A new study shows that female elk get wiser as they age, and use that wisdom to remain elusive and avoid hunters.

Henrik Thurfjell, ecologist at the University of Alberta, Canada, and fellow researchers monitored nearly 50 female elk in western Canada using GPS tracking collars from 2007 to 2012.

Their goal was to find out whether female elk that are innately more cautious than others are the ones that survive through hunting seasons and live longer, or if elk adjust their behavior as they age to become more stealthy.

Male elk are the more popular targets for hunters, and are much less likely to survive past 5-years-old, while female elk, if strategic enough, can live up to 20 years.

The study time frame allowed the researchers to observe the elks’ patterns over seven hunting seasons, in an area range of 17,760 square miles in Southwestern Alberta and Southeastern British Columbia.

The team found that, with each passing hunting season, the female elk that survived got progressively better at avoiding hunters in the next seasons. They learned to move less overall, and cover less ground during the hunting seasons. They also stayed in areas with dense forests and rocky terrain.

The researchers found this to be especially true during peak hunting hours, like dawn and dusk. The elk even showed evidence of hanging around rugged terrain more often during bow-hunting season than rifle-hunting season, according to the study. Bow-hunters have a harder time stalking their targets in rugged terrain, and need to get close to the animal to get a good shot, while rifle-hunters can post up hundreds of yards away and still get a shot.

Overall, the researchers concluded that elk learn to adapt and alter their behaviors as they age, showing that social learning, not just natural selection or selection by hunting plays a crucial role in how older elk thrive.

The response is not genetic, so even though hunters are altering the age and sex composition of the population, it is unlikely that hunting is having substantial long-term consequences on these elk, according to the authors.

“Our results indicated that both human selection and learning contributed to the adoption of more cautious behavioral strategies in older females,” the study authors wrote in PLOS ONE.

According to Mark Boyce, conservation biologist at the University of Alberta, the “magic age” for female elk is 10-years-old. If they survive that long, the elk become nearly “bulletproof” thanks to their behavioral tactics and can successfully avoid hunters and their weapons of choice.

“Female elk are indeed almost invulnerable to human hunters when older than 9 to 10, confirming that experience contributes to their survival,” wrote the authors.