A mountain lion killed a man in Larimer County, Colorado on New Year’s Day 2026. The attack happened on a trail where, months earlier, the victim’s dog had been taken off-leash on the same peak. Colorado Parks and Wildlife investigators believe the dog’s earlier presence may have drawn the lion into a pattern of associating that trail with prey-sized animals.

Then in February, a mountain lion grabbed a leashed dog off a sidewalk in Glendale, California. Not a trail. A sidewalk. Broad daylight. The owner was holding the leash when it happened.

We’ve covered bears, coyotes, rattlesnakes, and moose on this site. We’ve never done a dedicated mountain lion post. That was an oversight. Lions are the predator I think about most when I’m on trail with Rocky, and 2026 has made the case that every dog hiker in the western US needs a lion plan.

Quick Reference: Mountain Lions and Trail Dogs

Factor	Detail
Where they live	16 western states, plus confirmed populations in Florida and expanding east
Weight range	80–200 lbs (males), 65–140 lbs (females)
Kill method	Bite to the base of the skull or neck. Fast. Often from behind
Your dog’s risk profile	Dogs 20–80 lbs look like ideal prey (deer-sized, four-legged, unaware)
Key difference from bears	Lions stalk silently. The first sign of a lion is often the attack itself
Best defense	Awareness, short leash, group hiking, making yourself large
2026 incidents	Fatal attack in Larimer County CO (Jan 1); leashed dog taken off sidewalk in Glendale CA (Feb)

Bottom line: Mountain lions hunt by ambush. Your dog looks like food. Unlike bears and coyotes, you probably won’t see a lion before it acts, which means prevention is the entire game.

Why Your Dog Is a Lion Magnet

This is the part that changed how I think about trail safety with Rocky.

A mountain lion’s primary prey is mule deer. Deer weigh 100 to 250 pounds. Your 40-pound trail dog falls at the low end of that prey profile, but the movement pattern is close enough. Four legs, low to the ground, moving through cover. A lion watching from a ridge doesn’t distinguish between a deer and a dog at distance. It sees prey.

Dogs between 20 and 80 pounds are the sweet spot for lion predation. Small enough to take down quickly, large enough to be worth the energy. Rocky at 50 pounds is squarely in that window, and that’s not a comfortable thought.

But size isn’t the only factor. Dogs do things that trigger predatory behavior in cats. They run ahead on the trail, investigate brush, put distance between themselves and their handler. Every one of those behaviors looks like a prey animal separating from a herd.

Colorado Parks and Wildlife issued formal guidance after the January 2026 attack citing dogs as a lion-attractant factor. A dog’s scent, waste, and movement on a trail can draw a lion’s attention to that corridor. The Larimer County case may be an example of exactly this pattern — a dog running off-leash on a peak, a lion registering that activity, and a fatal encounter months later on the same trail.

How Mountain Lions Hunt (And Why That Matters for Dogs)

Mountain lions are ambush predators. Full stop. They don’t charge across an open meadow like a bear. They don’t lure prey away from a group like a coyote. They sit. They watch. They close distance using terrain and cover. Then they strike from behind.

The kill method is a bite to the base of the skull or the back of the neck. It’s designed to sever the spinal cord. On a deer, this happens after a short rush from concealment — usually from above or behind. On a dog, it can happen the same way.

Here’s what makes this different from every other wildlife encounter I prepare for: you may not get a warning. With bears, you usually see them or your dog alerts. With coyotes, they approach visibly and test boundaries. A mountain lion’s entire strategy is to not be seen until it’s too late.

Rocky has solid wildlife awareness. He’s alerted me to bears, coyotes, and elk before I spotted them. But a lion using terrain cover and approaching from behind? I don’t count on any dog catching that in time.

What the 2026 Attack Cluster Tells Us

Two incidents in two months, and they tell different stories.

