Nancy Howard, Colorado Parks & Wildlife
Nancy Howard, Colorado Parks & Wildlife

Training Mountain Lions to Walk on Treadmills (for Science!)

Nancy Howard, Colorado Parks & Wildlife
Nancy Howard, Colorado Parks & Wildlife

Cat owners everywhere know how hard it is to get their felines to do something when they don't want to. Now imagine your cat is 5 feet long and 135 pounds, and you’ll understand the challenge University of California Santa Cruz's Terrie Williams faced when she decided to measure the energetics—or flow and transformation of energy—in mountain lions, which required getting the big cats to walk on a treadmill. “It’s one of those things that you put into a grant proposal and hope you can pull off,” the professor of ecology and evolutionary biology says. “There’s a reason why mountain lions and jaguars and leopards are not generally in shows—it's because they're impracticable. I got ulcers over that part of it.”

Williams, who has been studying animal energetics for most of her career, had always wanted to work with big cats; mountain lions were the natural choice because of their proximity. “They’re right in our backyard,” she says. “We had a young mountain lion come down near the lab—it was pouncing on a glass door because it saw its reflection!"

Knowing mountain lion energetics (or any other big predator's energetics) is important because it helps scientists see how many calories a population needs to survive and ensure future generations, which in turn helps conservationists and ecologists make wildlife management and planning decisions. "If you want to have big, charismatic predators around, you better know what they need to eat,” Williams says. “If you don’t pay attention to that, you start to see more and more human/animal conflict.”

In humans, scientists measure energetics by putting people on treadmills with special instruments that measure how many calories they expend, so Williams would have to do the same thing with mountain lions—not just get them on treadmills, but also outfit them with the team’s custom-built collars that included radio and satellite tracking as well as an accelerometer, which “allowed us to calibrate the collar both for behavior and energetics,” Williams says. Big cat experts told her that that would be tough to do, too: "Most facilities told me, ‘You can’t put on a collar!’ I was like, ‘Great.’”

Still, Williams was determined to do the research; it took her three years to find a facility that was game to try. She found Lisa Wolfe, a veterinarian with Colorado Parks and Wildlife, through a friend; Wolfe had raised three mountain lions from the time they were kittens after their mother had been shot. “I didn’t even want to tell her about the treadmill,” Williams said. “I just said, ‘Can we put a collar on your cats?’”

Photo by T.M. Williams

Thankfully, Wolfe had no difficulty getting the collars on—it took all of five minutes—so all that was left to conquer was the treadmill, which the veterinarian also had on hand. Getting the cats on that took a little longer, though: Wolfe worked with the cats for 10 months. “The hard thing about cats on treadmills—even domestic cats—is getting them to face forward,” Williams says. “They don’t do well on treadmills because they look at their feet. Dogs will look at you, canids will look up, but cats will want to see where their feet are going on a treadmill, so their head goes down and then they trip and fall and it’s a mess.” To keep the cats facing forward and walking naturally, Wolfe used meat, feeding the animals as they were walking.

There were a number of engineering challenges, too, to get the treadmills ready for the cats. “The hardest part was the sounds—mountain lions are really intoned to sounds, so I had to be very careful with the instrumentation in the vacuum pumps,” Williams says. “And that really took the longest time.” Plus, Wolfe’s treadmill, intended for humans, was too short—the cats ended up with their back two feet off the treadmill and their front two feet walking on the belt—so the researchers got a dog treadmill with an 8.5-foot surface. Then they built a clear metabolic box around the treadmill so they could accurately measure oxygen consumption, taking into account not just the length of the animals’ bodies, but their tails, too. “The box had to be big,” Williams says. You can see the cats strutting their stuff in the video below:

Williams and Wolfe had the animals sit in the box at rest, then had them walk, trot, and run while wearing the collars. “We didn’t do a lot of running, because when we did the tests with the collars, just with the animals in the enclosures, we decided to stick with what the animals did routinely and not force them to do these high energy things, which we found even for the wild animals, really isn’t their style,” Williams says. “Their style is a stalk and pounce. They walk around a lot, pretty slowly. They’re not fast movers unless they’re being chased or chasing something.”

From collaring the captive cats and making them walk on treadmills, as well as videotaping their behavior in their enclosures, Williams and her colleagues were able to learn how many calories the cats expended for every step they took, whether they were going uphill, downhill, resting, hunting, eating, or drinking—basically, any behavior you can think of. “We had this library that had the signature on the accelerometer, the assigned behavior that goes with it, and how many calories the animals had to expend for that behavior,” Williams says. “Then you multiply that by the time they spend doing each one of those behaviors each day, and suddenly, you know the when and where of how they’re making a living. Like a diary.”

