According to the Coloradoan, the official necropsy report of the animal killed by Kauffman on the Fort Collins trail in Colorado estimates the lion's age to be just three-to-four months.
The necropsy, which was performed by local Colorado Parks and Wildlife vets, identified the lion as a 'kitten'.
While its weight was listed as 24 pounds, officials said the lion's weight when alive could have been 35 to 40 pounds.
Its sex could not be confirmed as some of its body parts were missing, having presumably been scavenged. However, officials do believe the animal may have been a male, as the intact pelvic area did not indicate it had had a uterus.
After telling authorities about what happened, Kauffman's story attracted much media attention across the world, not only due to the rarity or someone being attacked by a mountain lion - but also someone's ability to fend one off.
The 31-year-old explained: "It was going up towards my face so I threw up my hands to kind of block my face, at which point it grabbed onto my hand and wrist and from there it started to claw at my face and neck.
"And that's when kind of my fear response turned into more of a fight response.
"Because I'm a recent cat owner, I know that the back claws are pretty dangerous when it comes down to an attack. And I was pretty worried about its claws just sinking into my stomach and groin area.
"I was able to shift my weight and get a foot on its neck... I stepped on its neck with my right foot and just slowly after a few minutes I thought I would be getting close and then it would start thrashing again and I had a few more scratches that resulted from those thrashes at that point, and I'd say another couple minutes later it finally stopped moving."
A spokeswoman for Colorado Parks and Wildlife, Rebecca Ferrell, had said examinations of the juvenile mountain lion confirmed it had been choked. She also said Kauffman had done the right thing by fighting back, telling Buzzfeed News: "It's definitely not something you hear every day.
"We know it sounds hard to believe, but his survival instinct kicked in and he did what he had to do."