Female elk are able to learn when hunters are using either rifles or bows, and as a result, alter their behavior to make it harder for the hunters to get their shot.
As one of the largest species of deer, the main predator of elk is humans. If you see an old animal, then the odds are it will be female, as the males rarely make it past five years of age, as they are often shot for their antlers. But it seems that the older the females get, the better they become at avoiding humans and their weapons, and when they reach around 10 years of age, they are nearly invulnerable from human hunters.
The researchers wanted to clarify whether the survival of female elk was being driven due to the selective hunting by humans – in which the boldest animals are most likely to be killed while the reclusive ones more likely to survive – or if they are showing adaptive responses and learning over time to temper their outgoing behavior.
By tagging dozens of female elk of a wide range of ages in Canda, and following them over a period of a few years, the researchers studied how they moved through the environment, and how this changed with time. Published in PLOS ONE, their findings showed that while the selective pressure from hunters was impacting the animals, there was also a learning aspect to their movements.
Over time, the animals realized that if they moved less, they could lower the chance of being spotted by hunters. They also adapted their behavior and habitat preference depending on how risky the region they were moving through was. For example, the animals were more likely to stick to steep terrain and forests if feeding near roadsides, which are often used by hunters to spot their quarry.
Amazingly, it turns out that the elk seemed to be able to recognize if the hunters were more likely to be using bows or guns, and in turn alter their behavior as a result. During bow season, which requires them to get much closer to the animals in order to take a shot, the elk would stick to more difficult ground. While during the season in which hunters tended to use rifles, the animals would avoid the roads and stay in more remote and inaccessible areas.
Rather than know what season it was at any specific point of the year, the researchers think that the elk were instead taking their cues from the behavior of the hunters. When rifle season is in full swing, hunters tend to slow down on the roads so that they have a better chance of spying the deer. It seems that the elk have learned this as they age, and as a result stay away from the roads and stick to forests during this period of time.
It seems then that the behavioral adaptations of the female elk are a mixture of innate responses driven by selective hunting, and learned responses as the cows age.