Squirrels’ acrobatic leaps across treetops depend on complex split-second calculations and inventive “parkour” maneuvers to stick tricky landings, a new study in the journal Science said Thursday.
Scientists at UC Berkeley designed obstacle courses to better understand how the rodents gauge and adjust their movements on the fly, as they dart away from predators and avoid potentially fatal falls.
The hope is that the research could one day help to build more agile robots with better decision-making skills.
“Squirrels have a combination of traits that make them very interesting: one being their acrobatic nature, their biomechanics and their powerful muscles that they can use to leap many times their body length,” lead author Nathan Hunt said.
“The other is their cognitive capabilities, they have great memories, they’re highly creative animals, and they’re really good at problem solving.”
The team used peanuts to lure wild fox squirrels on the edge of campus to their experiments.
Perches were set up to simulate tree branches, forcing the squirrels to jump gaps of varying distances in order to receive their treats. The scientists were keen to learn how the animals would negotiate a critical trade-off: Moving towards the end of a perch reduced leaping distance, but compromised stability and jumping force as the launch platform became more wobbly.
It turned out the squirrels preferred to launch from the base of the perch, particularly when the branches were bendier. In fact, the bendiness of the branch was six times more critical than the gap distance in their decision making.
Throughout the experiments, none of the squirrels ever fell, because they used a variety of strategies — and their sharp claws — to recover from imperfect landings.
If they jumped too far, they would swing over the target perch and perform a roll around it to stick the landing.
If they jumped short, they swung underneath the perch before pulling themselves up.
But the most surprising innovation came when the squirrels didn’t aim for the target branch directly at all, instead bouncing off an adjacent wall to make the most challenging leaps, akin to parkour.
When squirrels are chased by hawks, their escapes come down to a matter of centimeters, which is probably why they evolved to become so nimble, said Hunt.
While the research might one day further the field of robotics, it’s also something people can appreciate when they see squirrels in parks or in their gardens, said Hunt.
“It’s a fun thing to communicate this research because people watch squirrels in their backyard all the time. Actually, as I just sit in my backyard and watch them, I come up with other ideas for experiments that I’d like to do.”
On those rare days in Kaohsiung when the air is crisp and clear, the eastern horizon is dominated by a green wall that towers high above the Pingtung plains. This is the ridge running from Wutou Mountain (霧頭山), up to Beidawu Mountain (北大武山) at 3,092 meters. Many make the trek up to Beidawu, but very few walk the top of this wall over to Wutou, and for good reason: it is an unmarked, overgrown death trap with no reliable water and steep slopes full of rotten wood and crumbly rock. Last week, news emerged that a French couple called for rescue
One stormy night in May, Kim loaded his family into his home-made wooden boat and sailed away from North Korea, hoping to give his children a life of freedom. Tens of thousands of North Koreans have fled to South Korea since the peninsula was divided by war in the 1950s, but most go overland to neighboring China first. Defecting by sea is extremely rare and seen as far more dangerous than land routes, with only a handful of people making it across the de facto maritime border, the Northern Limit line. But Kim, a 31-year-old fisherman who asked that AFP use only his
Hitting tennis balls across a tree-lined court in Thailand’s mountainous north, Connie Chen’s weekly private training session is a luxury the Chinese national could barely afford when she lived in Shanghai. China implemented some of the world’s toughest COVID restrictions during the pandemic, putting hundreds of millions of people under prolonged lockdowns. In the aftermath, younger citizens — exhausted by grueling and unrewarding jobs — are taking flight to escape abroad. With a relatively easy process for one-year study visas, a slower pace of living and cheap living costs, Thailand’s second-largest city Chiang Mai has become a popular destination. “During the pandemic, the
Comedian Xi Diao says he knows he should avoid talking politics on stage, but sharing a family name with Chinese President Xi Jinping (習近平) makes it hard to resist. Even his name is politically sensitive, the Melbourne-based amateur comedian tells audiences, setting up a joke about a group chat on the Chinese messaging service WeChat being shut down as soon as he joined it. The 33-year-old civil engineer gets nervous laughs whenever he breaks a de facto rule of Chinese comedy: Don’t say anything that makes China look bad. To most comedians, that means no jokes about censorship, no mentioning the president’s