When hibernating yellow-bellied marmots emerge in spring, they are the same age, biologically speaking, as when they first curled up in their dens eight months ago. The new study, published last month in Nature Ecology and Evolution, could help scientists find the key to slowing the aging process in humans.
The marmots' anti-aging abilities may be linked to metabolic changes in their bodies that occur as they undergo deep hibernation, reports Holly Barker for Discover.
Because hibernators are less at risk for predation and less exposed to pathogens, their lifespans tend to be longer than non-hibernating species, according to previous research.
In the new study, however, scientists suggest hibernation can halt aging altogether.
The cat-sized, butter-colored rodents live about 15 years on average, a longer-than-expected lifespan for a rodent their size. To observe how marmots seemingly tap into a fountain of youth, researchers tracked them from the moment pups emerged from their burrows.
The study focused on female marmots because they stay close to their natal burrows throughout their lives, wheres as males leave and return, reports Erin Moody for Earth.com. In total, experts gathered blood samples from 73 female marmots. For 14 summers, biologists took blood samples every two weeks from marmots near their burrows.
To determine what metabolic changes occured during hibernation, the team measured epigentic markers, which are natural alterations to DNA that develop over time as one ages. Over time, few epigenetic changes occurred in the marmot's DNA during hibernation. So, biologically speaking, the marmot did not age since first falling asleep—but hibernating isn't the eight-month nap it may seem to be.
When marmots hibernate, they undergo metabolic suppression. Their body temperature drops to 41 degrees Fahrenheit, just above freezing, and their body fat drops up to a gram per day, reports Jennifer Walter for Inverse. While hibernating, the animal "feels like a cold, fuzzy rock,” says study author Dan Blumstein, a UCLA biologist, to Inverse.
They cycle between two weeks of torpor, or inactivity, with just a few interspersed hours of arousal, or increased metabolism. This transition from inactivity to arousal is thought to activate cellular activity linked to aging, like oxidative stress, reports Discover. By suppressing arousal events, they may be slowing down the aging process. As they hibernate, the marmot's DNA methylation slows down and starts back up again when they emerge in the spring, which could be another way they extend their lifespans, per Discover.
The find may aid doctors in developing better ways to preserve organs for transplantation by preventing DNA methylation marks on the tissues. It could also help NASA scientists find a way to mimic hibernation for long-term spaceflight missions beyond the scope of the typical human lifespan, Earth.com reports.