Those sightings are quite old in comparison to the active case you referenced. When you say biker are you talking about a bicyclist (a cyclist) or a motorcycle/dirt bike (biker)? I have never heard of a mountain lion attacking someone on a motorized vehicle but if you have a link, I'd like to see it.
I understand and respect that everyone has their theories and their opinions and not everyone will agree. However, with that said I think that there should be some caution when suggesting any idea, theory, or opinion as fact. BBM above are several very definitive statements that have been made about the way mountain lions kill. I don't want to seem like I'm picking on anyone but I've been biting my tongue for some time on this and wanted to share some info.
Can they kill instantly and silently? Sure. Do they always? Absolutely not. In this link:
http://www.aws.vcn.com/mountain_lion_fact_sheet.html
that others have referenced as well, you can note a few things if you scroll down to the part titled
"
Here are a few documented mountain lion attacks on humans"
In particular:
1. While the approach and initial attack may be silent and even not witnessed, the attack itself is often not silent or instant.
2. The neck is often a target for an attack on larger prey, sure, but think about this in terms of a toddler. Have you ever tried finding a toddler's neck even to tickle or kiss? They barely have a neck and if they do, it's tiny! You will see in the cases cited that most attacks on toddlers and young children don't involve the neck at all. A lion's mouth wouldn't fit and because they are opportunistic, they grab what is easiest for control. Absent an available neck, they grab heads and faces. This results in an attack that is neither silent nor instant.
3. Mountain lions may drag their prey away but even in the fatal Montana case that is referenced, they don't take it miles. In that case, they consumed the boy right near his home. They typically drag it to an area that is more private/covered, into brush, or just off the trail where an attack occurs. Also, note that even in the case of very small children, they are often dragged, not carried off the ground. If you think about how tall a lion is and how long a young, lifeless body would be (especially one being grasped by the head), there would be some dragging involved, even if it is just toes trailing. I know these are awful thoughts but they should be considered if we want to spend time on this as a possibility.
I believe if an attack occurred that the kill would have been discovered. I have been unable to find documentation of kills being carried or dragged for miles, only feet and yards.
http://balancedecology.org/mountainlionwebsite/Mountain_Lion_Behavior.html
"Behavior with Kill
After making a kill, the Mountain Lion will usually drag the kill to a protected area and feed on the shoulder and upper abdomen areas first. If cubs are present, they will feed on soft tissues before continuing to consume other body parts.
After feeding, Mountain Lions separate the internal organs from the main carcass and hide them at a distance before covering both with branches, soil, and leaves. Mountain Lions do not dig holes in order to bury their kills. They will behave with carcasses they scavenge on in the same way they behave with a kill.
Mountain Lions will return to the kill repeatedly until the meat is gone or, especially during the summer, until the meat has spoiled, at which time they will hunt again. As long as the meat is fresh, a Mountain Lion is taken out of the hunting cycle and will not kill. It is unclear how many and how often a Mountain Lion may kill large and small prey. Being opportunistic, Mountain Lions are able to switch their prey based on abundance and availability."
http://mdc.mo.gov/discover-nature/wildlife-reporting/mountain-lion-reports/mountain-lion-signs
"Kill Evidence
Mountain lionsThey generally kill their prey quickly and efficiently. They creep close, then rush quickly to hit the animal and bite it either in the back of the neck to sever the spinal column, the throat to crush the trachea, or the skull to puncture the brain. They do not have long endurance, and do not make long chases.
Mountain lions use their claws primarily as hooks to hold onto their prey until they can administer a lethal bite. They seldom leave deep slashes.
After the prey is dead, they generally drag the carcass to dense cover to feed. They often open the abdominal cavity, roll out the stomach and intestines and begin feeding on the other soft internal organs. On other occasions they begin to feed at the shoulders and ribs.
After theyve eaten their fill, mountain lions generally cover the remainder of the carcass with grass, leaves, dirt and other debris. They return to the kill for subsequent feedings as long as it lasts, or until they make another kill."
A point that was mentioned was that there might not be any trace at all left after a lion fully consumed him. Perhaps, if the lion was undisturbed, but I don't believe that the lion would have had time before being interrupted by the early search attempts. If the lion did retreat and even if it took the body with it as it left, I would think that there would be evidence left at the initial feed site. I base that opinion on the gruesome way a lion eats (see above).
I further believe that even if nothing was left at the feeding site, the blood and such that would inevitably remain would attract flies and that would be noticed. BBM
http://www.cbc.ca/m/touch/world/story/1.3085910
"Trekking through the dense bush in California's Santa Cruz mountains, field biologist Justine Smith is full of helpful tips.
Like this one: if you're searching for a hidden carcass and can't smell it, just listen.
"You can hear the flies around the carcass," Smith explains.
Smith is a doctoral student and researcher at the University of California, Santa Cruz. She and her colleagues at the Santa Cruz Puma Project are trying to figure out what impact people and the nearby roads are having on the mountain lions, which are also known as cougars or pumas. Humans may be setting the protected species on a slow, quiet path to extinction."
Another reason why I question the possibility of a lion being responsible is that many studies have shown that lions avoid wolves for a very good reason. Wolves kill mountain lions and we know a pack of wolves were in the area.
http://voices.nationalgeographic.com/2013/12/04/hunters-or-hunted-wolves-vs-mountain-lions/
"In fact, wolves kill mountain lions. This has never been disputed. Wolves are considered the dominant competitors in most interactions between the species. Take for instance, the Hornocker Institute study of mountain lions in Northern Yellowstone led by Dr. Toni Ruth, in which researchers discovered the remains of three mountain lions killed by wolves. What is contentious is the idea that mountain lions might kill wolves."
I'm not saying that an animal attack (or scavenging activity) was impossible but let's use supported facts and not assumptions and opinions if we want to explore it as an option. Mountain lions can be scary but they are just animals. They aren't supernatural in any way. I live, work, hike, camp and play in country that is home to mountain lions, wolves, grizzlies, black bears, coyotes, lynx, bobcats and any other North American critter you can think of. They are certainly to be respected and attacks do happen but I honestly feel that I am in more danger behind the wheel when I drive to the campsites and trail heads that I go to than I am just hanging around camp, even if I was wearing a Lady Gaga meat dress.
(Trying to lighten the mood after my gruesome and long post).
