Exploring human aging via elephant research

Indiana University researcher Daniella Chusyd is studying human aging in an unlikely way: through elephants.

Humans and elephants have similar lifespans, with elephants capable of living into their early 70s. Chusyd wants to determine how different elephant species live so long without the benefit of medicine and science. Her research also aims to better understand the impact human activities can have on elephant health and aging, which can inform strategies and policies that allow humans and elephants to coexist.

Elephants and humans are similar in some key characteristics, such as lifespan and sociality, but they took very different evolutionary paths. If we can identify some of the unique strategies that have evolved in elephants, we can better understand healthy human aging, too."

Daniella Chusyd, Assistant Professor, School of Public Health-Bloomington, Indiana University

Elephants have approximately 20 copies of the TP53 gene -; also known as the "guardian of the genome" -; when most other mammals, including humans, have just one. This makes them more sensitive to detecting DNA damage and less likely to grow tumors or develop cancer. The gene is also involved in general aging processes, so understanding its role is helpful to Chusyd.

Over the past six years, including during her time as a postdoctoral researcher at IU, Chusyd's research has taken her to Africa -; specifically Zambia, Republic of Congo and Uganda. She studies the factors that have impacted elephants' health and aging, such as early-life trauma, pollutants and the role of human activities. Her work focuses on both species of African elephants, savanna and forest.

Illegal poaching and human-elephant conflict have long plagued elephant populations, but the lasting implications of experiencing such trauma is not known. In Zambia, Chusyd is comparing orphaned elephants to those living in intact families to determine the long-term health and behavioral effects of experiencing early-life trauma. This research is funded by the National Institute on Aging and in collaboration with Game Rangers International.

"We know children who experience early-life adversity are, on average, at increased risk for later-life diseases and a shorter lifespan," Chusyd said. "Elephant calves are similar to children in that they rely on their family for stability, support, reassurance, learning and all the things needed to be a successful elephant. They are highly social, display a range of emotions and have exceptional long-term memory, so we want to know whether there are similar long-term implications in elephants who experience traumatic events early in life as well."

Chusyd and her team investigate this through a natural experiment, where some elephants randomly became orphans while others did not. Orphaned elephants do not have the intergenerational transfer of trauma that is often observed in other mammal populations, specifically humans. This helps the researchers untangle the impacts of traumatic events on health outcomes, pace of aging and behavior.

In addition to studying the orphaned elephants, many of which are still under human care due to age, GPS collars have also been placed on 10 non-orphaned elephants. An app on Chusyd's phone allows her to monitor their location in real time. Her team films each elephant's actions to gather behavioral data; collects dung and urine samples for hormone analyses, parasite load and microbiome; and collects small skin samples to test for DNA methylation and gene expression. Combined, the data gives Chusyd a holistic view of each elephant's health.

Chusyd also works out of the Makerere University Biological Field Station in Uganda's Kibale National Park. The Ugandan Albertine Rift is the largest known hybrid zone, where African forest and savanna elephants crossbreed. Hybridization is a widespread phenomenon and can have important evolutionary and ecological consequences. Chusyd and her team are investigating how hybridization contributes to elephant physiology, and they hope to ultimately understand whether a more diverse genetic makeup increases physiological or behavioral flexibility in the elephants' rapidly changing environment.

Alec Iruri-Tucker, a graduate student in the IU School of Public Health-Bloomington, is in Uganda through August collecting elephant dung to assess the prevalence of microplastics and the presence of antibiotic-resistant pathogens.

"Seeing elephants, either in the forest or in the savanna, is something that never loses its charm," Iruri-Tucker said. "While the process may sound less charming, a lot can be learned from collecting their dung.

"Through analysis, we can gain insight into their health, as well as the ways that humans are impacting their environment, such as the presence of microplastics or pollutants that elephants may have ingested. This is important for understanding the relationship that humans have with the environment and the health outcomes for both humans and animals."

Through the years, human populations and activities have severely reduced forest elephant distribution and abundance. Central Africa is the major remaining habitat for forest elephants, but on the periphery of protected areas, human populations are rapidly expanding and relying on agriculture. This has led to increased occurrences of elephants eating farmers' crops, known as crop raiding. In Congo, Chusyd is collaborating with the Wildlife Conservation Society to understand the conditions that drive elephant crop raiding and get the buy-in of people living with and among elephants.

Here, her team can visually identify over 500 elephants and track their movements in various ways -; including by footprint, mucus drops and transference of mud from their body to a tree -;to find and collect their dung, which can be used for further testing.

Recently, Chusyd began studying various pollutants that exist in Zambia to gain insight on how pollutants move within the environment through the elephants. She hopes to better understand whether certain elephants -; because of species, early-life adversity, age or sex -; are more capable of tolerating and handling environmental pollutants than others.

Chusyd hopes her research can also help advise conservation policy in Africa. The GPS collars, for example, show where "elephant highways" exist, which can inform decisions about area infrastructure improvements. Her research on pollutants can demonstrate what humans may also be ingesting, affecting their health.

"If we can gain a better understanding of how elephants are using their space and what they are getting from it, we can look at smarter ways to build or use the environment such that everyone can coexist in the best way possible," Chusyd said. "My intention is that this research can help inform policies and decisions that impact all individuals -; people, elephants and other species -; who use the land."

Chusyd is looking at ways to expand her research in Africa, and she plans to return later this year to train field and research assistants in new methodologies. But what she looks most forward to is returning to the elephants and watching them thrive in their natural habitat.

"There aren't many things that can top watching 100 or 200 elephants all in one place at the same time interacting with one another -; from little babies playing and chasing off birds to the adults," Chusyd said. "It is such an incredible experience to be a fly on the wall in their world, and I'm unbelievably grateful for the opportunities my research has allowed."