By studying species that recover from extreme stress, researchers are finding new ways to approach some of aging’s biggest challenges.
From hibernating ground squirrels to aging dogs, a new episode of Longevity Technology Unlocked makes a bold case: some of the most important clues for human longevity may be hiding in plain sight – in the animal kingdom.
Longevity science often talks like the future will be built in a clean room. Sequencing more human genomes, collecting more patient data, refining more biomarkers. But this week’s podcast asks a more humbling question. What if the answers we’re chasing are already being performed, every day, by species we’ve mostly ignored?
As host Phil Newman puts it, the episode explores “how insights from animals can really accelerate breakthroughs for humans.” That matters as this is not animal biology as scientific curiosity; it is animal biology as strategy…and possibly as shortcut.
The conversation brings together two founders working from different but surprisingly aligned directions: Daniel Oliver, co-founder and CEO of Rejuvenate Bio, and Ashley Zehnder, co-founder and CEO of Fauna Bio. One is developing gene therapies in companion animals, particularly dogs, as a bridge to human therapeutics. The other is mining extreme mammalian biology, especially hibernators, to identify drug targets that conventional human datasets may never reveal.
Their methods differ. Their argument is the same: aging and age-related decline may be more reversible than we’ve been taught to believe.
That idea comes through most clearly in Zehnder’s work. Fauna Bio studies animals that endure what would look catastrophic in humans, then recover as if it were routine. Hibernating ground squirrels, for instance, cycle through states that mimic damage most clinicians would consider serious, even life-threatening.
“These are 100 gram animals that go down to almost freezing four degrees Celsius,” Zehnder says. During hibernation, “their neurons in their brain physically retract,” while their hearts become cold and oxygen-starved. Then, every few weeks, they rapidly rewarm – an event she compares to “a mini heart attack or mini ischemia-reperfusion type injury.” And yet they recover. Repeatedly.
That is the point. Human medicine is very good at documenting how disease unfolds. It is far less equipped to study how it naturally reverses, because in humans, that reversal rarely happens on its own.
“We can study really well how disease develops in people,” Zehnder says. “But we can’t study how humans naturally, say, reverse damage after a heart attack… because it doesn’t happen that often naturally.” In hibernators, it does. On schedule.
The practical consequence is huge. Instead of sifting through oceans of human data hoping to find weak signals, Fauna Bio looks at animals actively protecting and repairing tissue in real time, then maps those mechanisms back to human biology. Zehnder’s description of this is refreshingly unromantic: “We’re actually doing is looking for a biological signal in [an] animal and then looking at the relevant human genomic network and saying, OK, what’s the human equivalent of this pathway?”
That’s a distinction, especially in a field where “animal-derived” can easily trigger public misunderstanding. Fauna Bio is not trying to make humans more squirrel-like in some sci-fi sense. It is using other species as living proof that biology can do more than we currently assume it can.
Rejuvenate Bio arrives at a similar conclusion from a different angle. Instead of studying wild adaptations, Oliver’s team is testing gene therapies in companion animals, particularly dogs, to treat age-linked disease while building infrastructure for human programs.
For Oliver, the early breakthrough was simple: “If you’re generally increasing health, you’re also treating disease.” That may sound obvious, but it runs counter to how medicine is still largely organized. We silo heart disease, kidney disease, metabolic dysfunction and frailty into separate specialties, separate drug programs, separate reimbursement pathways. Aging, by contrast, behaves more like a systems problem. The body is not a set of disconnected organs; it is a network. Tug one thread, and several others move.
Oliver says one of Rejuvenate Bio’s earliest papers made that “nexus” visible. A single therapeutic combination improved a heart failure model, kidney failure, metabolic dysfunction and even reversed a type 2 diabetes phenotype in mice.
“Cardio, metabolic, renal – all these things interact together,” he says. “And if we can generally increase the health, we’ll be able to treat all of those.”
There is also a financial realism here that makes the company worth watching. Rejuvenate Bio’s animal health strategy is not just scientifically clever; it is structurally clever. By partnering with major animal health companies, the company can move therapies toward commercialization in veterinary medicine while retaining human rights and using those revenues to fund human development. In a biotech environment still defined by fundraising cycles and capital scarcity, that is more than a business model. It is a form of survival.
Still, the most compelling thread in this episode is philosophical. Both founders return, in different languages, to the same provocation: decline is not destiny.
Zehnder says it plainly: “These things that we consider inevitable actually may be reversible.” Fibrosis, inflammation, tissue damage and functional loss – the hallmarks of aging are often treated as one-way roads. But in other mammals, some of those roads have exits. Nature has already run the experiment.
Oliver echoes that sentiment with a line that feels almost like a manifesto for the field: “There are underlying biological mechanisms that we can tap into.” That may be the deeper promise of longevity science at its best. Not the fantasy of outrunning mortality, but the practical, democratic work of learning how biology restores itself and then helping more people access that restoration.
The future of aging research may not be purely human-centered after all. It may be more ecological than that. More evolutionary. More willing to admit that we are not outside nature, but part of it. And that, in its own way, is a radical idea.
New episodes of Longevity Technology Unlocked drop every Monday, featuring researchers, founders and thinkers shaping the future of aging science. A weekly news roundup follows each Friday. Tune in on Apple Podcasts, Spotify and YouTube.