Larimer County, Colorado — January 1, 2026. A man was killed by a mountain lion while hiking. The trail had a history — his dog had been taken off-leash on the same peak months before. Colorado Parks and Wildlife investigators connected the dots: a dog running free in lion habitat can create a pattern where the lion begins associating that area with accessible prey. The lion may have been habituated to dog activity on that trail before the fatal encounter. The Colorado Sun reported on the investigation and the off-leash connection.

Glendale, California — February 2026. A mountain lion snatched a leashed dog from a sidewalk while the owner held the other end of the leash. This wasn’t backcountry. This was a suburb abutting the Verdugo Mountains. Hoodline covered the incident, noting the lion’s boldness in an urban-adjacent setting.

The Larimer County case is about habitat overlap and conditioning. The Glendale case is about urban-wildland interface and lions losing their wariness of human spaces. Both are relevant if you hike with a dog anywhere in lion range.

What to Do If You See a Mountain Lion

Most people who hike in lion country never see one. I’ve logged over a thousand miles with Rocky across Colorado, Arizona, and New Mexico and I’ve seen a mountain lion exactly once — a tan shape moving through scrub oak above the trail in the Wet Mountains. It was gone in seconds. Rocky never reacted, which tells me the lion was already watching us and chose to leave.

But if you do see one, and it hasn’t fled:

1. Do not run. Running triggers pursuit. This is a cat. Cats chase things that run.
2. Do not crouch or bend down. You want to look as large and tall as possible. Crouching makes you look like prey.
3. Face the lion. Mountain lions attack from behind. Facing them removes their preferred angle.
4. Make yourself big. Open your jacket wide, raise your arms, raise trekking poles overhead. You want to look like something that’s more trouble than it’s worth.
5. Pick up small dogs immediately. If your dog is under 30 pounds, get them off the ground and into your arms. A small dog on the ground is an easy target.
6. Keep larger dogs close. Shorten the leash to your hip. Don’t let them lunge toward the lion.
7. Talk loudly and firmly. Deep, aggressive voice. Not screaming. Commanding.
8. Back away slowly. Maintain eye contact. Don’t turn around. Give the lion space to retreat.
9. If the lion approaches or crouches: Throw rocks, sticks, water bottles — anything. Yell. Make it clear that engaging you has a cost.
10. If it attacks: Fight back. Hard. Go for the eyes and nose. Use trekking poles, a knife, bear spray, rocks, whatever you have. Unlike grizzly encounters, playing dead does not work with mountain lions. A lion attacking a human is treating you as prey, and prey that fights back often survives.

The Off-Leash Problem in Lion Country

I support off-leash hiking for trained dogs in the right conditions. I’ve written about building that reliability. But lion country changes the calculation.

An off-leash dog does two dangerous things in lion habitat. First, it ranges ahead into cover where a lion may be concealed — putting itself within ambush distance without you nearby. Second, if the dog spots the lion and bolts back to you, it can bring a pursuing cat directly to your position. Same problem as bears.

The Larimer County case specifically involved off-leash dog activity on the same trail where the fatal attack occurred. I’m not saying the off-leash excursion caused the attack — correlation isn’t causation. But CPW cited it as a contributing factor in the lion’s behavior pattern.

Rocky stays leashed in confirmed lion habitat. Period. A 6-foot leash, short enough to keep him at my side. I don’t run a long line where I can’t see 50 yards in every direction.

Building Your Lion Country Protocol

Here’s what Rocky and I run in known mountain lion habitat across Colorado’s Front Range and the desert Southwest.

