How squirrel became a "parkour master"

How squirrel became a "parkour master"

How squirrel became a "parkour master" How squirrel became a "parkour master"

Squirrel "Parkour" appeared on the cover of the latest issue of "Science"
.

Image source: Research Group/Science

Squirrel "Parkour" appeared on the cover of the latest issue of "Science"

As a natural "parkour master", how does a squirrel judge how far he can jump? Can people learn their flexible posture to ensure more effective exercise? Can robots "learn" their ability to evaluate themselves?

Recently, a study published in "Science" tried to find the answers to these questions
.

Researchers analyze the instantaneous decisions made by squirrels when they cross the tree canopy and jump high to understand how they recognize the limits of their agility, thereby helping to develop robots that move flexibly in different environments, such as search and rescue robots

To jump or not to jump?

To jump or not to jump?

"China Science News" learned from the University of California, Berkeley, that the biologist Robert Full of the school has devoted himself to studying how animals such as geckos, cockroaches and squirrels move in the past few decades, and how their bodies and limbs help them make breakthroughs.
Dilemma
.

But how do these animals decide whether to jump? Obviously, luck cannot make every seemingly extreme jump succeed
.

"Animals must match behaviors to local conditions, generate perceptual information about which actions are feasible, and then select appropriate ones from the possible options

To find out, Full and Nathaniel Hunt, assistant professor of biomechanics at the University of Nebraska, and others observed free-range squirrels
.

In the eucalyptus forest at the University of California, Berkeley, they used food to lure squirrels into an environment suitable for observation

"The tree canopy is an ideal natural laboratory
for studying perception-behavior coupling .

For arboreal animals, mistakes can have serious consequences.

Full found that when squirrels want to jump from a branch, the weaker or smoother the branch, the more cautious they are
.

Moreover, squirrels have adapted to different environments after only a few attempts

"When crossing a gap, they will measure the elasticity of the branches and the size of the gap that must be crossed to determine where to start
.

" Hunt told the China Science News, "When they encounter branches with new mechanical properties, they will Adjust the jump action in several jumps

When a squirrel makes a decision, the flexibility of the jumping tree and the jumping distance are not as important
.

In fact, tree elasticity is 6 times more important than spacing

"Their paws are almost foolproof, so that squirrels never fall, even though they sometimes jump too high or too low
.
" Hunt said, "They don't always achieve the best'scores', but as long as they are good enough That's it
.
Even if they miss the jump, they can still grab the branches
.
"

This is where innovation comes into play when squirrels find the best jumping strategy
.

Learn from trial and innovate while learning

Learn from trial and innovate while learning

In addition to how squirrels judge the take-off action, the researchers also quantified how they change the landing action and their attitude in the air in real time based on the stability of the landing site
.
It turns out that if the squirrels are too fast or too low when they fly into the air, they can use a variety of flexible landing methods for maneuver compensation
.

If they jump too far, they will roll forward around the branches; if they jump too close, they will land on their front legs, then sway under the branches, and use their claws to pull themselves onto the branches
.
"This combination of adaptive planning behavior, learning control and response stability operation helps them move quickly between branches without falling
.
" Hunt said
.

After flying into the sky, Squirrel also has unexpected innovations
.
In the process of complex jumping, they usually adjust their body direction and push down from a vertical surface, just like human "parkour", adjusting to a suitable speed to ensure a better landing
.

One of the key factors that support the squirrel to complete this series of decision-making processes and actions is the brain
.
Squirrels and other rodents that live in trees have evolved larger brains than burrowing animals
.
This stronger brain power gives them the key abilities needed to thrive in woodland, including better vision and motor skills
.

Researchers from the University of Edinburgh in the United Kingdom performed CT scans on the skulls of 38 existing and extinct rodents to study how the animal’s brain changes over time
.
A paper published in "Communications Biology" shows that the relative size of the squirrel brains has increased over time, mainly due to their sharp decline in weight
.
Moreover, the neocortex in the two key areas of the brain related to vision and motor skills has become larger, and the petrous lobules that help stabilize eye movements have also grown
.
The researchers said that the expansion of these areas helps rodents living on trees adapt to life in a complex environment
.

In addition, Hunt et al.
believe that trial-and-error learning controls usability perception during a single jump
.
Adult squirrels have been learning all their lives, accumulating experience of the relationship between the environment and their movements, so the developmental process is also a key link for animals to learn to measure and adjust their movements
.

Effective movement lies in matching the environment

Effective movement lies in matching the environment

In nature, animals always have extraordinary athletic abilities: mites can lift 1,000 times their body weight, mantis shrimp attack their prey with bullet-like power, and peregrine falcons dive toward the prey at a speed of 539.
13 km/h
.
Even human babies can move a distance equivalent to 8 football fields per hour when they are playing freely
.
However, in the real world, animal movements are not always in the strongest, fastest or most active state
.

"To be precise, effective action is a process of matching the physical state with the environmental characteristics at all times
.
That is, the movement must be adapted to local conditions
.
" Adolph said, "The human perception of movement is also an iterative process.
In this process , The experience of moving in a variable environment produces new revelations, which in turn promotes new experiences
.
Squirrels and other arboreal animals are likely to show similar calibration abilities and creativity when learning how to jump on the canopy
.
"

Sports in the real world require flexibility and creativity
.
"I think squirrels are the best model creatures for understanding the biological limits of balance and agility
.
" Hunt said, "If we can understand how squirrels do this, we will find that it is suitable for other creatures under tree canopies and other complex terrain.
General principles of high-performance movement of animals and robots
.
"

"I think this is the next frontier, that is, how the body determines movement
.
This is an important basic biological problem
.
" Full said that they will continue to explore the interaction between animal biomechanics and cognitive abilities
.

Obviously, this experiment proved what everyone knows: in the complex woods, squirrels are clever acrobats
.
(Source: Tang Feng, China Science News)

Related paper information: https://doi.
org/10.
1126/science.
abe5753

https://doi.
org/10.
1126/science.
abe5753 https://doi.
org/10.
1126/science.
abe5753