Since the April morning he was born in 1962 – in fact, even before he was born – Packy has been broadening human understanding of Asian elephants.
For his entire life, Packy has been a wonder not only for adoring crowds visiting the Oregon Zoo, but for scientists around the world trying to understand an elusive and endangered giant mammal. Fifty-two years later, as the oldest male Asian elephant on the continent, Packy is helping researchers understand yet another thing about elephants: what happens when they age.
It's a familiar story for humans, too. Packy's changing as he enters old age – in ways that are hard to predict.
A key example: the different way Packy is experiencing a normal male elephant cycle called musth, a remarkable increase in testosterone, secretion of pheromones and loss of appetite, that usually lasts a couple of weeks. Though they don’t fully understand it, scientists believe musth is a period when wild male elephants can indicate virility or try to establish dominance over other males.
In the wild, elephants usually experience musth on an annual basis. So has Packy, who has long gone through musth right around his birthday.
"In the past, Packy has been like Old Faithful," said Bob Lee, the zoo's elephant curator.
The data collected by the Oregon Zoo on the musth cycles experienced by Packy and his fellow male elephants, or bulls, has been extremely valuable to scientists’ understanding of elephants, said Janine Brown, a reproductive physiologist at the National Zoo's Center for Species Survival.
“Decades ago the Oregon Zoo staff had the foresight to recognize the importance of routine blood collection for understanding elephant biology,” said Brown via email from Thailand, where she is conducting fieldwork on elephants. “As a result, most of what we know of hormone changes during musth are based on samples collected from Oregon Zoo bulls, including Packy.”
But as he ages, Packy is falling off this regular schedule. For about a year, he has been experiencing erratic cycles of musth, puzzling zookeepers and veterinary staff but also possibly providing new insight into what aging means for an elephant. Elephants can sometimes live to be 70, but a bull in his 50s is unusual, Brown said.
"We've made so many discoveries about elephants at this zoo, and this is another one," Lee said.
Packy's irregular musth cycles might not be a problem in themselves, but they are also complicating zoo veterinarians' treatment of his tuberculosis – which was already complicated enough.
Tuberculosis has been observed in elephants for nearly 140 years, in the wild and at zoos. As with humans, it is usually controllable with medication and often does not manifest itself in visible symptoms. The zoo routinely checks its elephant herd for TB as part of its comprehensive health program, said chief veterinarian Tim Storms.
Packy was diagnosed with TB in December 2013, several months after one of the zoo's other male elephants, 30-year-old Rama. A third male elephant, 44-year-old Tusko, was diagnosed with TB in June 2014. All three elephants are experiencing what veterinarians call a "subclinical infection," meaning they appear healthy and have not exhibited signs of TB. Still, zoo veterinarians have responded quickly to prevent the disease from spreading, separating the three from the rest of the herd.
All three elephants have been treated with the same proven medication – Isoniazid, which is also used in humans with TB. The drug is recommended by the U.S. Department of Agriculture, which regulates zoos. It is used in combination with other medications under individual treatment plans for each elephant, Storms said.
Rama and Tusko have responded well to their treatment plans. Rama was recently declared "non-contagious" and allowed back into public viewing areas and closer proximity to the herd.
But for reasons veterinarians don't fully understand, Packy has experienced more side effects from Isoniazid – perhaps because of his age, perhaps because of other factors. Veterinarians have tried four different treatment regimens with differing doses of the drug and combinations with other medications. But each time they have had to stop, because of worrying side effects like elevated liver enzymes and loss of appetite.
That's where Packy's suddenly erratic musth makes his TB treatment even more difficult, Lee said. Since his latest onset about a month ago, veterinarians have stopped treatment altogether while they wait for Packy to regain his appetite and put on some weight he has lost during musth.
Instead, zoo veterinarians are working to develop a new treatment plan, which may include different medications. Any new treatment plan would need to be approved by the USDA.
In the meantime, Packy and his companions continue to help researchers across the scientific community understand the life cycle of Asian elephants, fewer than 40,000 of which remain in the wild.
Nearly every part of Packy is closely monitored, from blood and saliva to dung and tusks, which along with data from other elephants at the zoo has helped build one of the world's largest catalogs of biological and behavioral data about Asian elephants.
Zookeepers hope data from the elephants will help improve understanding of elephants not just in zoos, but also in the wild.
“Zoo elephants provide opportunities to study species biology in a way that is often not possible, or practical, to do in the wild,” Brown said. For instance, she noted, data from the Oregon Zoo helped scientists understand the reproductive cycles of female elephants and elephants’ social behavior.
“This information allows us to better understand population dynamics of wild elephants in relation to changes in climate and resources,” Brown said.
The zoo has also begun a particularly extensive long-term study to analyze the elephants' response as they move to the new "Elephant Lands" habitat now under construction.
The habitat will transition the elephants from a small exhibit constructed over 55 years ago to an expansive indoor/outdoor space where they will have far more choices about where to go and what to do, something that's especially important to elephants, said Nadja Wielebnowski, conservation and research manager for the zoo.
Not every elephant will handle the change the same, Wielebnowski said, which could help inform greater understanding of animal personalities. "They all have their own personality," she said. "We will need to take that into account."
Researchers will closely monitor stress hormones in the elephants through fecal samples as well as the regular blood samples that have been taken weekly for many years.
Packy might be a little more hesitant about the change, like some adults with new technology. "He's not what we'd call an early adopter," Wielebnowski said.
But however he handles the change, researchers and the public will be watching Packy especially closely – as they always have.
"He's teaching us now, just like he has since birth," Lee said.
Learn more about elephants at the Oregon Zoo