Nav: Home

Leaping lizards!

June 27, 2017

RIVERSIDE, Calif. - Many geckos inhabit trees, often living high in the canopy. Relying on their incredible adhesive strength to help them break their fall, they jump from trees, and land on either leaves or relatively smooth tree trunks. How they withstand these impacts and what forces are imposed on the toepads of such falling/jumping geckos is not well understood, and could be critical to understanding the phenomenal adhesive power that these lizards exhibit.

A team of researchers led by a biologist at the University of California, Riverside now reports in the Royal Society Interface journal that the gecko adhesive system may reach its functional limits in extreme situations, such as when a gecko--seeking, for example, to escape a predator-- falls/jumps from the canopy of a rainforest.

"We found that the size of the gecko and the size of the leaf determine impact forces," said Timothy Higham, an associate professor of biology at UC Riverside, who led the research project. "In contrast to previous research that suggests that gecko frictional adhesive capacity is excessive relative to the body mass that it supports while at rest or running up a vertical surface, we show that realistic conditions in nature may result in the gecko's frictional capacity being pushed to its limit. Geckos, we found, are subjected to impact forces that approach or exceed the safety factor of a single foot, leading to the possibility of injury or a failed landing attempt."

Higham and two other scientists on the project--Anthony P. Russell, University of Calgary, Canada, and Karl J. Niklas, Cornell University, NY-- developed a modeling framework to assess whether geckos' adhesive capacity ever reaches a limit in nature. They based this upon published observations of aerial descents of canopy-dwelling geckos that are interrupted mid-fall when the geckos cling to leaf surfaces.

"Many geckos catch themselves mid-fall, by sticking to a leaf as they plummet earthwards, suggesting that the rapid deceleration that they experience might provide the selective force that is responsible for driving their strong adhesive capacity," Higham said. "This study, therefore, could provide insight into the evolution of adhesion - a topic not fully understood."

The researchers used published observations of geckos in their natural habitat in the Amazon region. In the lab, they took measurements of frictional adhesive capability. They also estimated aerodynamic forces, maximum impact forces, and subsequent loading on the adhesive system upon impact for the geckos.

Higham noted that in their experiments, he and his colleagues assumed the gecko stops immediately following impact with the leaf surface.

"However, it is likely that it could slide along the leaf surface following impact, which would reduce the impact force experienced," he said. "While it's true that landing on plant surfaces following escape-induced jumps can result in very high impact forces that challenge adhesive capacity, these can be mitigated by the bending of the leaf and/or stem."

According to Higham, one way to imagine the challenges faced by such geckos in suddenly arresting their falls would be to think of a skydiver reaching terminal velocity and then grabbing a support in mid-fall and stopping without using a parachute to slow down.

Next, the researchers will travel to French Guiana in the fall to obtain video (in high speed) of the landing of geckos on leaves.

"We will combine canopy observations and field experiments with artificial landing platforms," Higham said. "Basically, we want to compare the results of our model with the actual forces of landing in nature."
The research was funded by a grant to Higham from the National Science Foundation.

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment is now nearly 23,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

University of California - Riverside

Related Biology Articles:

Experimental Biology press materials available now
Though the Experimental Biology (EB) 2020 meeting was canceled in response to the COVID-19 outbreak, EB research abstracts are being published in the April 2020 issue of The FASEB Journal.
Structural biology: Special delivery
Bulky globular proteins require specialized transport systems for insertion into membranes.
Cell biology: All in a flash!
Scientists of Ludwig-Maximilians-Universitaet (LMU) in Munich have developed a tool to eliminate essential proteins from cells with a flash of light.
A biology boost
Assistance during the first years of a biology major leads to higher retention of first-generation students.
Cell biology: Compartments and complexity
Ludwig-Maximilians-Universitaet (LMU) in Munich biologists have taken a closer look at the subcellular distribution of proteins and metabolic intermediates in a model plant.
Cell biology: The complexity of division by two
Ludwig-Maximilians-Universitaet (LMU) in Munich researchers have identified a novel protein that plays a crucial role in the formation of the mitotic spindle, which is essential for correct segregation of a full set of chromosomes to each daughter cell during cell division.
Cell biology: Dynamics of microtubules
Filamentous polymers called microtubules play vital roles in chromosome segregation and molecular transport.
The biology of color
Scientists are on a threshold of a new era of color science with regard to animals, according to a comprehensive review of the field by a multidisciplinary team of researchers led by professor Tim Caro at UC Davis.
Kinky biology
How and why proteins fold is a problem that has implications for protein design and therapeutics.
A new tool to decipher evolutionary biology
A new bioinformatics tool to compare genome data has been developed by teams from the Max F.
More Biology News and Biology Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.