In the background of this illustration are typical SMART collar accelerometer traces for walking and then running, while the foreground shows a collared puma chasing a black-tailed deer. (Image by Corlis Schneider)

That gave them a base that they could apply to the five wild mountain lions they collared and tracked. Williams and her team decided to examine the most energetically expensive part of the day: The two-hour hunt and kill. “What we found was that the more they can sit and wait, or the more they can stalk as opposed to running around the country-side looking for things, the cheaper it is for them,” Williams says. “They get more calories for a prey item, relative to what they expended to get it, if they can do this normal, cryptic behavior. If you make these cats walk more to try and find food, the harder it’s going to be for them.”

They also discovered that wild cats use more calories than captive cats. “We were off about two and half times when it came to what we measured versus what had been predicted for energetic costs,” Williams says. “It makes sense. Think of yourself on a treadmill, and then think about how many calories you spend when you’re running around a trail. It’s those ups and down and twists and turns and rights and lefts that you’re doing that cost you. For us, we get to lose weight, but for the cats, it’s a tougher way to make a living.” Habitat depletion, either by human development or causes like fires, means more walking for mountain lions.

The SMART collar technology not only helps scientists better understand what these mostly hidden animals are doing, but also help come up with strategies to save them. “People want to think that these animals just don’t need that much—it keeps them less fierce—but we need to face the reality that it takes a lot be a carnivore,” she says. “[Tracking gives us the] ability to create wildlife maps that are based on biology of the animals, as opposed to looking at a map and saying ‘mountain lions belong here.’ You’re now able to say that animals are able to thrive in a particular area, that there’s plenty of food for them, and the result is fewer animal-human conflicts. I feel it’s a whole new way of doing conservation.”

Kerry Hayes, Warner Bros. Entertainment Inc. and Legendary Pictures
10 Monster Facts About Pacific Rim
Kerry Hayes, Warner Bros. Entertainment Inc. and Legendary Pictures
Kerry Hayes, Warner Bros. Entertainment Inc. and Legendary Pictures

Legendary Pictures took a gamble on Pacific Rim, Guillermo del Toro’s 2013 monster/robot slugfest. Since it wasn’t based on a preexisting franchise, it lacked a built-in fanbase. That can be a serious drawback in our current age of blockbuster remakes and reboots. The movie underperformed domestically; in America, it grossed just over $100 million against its $180 million budget. Yet Pacific Rim was a huge hit overseas and acquired enough fans to earn itself a sequel, Pacific Rim Uprising, which arrives in theaters this week. Here are 10 things you might not have known about the movie that started it all.


Idris Elba in 'Pacific Rim' (2013)
Warner Bros.

One foggy day in 2007, Beacham—who’d recently moved to California—was walking along Santa Monica Beach. As he looked out at the Ferris wheel on the city’s eponymous pier, he pictured a looming sea monster. Then he imagined an equally large robot gearing up to fight the beast. “They just sort of materialized out of the fog, these vast godlike things,” Beacham said. He decided to pursue the concept further after coming up with the idea of human co-pilots who’d need to operate their robot as a team, which added a new thematic dimension.

“I didn’t know I had something I wanted to write until I realized these robots are driven by two pilots, and what happens when one of those people dies? What happens to the leftovers? Then it became a story about loss, moving on after loss, and dealing with survivor’s guilt," Beacham said. "That made the monsters scarier because now you care about the people who are in these robots.”


Pacific Rim was picked up by Legendary Pictures and handed over to director Guillermo del Toro. A huge fan of monster cinema, del Toro enthusiastically co-wrote the final screenplay with Beacham. Sixteen concept artists were hired to sketch original robot and creature designs for the film. “We would get together every day like kids and draw all day,” del Toro told the New York Daily News. “We designed about a hundred Kaijus and about a hundred Jaegers and every week we would do an American Idol and we would vote [some of] them out.”


In “Charlie Kelly: King of the Rats,” the tenth episode of It's Always Sunny in Philadelphia's sixth season, Charlie Day’s character gives us a darkly comedic monologue about rodent extermination. Little did the actor know that the performance would open a big opportunity for him. Impressed by the rat speech, del Toro offered Day the part of Dr. Newton Geizler, Pacific Rim’s socially-inept kaiju expert. “He said to himself, ‘That’s my guy. That guy should be in my next movie because if he killed rats, he can kill the monster,’” Day recalled during an appearance on Late Night with Jimmy Fallon. On the movie set, del Toro often joked about how much he enjoys It’s Always Sunny. As a way of repaying his director, Day helped get del Toro a minor role in the series.


