of successful hikes during the past two years, including Utah's 11,300-foot Mount Pfeiferhorn and 11,750-foot Mount Timpanogos, and even Mount Olympus in Greece, at 9,000 feet, her parents marveled at her unique skill for her age.
"Each time Yunona beat our expectations," Bukasov said from his office at the University of Utah, where he and his wife, Olena, are both Ph.D. students. "What for many adults is perceived as too dangerous, is fun for her."
Yunona, who turned 5 in June, is a prodigy in more ways than one. The little girl can read in two languages, recognize about 50 countries on a globe and name most of their capitals, and add and subtract four-digit numbers, according to her father.
He believes hiking can be a very positive learning experience. "There are obstacles, and you need to plan in advance what you need to eat, when you need to rest," said Bukasov.
"It brings up patience and self control in children. You must be focused and concentrated and attentive in what you're doing." These are the traits he hopes to instill in his children.
Because the family does not have either a home phone or a cell phone, Yunona was not available to speak to ABCNews.com. But she told ABC affiliate ABC4 that climbing the mountains makes her feel good and said, "I like to eat when I get to the top."
21 Parks in 13 Months
Bukasov surveyed 40 of his students to find out how many of the 56 national parks they have visited and found that most have not been to more than four or five. Yunona and her family have been to 21 national parks in the past 13 months.
And Yunona isn't the only Bukasov daughter to trek nature's peaks. Her 3-year-old sister Alice is a hiker "to some extent," said Bukasov.
While hiking can be a dangerous activity, Bukasov said he prepares his family for their long hikes and makes sure that he does not over-exert Yunona and Alice.
"I would never put my children in any danger," he said. "Day care is more dangerous for their health then hiking."
"We just went to Glacier National Park. My wife is six months pregnant, and we all walked 11.6 miles. Alice walked all the way up without support. She walked down with just hand support from my wife."
Although Yunona's hikes are long and strenuous, the family stays on relatively easy trails.
"We don't do any advanced mountaineering. We do some scrambling but not technical hiking… nothing with harnesses or a lot of equipment," said Bukasov.
'We Stopped Before Her Breaking Point'
According to Dr. Andrew D. Recine, the Director of the Division of General Pediatrics at the Children's Hospital at Montefiore in New York, as long as Yunona is hiking "under a safe and controlled environment, it's fine."
There are safety risks associated with hiking for people of any age, including pulmonary edema and cerebral edema, Recine said.
"Being at a high elevation makes it a huge effort to breathe," he said.
Bukasov admits that they have overestimated his 5-year-old daughter's abilities twice but stopped as soon as they realized she was struggling. One of those time was during a trip up Mount Elbrus in Russia, when Yunona battled subzero temperatures and cold wind.
"In both cases we stopped climbing probably well before her breaking point," Bukasov said.
Their trek up Mount Elbrus taught them that "[Yunona] is still not a match for high cold wind and sub-zero temperature, but also that she survives high altitude about the same as an adult climber with the same experience," Bukasov claimed.
After her long hikes, Yunona bounces back very quickly and is ready for the next day's adventures, he said. The extent of her symptoms from long hikes is mild headaches and low appetite, according to her father. Both of these effects are common for hikers of any age at high elevations.
'I Wish My Boys Would Do That'
Bukasov, who has been hiking for years, said that through his travels he has met many hikers along the way that have pointed out to Yunona's unique abilities.
"Hikers will stop her along the way, and say 'how old are you? I wish my boys would do that,'" said Bukasov. "Some peoples take pictures of us along the way to show their families."
"I started searching on the Internet for the youngest climbers on great mountains," said Bukasov. "When we found out those children are probably grossly underrepresented, underdeveloped and perhaps over protected, we decided to do as much as we can and as reasonably safely as we can to correct this."
Yunona enjoys hiking, her father said. "Some very hard hikes she might cry once or twice, like when it gets dark… 95 percent of the time or more she loves it," said Bukasov.
Yunona plans to climb Mount Kilimanjaro in Tanzania next year, which has a summit of about 19,500 feet.
Recine, who has attempted to climb Mount Kilimanjaro, believes that as long as you properly prepare for long hikes, the safety risks go down tremendously.
"There are always safety issues of climbing," said Recine. "I don't know much about Mount Whitney, but Kilimanjaro is not a technical climb. It's not easy, but you just walk up it which is fairly safe."
"From the standpoint of bones and joints it wouldn't be a terrible risk because of her age," said Recine. "As a matter of fact, at the older end of the spectrum, the risk is greater."
