Cute but cunning, yellow-bellied marmots are wreaking havoc on hikers and campers in California’s Sequoia National Park, stealing shoes and backpacks, chewing through gear and even disabling vehicles.The ground squirrels, which can grow as large as small dogs, are a notorious nuisance in Mineral King Valley. The National Park Service even warns visitors entering the remote, 7,800-foot-high area: “You are entering Marmot Country.”Marmots are common in Sequoia and Kings Canyon National Parks, especially at higher elevations. But their mischievous streak peaks from May to mid-July, when they swarm trailheads and parking lots seeking food and salt.For hikers, encounters can be startling. Andrew Reinhart, a 28-year-old engineer from Livermore, California, woke from a nap after a mountain hike last month to find a marmot’s wet tongue in his ear. “It scared the s*** out of me,” Reinhart told the Wall Street Journal. “You don't expect to get licked when you go to sleep in the woods.”Marmots in California’s Mineral King Valley are especially troublemakers during peak season, from May to mid-July (NPS/Walt Kaesler)Other hikers have lost gear. Jeff Weit, 66, now ties his shoes together after a marmot previously stole one. He later spotted the animal peeking at him from behind a log.“I reached underneath the log, and there was my shoe!” Weit told the WSJ. “You have to treat your shoes like bear food.”Nitin Gupta, 31, said a large marmot once stole his hiking pole and charged his girlfriend when she tried to take it back.“I heard this almost war cry,” Gupta said. The hikers eventually gave up the pole.The bigger concern, however, comes when hikers return to their cars.Park visitors are urged to wrap their cars in plastic tarps to keep marmots from getting underneath, where they can chew plastic, radiator hoses, brake lines and electrical wires (National Park Service/Jennifer Swacina)Marmots can crawl under vehicles and into engine compartments, chewing radiator hoses and electrical wiring and drinking fluids. The damage can leave cars stranded in the remote park. One hiker featured in the WSJ had to pay more than $1,000 for a tow after a marmot damaged his vehicle.The animals’ attraction to salt may explain some of their behavior. UCLA marmot expert Dan Blumstein said they seek salt on sweat-stained backpack straps and hiking poles and are also drawn to fluids and materials around vehicles.For years, visitors used chicken wire to protect their cars, but marmots learned to get around it. The NPS now recommends a more unusual defense: wrapping vehicles in plastic tarps.Visitors can drive over a tarp and wrap it around the vehicle, including the wheel wells, to keep marmots from crawling underneath. The NPS also recommends checking vehicles for damage and inspecting under the hood before starting the engine.Marmots are large, stout ground squirrels and among the heaviest rodents in the world (AP)The marmot threat appears to have eased, though the park did not keep an official tally of vehicle damage, the WSJ reports. With peak season over, officials say tarping is no longer necessary, but Samantha Weldon, manager of the Silver City resort, still recommends it for multiday hikes.“The risk is lower, but it’s never gone,” Weldon, who once found herself in a tug-of-war with a marmot over her backpack, told the outlet.California is not the only place dealing with unruly marmots. One Colorado marmot, nicknamed “Fork Kardashian,” famously sneaked into a vehicle and ended up in Arizona before researchers flew it back home, Dan Blumstein, a marmot expert from the University of California, said.Last winter, two-thirds of a Colorado marmot population died during hibernation due to insufficient snow cover. Survivors are now fattening up for winter and starring in the first-ever Fat Marmot Week, an online contest modeled after Fat Bear Week that started Monday and also raises money for marmot research.