Most of the film’s special effects were computer-generated, but not everything was digital. For the robot cockpit scenes, del Toro had his team build the interior of a full-scale Jaeger head. The finished product stood four stories tall and weighed 20 tons. And like a Tilt-A-Whirl from hell, it was designed to rock around violently on its platform via a network of hydraulics. Once inside, the actors were forced to don 40-pound suits of armor. Then the crew strapped their feet into an apparatus that Charlie Hunnam has compared to a high-resistance elliptical machine.

Certain shots also required del Toro to dump gallons of water all over his exhausted, physically-strained stars. So yeah, the experience wasn’t much fun. “We saw every one of the actors break down on that set except for the female lead actress Rinko Kikuchi," del Toro said. "She’s the only actor that didn’t snap."


Del Toro wanted Gipsy Danger, his ‘bot, to have the self-confident air of a wild west gunslinger. To that end, he and concept artist Oscar Chichoni developed a swaggering gait that was based on John Wayne’s signature hip movements. The Jaeger’s Art Deco-like design was influenced by the Chrysler and Empire State Buildings.


Hailed as the “fortieth greatest guitarist of all time” by Rolling Stone, Rage Against the Machine's Tom Morello rocked the MTV generation with hits like “Bulls on Parade” and “Killing in the Name.” Pacific Rim bears his mark as well. The film’s lead composer was Ramin Djawadi, whose other works include the Game of Thrones theme. Wanting to add a “rock element” to the Pacific Rim soundtrack, he and del Toro reached out to Morello. The guitarist didn’t need much persuading.

“When they asked me to put some giant robot riffs and screaming underwater monster licks on the film score, I was all in,” Morello said. Djwadi was pleased with the rocker's contributions to the project. As he told the press: “Tom’s unique style and sounds really defined our robots.”


A definite highlight of this movie is Gipsy Danger’s duel with the winged kaiju Otachi in downtown Hong Kong. Both characters were computer-generated, as were the majority of the streets, cars, and towers in this epic sequence. However, there is one moment which was at least partly realized with practical effects. Gipsy punches through the wall of an office building early in the fight. We see her fist rip through a series of cubicles and gradually decelerate until it lightly taps a chair with just enough force to set off a Newton’s Cradle desktop toy. For that shot, effects artists at 32Ten Studios constructed a miniature office building interior featuring 1/4-scale desks, cubicles, and padded chairs. The level of detail here was amazing: 32Ten’s staff adorned each individual workspace with lamps, computers, wastebaskets, and teeny, tiny Post-it notes.


Rinko Kikuchi in 'Pacific Rim' (2013)
Kerry Hayes, Warner Bros. Entertainment Inc. and Legendary Pictures

Audiences reacted strongly to Kikuchi’s character Mako Mori, who inspired an alternative to the famous Bechdel test. Some critics praised the culmination of her relationship with Raleigh Beckett (Hunnam). Although it’s common practice for the male and female leads in an action flick to end their movie with a smooch, Mori and Beckett share a platonic hug as Pacific Rim draws to a close. Del Toro revealed that he shot three different versions of that final scene. “We did one version where they kiss and it almost felt weird. They’re good friends, they’re pals, good colleagues,” del Toro said.


At the end of the credits, there’s a tribute that reads: “This film is dedicated to the memories of monster masters Ray Harryhausen and Ishiro Honda.” Harryhausen passed away on May 7, 2013—two months before Pacific Rim’s release. A great stop-motion animator, he breathed life into such creatures as the towering Rhedosaurus in 1953’s The Beast From 20,000 Fathoms.

Ishiro Honda was another giant of the kaiju genre, having directed Rodan, War of the Gargantuas, and numerous Godzilla films. Del Toro has great respect for both men. When Harryhausen died, the director said, “I lost a member of my family today, a man who was as present in my childhood as any of my relatives.” He also adores the Japanese monster classics and says he’d love to see a Pacific Rim-Godzilla crossover someday. Maybe it’ll happen.


If you’re not familiar with the practice of “Sweding,” let us fill you in: The 2008 comedy Be Kind, Rewind is about two co-workers at a VHS rental store who accidentally erase every tape in stock. Hoping to save their skins, they create ultra low-budget remakes of all the films they’ve destroyed using cardboard sets and cheap costumes. It’s a process these guys call “Sweding” as a ploy to convince everyone that their (unintentionally hilarious) knockoffs were produced in Sweden. Since Be Kind, Rewind was released, Sweding has become a legitimate art form.

