Watching squirrels is almost as exciting as watching a trapeze act in a circus. The goblin-like animals jump from tree to tree at a dizzying height, overcome distances of several meters and land safely on swaying branches. Everything happens at breakneck speed, but it almost never happens that one of the animals crashes. How do the rodents, which are around 8 inches tall, do it?
A team led by biologist Nathaniel Hunt from the University of California at Berkeley has now found that squirrels check the stability of their starting branch and the distance to the target before each jump in order to find the optimal jump position. For their study, which is currently in the science journal Science has appeared, the team of biologists, biomechanics and psychologists set up a kind of outdoor parkour on the university campus. Then the researchers used peanuts to train wild squirrels that live nearby to perform acrobatics. Everything was recorded with high-speed video cameras.
In one of their experiments, the scientists varied the flexibility of the jump poles by using different materials: birch wood, plastic and a plastic tube reinforced with copper. They also changed the distances between the end of the pole and the target location.
Although all the poles were the same length, the animals jumped off in different places. “When deciding where to jump, the squirrels take into account the stability of the launch and the distance to the target,” the study authors write. In other words, the animals know that although the distance to the target is reduced when they run to the very end of the pole, this also makes their point of departure less safe.
The animals can correct mistakes in flight
Further experiments showed that the animals were able to correct misjudgments even in flight. Plus, after familiarizing themselves with parkour, they got creative and invented new ways to achieve their goal.
All of these skills prevent squirrels from falling during their maneuvers. Because conditions are also constantly changing in nature: trees grow or become rotten, and the conditions in winter are very different from those in summer. The animals themselves are also changing, becoming bigger and heavier on the one hand and getting more and more experience on the other.
Squirrels aren’t the only animals that have to adapt their movements to the conditions in their environment. This necessity is not always as obvious as it is with the little rodents, who otherwise would keep falling and breaking all bones. But in principle hardly any living being can afford to move rigidly and inflexibly through the world. For example, bats and green iguanas take into account that they are heavier if they have just eaten their fill.
Also, human children “move to learn while learning to move.”“write Karen Adolph of New York University and Jesse Young of Northeast Ohio Medical University in Science. Some grow up to two centimeters in a single day and their locomotion skills change within a very short time. “One week they crawl, the next they can walk,” write Adolph and Young. In order to cope with such changes, it takes adaptability and creativity, similar to the squirrels.