The Eastern Sierra Interpretive Association hosted another talk on Thursday, February 3, as part of its Winter Adventure Series hosted at the Mammoth Welcome Center. 

The talk, called “Mountain Lions Demystified,” featured Phil Johnston: Mountain Lion Researcher, Professional Tracker, and Outdoor Educator. 

For the past 20 years, researchers have been putting GPS-collars on mountain lions in order to gain an understanding of their private lives. Information scientists have been able to gather includes mountain lion diet, movements, kill rate, habitat use, and interspecies competition.

With the help of his dogs, Johnston himself tracks mountain lions, traps them, collars them, and then releases them back out into the wild in order to track their behavior. 

“I’m going to talk about this from a naturalist perspective,” said Johnston. “I am a scientist, but what I am going to speak on are things that I have seen firsthand; none of this is stuff that I’ve read about or heard someone tell me secondhand. I will come at this from the perspective of a woodsman, a houndsman, and a naturalist.”

According to Johnston, there are three things that define mountain lion behavior: prey, terrain, and competition. 

“These creatures are made to move, devour land, and find a place to call home,” explained Johnston.

Mountain lions do not have a designated mating season like other wild animals. Instead, they have a 27-day estrus cycle that is triggered whenever females are not nursing or raising dependent kittens. 

“When females are done nursing, they have dependent young for up to 4 months, and at some point when those dependent young can function on their own, the female enters estrus again,” said Johnston.

The female then breeds again, and after a 3-month gestation period, will give birth to 2 to 4 kittens. Kittens spend about 24 months together with their mother before dispersing from their mother’s home range to be on their own. 

“For the vast majority of a female mountain lion’s life, she will have dependent young,” said Johnston. 

After dispersing from a mother’s home range as a young animal, lions will travel hundreds, if not thousands, of miles as they figure out where they want to call home. They will then establish a home range of their own – an area around an epicenter from which they will not traverse beyond. 

The average adult female home range size is about 150-400 square miles. The average adult male home range size is about 200-700 square miles. 

“In my career, I’ve studied a lot of different carnivores’ home range sizes. For example, the Gray Fox has a home range size of about 1-2 square miles, while the Ringtail Cat has a home range of about 40 square miles, despite being much smaller. It’s interesting to learn about different life strategies and how different animals have different home ranges; it all relies on what they’re eating, and what they’re living on,” said Johnston. 

Why do mountain lions have such a big home range? Prey availability. More specifically, deer availability. 

A typical lone, adult mountain lion finished one deer in about 90 hours. A pack of 4 can eat an entire deer in 24 hours.

“There is a huge energetic demand on the adult female mountain lion to hunt and kill an adult deer every day or two in order to feed her kittens. You can’t do that within one square mile; if you tried to, you would quickly kill all the deer in that area and then starve. That’s why these lions have home ranges of hundreds of square miles, so that they can encompass enough area to be able to make laps and kill deer without wiping the deer population out,” said Johnston.

Female home range size is therefore dictated directly by prey availability. This is very much observable and quantifiable; for example, in areas where deer population density is really high, female mountain lions can have home ranges of only 17 square miles. However, when deer population density is very low, females can have home ranges of up to 500 square miles.

In contrast, the male home range size is directly dictated by female availability.

“The males will travel alone, going around and checking in on females with whom they’ve mated. They do this to make sure that their kittens are growing and carrying on their DNA, and to see if they are able to mate with those females again,” said Johnston. 

While females instinctively know which offspring is theirs, males only can identify potential offspring through recognizing female mothers they’ve mated with. If a male mates with a female 3 months prior and then sees her with kittens, he assumes they are his.

With this in mind, males make constant laps around the range of females they’ve mated with in order to check in on them and interpret their status. 

The main evolutionary drive for male mountain lions is therefore to pass on their genes, while for females it is to keep offspring alive and raise them. 

“Counting and tracking the adult females is probably therefore the most important part of studying mountain lion behavior, since everything else is based around that,” explained Johnston.  

The Eastern Sierra Interpretive Association Winter Adventure Series will host talks at the Mammoth Lakes Welcome Center every Thursday evening through March 3. The next talk is on February 17 at 7 p.m. featuring Brooke Maushund and Anika Ramey, both ski patrollers and climbers. The Talk is titled “Alone in the Mountains”, and the two speakers will describe how their love for being in the mountains has defined their lives.