Before the hike:

• Check with local wildlife agencies for recent lion sightings or activity. Colorado Parks and Wildlife maintains a lion sighting map and activity reports
• Hike in groups when possible. Lions target lone individuals and single dogs. Two or more people significantly reduce attack probability
• Leash up. No exceptions in lion habitat
• Carry bear spray — it works on mountain lions at close range. Hip holster, same as bear country
• Avoid dawn, dusk, and night. Lions are crepuscular hunters. Peak activity is low light. I schedule my hikes for mid-morning through mid-afternoon in heavy lion country

On the trail:

• Stay on open, maintained trails with good sight lines. Lions use cover — brush, rock outcroppings, ledges above the trail. The more open the terrain, the fewer ambush opportunities
• Don’t let your dog investigate brush piles, rock piles, or dark overhangs. These are exactly the concealment a lion uses
• Watch for signs: deer carcasses (especially covered with debris — lions cache kills under leaves and dirt), large cat tracks (round, 3+ inches, no claw marks unlike canids), scrapes and scat
• If Rocky goes rigid and stares into cover without barking, I take it seriously. That’s his alert posture. We stop, scan, and if I can’t explain what he’s seeing, we back out
• Keep children and small dogs between adults. Lions target the smallest, most separated member of a group

If a lion takes your dog:

This is the scenario nobody wants to think about. A lion can grab a dog and disappear into cover in seconds. If it happens:

• Do not chase into dense brush. You’re entering a predator’s chosen terrain on its terms
• Make as much noise as possible. Lions sometimes release prey when confronted aggressively
• Call 911 and your state wildlife agency immediately
• If you have a GPS collar on your dog, it becomes critical in this moment. It’s the only way to track where the lion has gone

The Gear That Matters in Lion Country

You don’t need specialized mountain lion gear. You need the same kit that works for bear country, deployed differently.

Bear spray. Same stuff, same hip holster. A lion at close range gets the same treatment as a charging bear. Counter Assault and UDAP both work.

Trekking poles. In lion country, these aren’t just for balance. Raised overhead, they make you look taller. Jabbed forward, they create distance. They’re a weapon if things go bad.

A short, fixed leash. Not a bungee, not a retractable, not a long line. Four to six feet of fixed webbing that keeps your dog at your hip with no slack for them to range into trouble.

A harness with a grab handle. If you need to physically hold Rocky back or pull him close in a split second, the back handle on his harness is how that happens.

A headlamp with a strobe function. If you’re caught on trail at dusk (it happens, even when you plan for midday hikes), the strobe may deter an approaching lion. Cats don’t like unpredictable light.

Don’t Skip the Mountains. Just See Them Clearly.

I’m not here to scare you off lion country. Some of the best hiking on the continent — the Colorado Rockies, the Sierra Nevada, the Cascades, the Arizona sky islands — is lion habitat. Rocky and I hike in it regularly. We’ll keep hiking in it.

But mountain lions demand a different kind of respect than bears or coyotes. You can haze a coyote. You can make noise for bears. A lion doesn’t give you those opportunities. Its entire strategy is to act before you can react.

The 2026 incidents are a reminder that this predator is present, active, and occasionally targeting dogs specifically. The Larimer County fatality started with an off-leash dog. The Glendale grab happened on a sidewalk. Neither victim was doing anything reckless by most people’s standards.

What you can control: leash discipline, group size, timing, terrain awareness, and carrying deterrents. That’s the margin between hiking in lion country and hiking safely in lion country.

Rocky and I have a trip into the Sangre de Cristos planned for April. He’ll be on a short leash. I’ll have bear spray on my hip. We’ll be on trail by 9 AM and off by 3 PM. And I’ll be watching the ridgelines the way I watch meadow edges for coyotes — not with fear, but with the kind of attention that keeps us both coming home.

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Field observations from hiking with Rocky (50 lb Australian Shepherd mix) across Colorado, Arizona, and New Mexico, 2022–2026. 2026 incident details sourced from Colorado Sun (Larimer County) and Hoodline (Glendale, CA). Post-attack guidance from Colorado Parks and Wildlife, January 2026. Mountain lion behavior and safety protocols referenced from CPW and California Department of Fish and Wildlife. Always check local wildlife agency reports before hiking in lion country.