When Pacific Rim’s first trailer debuted in 2013, YouTubers Brian Harley and Brodie Mash created a shot-for-shot, Sweded duplicate of the preview. Instead of state-of-the-art CG effects, their version used toy helicopters, duct-tape monster masks, and an ocean of packing peanuts—and del Toro loved it. At WonderCon 2013, he praised the video, saying that it inspired the editing used in Pacific Rim’s third trailer. Harley and Mash happened to be at the same gathering. When del Toro met the comedic duo, he exclaimed “I loved it! My daughters loved it, we watched it a bunch of times!” Then he invited the Sweding duo to attend Pacific Rim’s premiere in Hollywood.

Composite by Mental Floss. Illustrations, iStock.
The DEA Crackdown on Thomas Jefferson's Poppy Plants
Composite by Mental Floss. Illustrations, iStock.
Composite by Mental Floss. Illustrations, iStock.

The bloom has come off Papaver somniferum in recent years, as the innocuous-looking plant has come under new scrutiny for its role as a building block in many pain-blunting opiates—and, by association, the opioid epidemic. That this 3-foot-tall plant harbors a pod that can be crushed and mixed with water to produce a euphoric high has resulted in a stigma regarding its growth. Not even gardens honoring our nation's Founding Fathers are exempt, which is how the estate of Thomas Jefferson once found itself in a bizarre dialogue with the Drug Enforcement Administration (DEA) over its poppy plants and whether the gift shop clerks were becoming inadvertent drug dealers.

Jefferson, the nation's third president, was an avowed horticulturist. He spent years tending to vegetable and flower gardens, recording the fates of more than 300 varieties of 90 different plants in meticulous detail. At Monticello, his Charlottesville, Virginia plantation, Jefferson devoted much of his free time to his sprawling soil. Among the vast selection of plants were several poppies, including the much-maligned Papaver somniferum.

The front view of Thomas Jefferson's Monticello estate
Thomas Jefferson's Monticello estate.

"He was growing them for ornamental purposes,” Peggy Cornett, Monticello’s historic gardener and curator of plants, tells Mental Floss. “It was very common in early American gardens, early Colonial gardens. Poppies are annuals and come up easily.”

Following Jefferson’s death in 1826, the flower garden at Monticello was largely abandoned, and his estate was sold off to help repay the debts he had left behind. Around 115 years later, the Garden Club of Virginia began to restore the plot with the help of Jefferson’s own sketches of his flower borders and some highly resilient bulbs.

In 1987, Monticello’s caretakers opened the Thomas Jefferson Center for Historic Plants, complete with a greenhouse, garden, and retail store. The aim was to educate period-accurate gardeners and sell rare seeds to help populate their efforts. Papaver somniferum was among the offerings.

This didn’t appear to be of concern to anyone until 1991, when local reporters began to obsess over narcotics tips following a drug bust at the University of Virginia. Suddenly, the Center for Historic Plants was fielding queries about the “opium poppies” in residence at Monticello.

The Center had never tried to hide it. “We had labels on all the plants,” says Cornett, who has worked at Monticello since 1983 and remembers the ensuing political scuffle. “We didn’t grow them at the Center. We just collected and sold the seeds that came from Monticello.”

At the time, the legality of growing the poppy was frustratingly vague for the Center’s governing board, who tried repeatedly to get clarification on whether they were breaking the law. A representative for the U.S. Department of Agriculture saw no issue with it, but couldn’t cite a specific law exempting the Center. The Office of the Attorney General in Virginia had no answer. It seemed as though no authority wanted to commit to a decision.

Eventually, the board called the DEA and insisted on instructions. Despite the ubiquity of the seeds—they can spring up anywhere, anytime—the DEA felt the Jefferson estate was playing with fire. Though they were not a clandestine opium den, they elected to take action in June of 1991.

“We pulled up the plants," Cornett says. “And we stopped selling the seeds, too.”

Today, Papaver somniferum is no longer in residence at Monticello, and its legal status is still murky at best. (While seeds can be sold and planting them should not typically land gardeners in trouble, opium poppy is a Schedule II drug and growing it is actually illegal—whether or not it's for the express purpose of making heroin or other drugs.) The Center does grow other plants in the Papaver genus, all of which have varying and usually low levels of opium.

As for Jefferson himself: While he may not have crushed his poppies personally, he did benefit from the plant’s medicinal effects. His personal physician, Robley Dunglison, prescribed laudanum, a tincture of opium, for recurring gastric issues. Jefferson took it until the day prior to his death, when he rejected another dose and told Dunglison, “No, doctor, nothing more.”


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