Humans are increasingly coming in contact with mountain lions, raising questions as to whether humans are to blame and how they can safely coexist with the large cats.
On March 29, a Canadian mother fought off a juvenile male mountain lion that was attacking her 7-year-old son outside her home, but that's not the only dangerous encounter humans have had with mountain lions, also known as cougars, in recent months. In February, a trail runner in Colorado choked a juvenile cougar that attacked him as he ran, and in September, authorities said a hiker found dead in Oregon was likely killed by a mountain lion.
These are the reasons why humans may be encountering mountain lions more often, according to experts:
Mountain lions population is expanding, biologists say
The population of cougars has been increasing steadily for decades, Jim Hayden, a biologist for the Idaho Department of Fish and Game, told ABC News.
In the 1940s and 1950s, people were paid bounties for mountain lions, according to Jim Williams, regional director for the Montana Fish, Wildlife and Parks and author of "Path of the Puma."
During the 1960s and 1970s, hunting of cougars became regulated and hunters were required to have licenses after that time period, Hayden said. In addition, in the 1980s and 1990s, conservation efforts for migrating deer and migrating elk began to pop up in the west, which increased their food source, Williams told ABC News.
"With regulated management, we've seen an increase in the mountain lion population pretty much west-wide, Canada as well," Hayden said.
"From the 60s until now, you've had a steady progression of conservation benchmarks that have brought us to the distribution of mountain lions in the west," Williams said.
And as the cats slowly reclaim habitats they have occupied for thousands of years, their populations are also distributing eastward to places that didn't used to house them, Williams said, describing the mountain lion population as the "success story" of large cats, whereas other cat populations throughout the earth, such as the African lion, is "declining rapidly."
Humans and cougars gravitate toward similar habitats
As their population thrives, mountain lions are expanding their range and "moving into areas that people aren't used to seeing mountain lions," Hayden said.
In addition, deer and elk herd typically congregate in south and west-facing mountain slopes in the winter -- areas where humans like to build homes as well due to the low elevations -- and the cougars follow their food, Hayden said.
Human populations continue to creep up "dramatically" as well, making encounters with big cats even more likely, according to Lynn Cullens, executive director of the Mountain Lion Foundation. And as they move into mountainous and hillside areas, and build properties in areas that had previously been wildland, they've understandably encountered more wildlife, including cougars, she said.
The increase of residential sprawl across states in the American west like Colorado, California and Idaho, has put people "right smack dab in the middle of mountain lion habitat," Williams said.
"It’s a beautiful place to live, but now you have to live with the mountain lions," he added.
The number of encounters reported in Idaho has gradually increased in the last three or four decades, Hayden said, adding that he expects them to be "something that people are going to see more and more of" in the future.
Humans didn't used to spend so much leisure time outdoors
In the past 50 years, humans have increasingly begun to recreate in wildland, Cullens said.
"There's been an incredible increase in the demand for outdoor recreation," Williams said.
In the 1970s, there weren't near as many campgrounds, people hiking into wilderness or an overall interest in wild, outdoor activities, she said. But, these are places where people will naturally come in contact with wildlife, and people accept that risk, Williams said.
More hunting could actually lead to more encounters
The hunting of mountain lions is legal in most of the western states, Hayden said. In states where hunting cougars is legal, the sport is regulated by the length of the season, the number of people permitted to hunt and limits on how many mountain lions are allowed to be killed, he said.
Despite the regulation, mountain lions are still continuing to be killed in "greater and greater" numbers, Cullens said.
"We're killing far more than we were during the bounty period," she said.
This could be detrimental because hunters are searching for the big prize -- often a mature, adult cat -- leaving the juvenile lions to take residence in what used to be the adults' territory, the experts said.
Dr. Robert Wielgus, former director of the Large Carnivore Conservation Lab at Washington State University, found through 20 years of research that increased hunting for cougars resulted in increased immigration by young cougars, most of them teenage males.
"For every large resident male killed, two or three young guys came to the funeral," he told ABC News. "These young cougars were responsible for increased complaints."
Younger cats haven't learned how to hunt as proficiently as their adult counterparts, leading them to make mistakes and sometimes mistake a human for food, Williams said. The juvenile lions are often the ones wreaking havoc in human communities, attacking pets and livestock, he added. Juvenile cougars were also responsible for the attacks that garnered national attention in recent months.
On the flip side, Wielgus found that decreased hunting resulted in decreased immigration and fewer complaints, he said. The trick is to keep the equilibrium of hunting to population growth. For example, in Washington, where researchers learned that the mountain lion population was increasing by 14%, hunting has been regulated to just 14%, Wielgus said.
"So, basically, what we found was that increased hunting was causing the problems, and decreased hunting solved the problem," Wielgus said.
In addition, California, which does not permit sport hunting of cougars at all, has the lowest incidents per capita of human-cougar conflict, Wielgus said.
Even still, attacks by mountain lions are still incredibly rare, according to the experts. In the past 100 years, there have been fewer than 20 human fatalities as a result of cougar attacks, Cullens said. Williams described the risk of being attacked by cougars as "extremely low."
Better technology leads to more awareness of encounters
Because technology and communication have improved dramatically, we are becoming increasingly more aware of the presence of cougars near human residences, the experts said.
In addition to people having access to cameras at all times, surveillance cameras attached to properties also capture the cats as they roam residential neighborhoods, Cullens said. In addition, the advent of social media allows people to share these images to a wide audience, she said.
And once people are aware that the cats are near, they'll start to see them more.
"Once you begin to look for mountain lions, and you live in an area where mountain lions exist, you'll likely see the mountain lion that was always there," she said.
The "cryptic animals" are the "ghosts" of the animal kingdom, Williams said.
"You don't see cats, but most of the time they see you," he said. "They're very difficult to spot."
What to do if you encounter a mountain lion, according to the Colorado Division of Wildlife
-- Do not approach a lion, especially one that is feeding or with kittens. Most mountain lions will try to avoid confrontation. Give them a way to escape.
-- Stay calm when you come upon a lion. Talk calmly yet firmly to it. Move slowly and never turn your back on it.
-- Stop or back away slowly, if you can do it safely. Running may stimulate a lion's instinct to chase and attack. Face the lion and stand upright.
-- Do all you can to appear larger. Raise your arms. Open your jacket if you're wearing one. If you have small children with you, protect them by picking them up so they won't panic and run.
-- If the lion behaves aggressively, throw stones, branches or whatever you can get your hands on without crouching down or turning your back. Wave your arms slowly and speak firmly. What you want to do is convince the lion you are not prey and that you may, in fact, be a danger to the lion.
-- Fight back if a lion attacks you. Lions have been driven away by prey that fights back. People have fought back with rocks, sticks, caps or jackets, garden tools and their bare hands successfully. Target sensitive areas like the eyes and nose. Remain standing or try to get back up.
ABC News' Morgan Winsor contributed to this report.