The year 2025 is the Year of the Blue Snake, known as Eulsa Year (乙巳年). Snakes are animals commonly found in myths around the world. In Christianity, snakes symbolize the devil, Satan. In Greek mythology, the snake symbolizes the god of medicine, 'Asclepius,' carrying a meaning of healing. The civilization that blossomed in the desert, Egypt, suggests that the god of chaos and destruction, 'Apep (Apophis),' can transform into a snake. In South American mythology, snakes are seen as symbols of fertility and land.

Cultural perspectives on snakes vary, but in most parts of the world, snakes are commonly regarded as significant symbols. This reflects that snakes have had a considerable impact on various cultures and societies, regardless of climate and environment. In fact, snakes inhabit grasslands, jungles, deserts, and even rivers and oceans. This demonstrates that snakes have an exceptional ability to survive in diverse environments.

The research team at the Korea Institute of Robot and Convergence develops a disaster rescue snake-inspired robot. It can move freely between debris at a building collapse site, and it has a device in its head to deliver water or medications./Courtesy of Korea Institute of Robot and Convergence

◇A snake robot leading rescue efforts at disaster sites

Snakes belong to the reptile family and are close relatives of lizards, but they possess a unique appearance with both front and hind legs evolved away, leaving only a long, slender body. While it would be difficult for ordinary animals to survive in the wild without legs, snakes have established themselves as feared predators among most small animals. This is due to the snake's ability to move quickly and easily climb trees using only its body.

Scientists have taken note of the remarkable adaptability of snakes, particularly roboticists. Roboticists intend to use biomimetic technology inspired by snakes for search and rescue and military reconnaissance purposes. The unique shape of snakes allows for tasks that humanoid or quadrupedal robots cannot accomplish.

Yoon Dong-won, a professor in the robotics department at Daegu Gyeongbuk Institute of Science and Technology (DGIST), said, "Existing robots have to increase the size of their legs to enhance mobility, but by imitating snakes, movement can be achieved using only the body, allowing easy passage through narrow and deep spaces. The ability to coil and climb cylindrical structures like trees is also a strong point."

The research team at ETH Zurich develops a snake-inspired robot called RoboA. It can easily pass through narrow passages, making it useful for rescuing lives and inspecting sewers./Courtesy of ETH Zurich

Professor Yoon's research team developed a snake-inspired robot for disaster and rescue sites in 2021, in collaboration with the Korean Robotics Convergence Research Institute. In situations where buildings collapse or people are trapped due to earthquakes, the snake-inspired robot can enter debris gaps to assist in locating and rescuing missing persons. The joints are connected by motors, allowing for flexible movement even in tight spaces. The robot's head is equipped with a needle for administering fluids or medications, enabling it to provide simple assistance in emergencies.

Professor Yoon noted, "The snake-inspired robot is specialized for disaster rescue, as it can lift its head to move to higher places even when the front is blocked."

Overseas researchers are also developing robots with similar shapes to domestic robots. Researchers at the Swiss Federal Institute of Technology Zurich (ETH) unveiled a 20-meter-long snake-inspired robot called 'RoBoa' on November. The RoBoa operates using a pneumatic system that utilizes air pressure instead of motors. The ETH researchers mentioned that RoBoa can be utilized not only at disaster sites but also for inspecting urban sewer conditions.

The research team at Carnegie Mellon University develops a snake-inspired robot called Uncle Sam. It can wrap around tree trunks like a real snake to look around its surroundings./Courtesy of Carnegie Mellon University

◇Climbing trees and adhering to surfaces: snake-inspired engineering

Roboticists believe that snake-inspired robots can be utilized not only for rescue operations but also for military purposes. For instance, they can wrap around tree trunks to ascend and photograph enemy positions from a distance with cameras, or they could quietly sneak in to eavesdrop on conversations.

Professor Yoon stated, "Snakes possess the ability to move through grasslands, jungles, sandy ground, and even water, and therefore, we could develop amphibious robots that imitate snakes."

Researchers at Carnegie Mellon University in the U.S. released a video in 2010 showing a snake-inspired robot called 'Uncle Sam' climbing a tree. In the video, Uncle Sam is seen wrapping around the tree and looking around. Uncle Sam can wriggle on the ground while also being able to clasp trees or crawl inside cylindrical pipes, allowing it to ascend higher than any other robot.

The research team at the Korea Institute of Machinery and Materials creates a flexible battery modeled after snake scales. Even if the battery itself is not made of a flexible material, it can be stacked like scales, providing flexibility in multiple directions./Courtesy of Korea Institute of Machinery and Materials

The technology inspired by snakes does not stop at robotics. By mimicking the flexible body of a snake, sturdy batteries can also be integrated into wearable devices. Researchers from the Korea Institute of Machinery and Materials showcased a snake-inspired battery in August 2021. They developed a battery that resembles snake scales, allowing for a gentle curve and stretchability. This demonstrates that flexible batteries can be implemented simply by modifying the structure, even without making the battery itself flexible.

Head researcher Hyun Seung-min pointed out, "Existing batteries are prone to breaking when bent or stretched, limiting their usability in dynamic environments. By stacking batteries like the scales covering a snake's flexible body, we can design flexible and stretchable batteries that can unfold in any direction."

The research team believes that the snake scale-inspired battery can be utilized in wearable devices. For example, exoskeleton suits that assist physical abilities require a battery, but conventional batteries lack elasticity, which restricts their attachment locations and sizes. With the snake scale-inspired battery, it can be implemented even in dynamic areas like limbs, reducing the weight of wearable devices while allowing for extended usage.

Hyun, the head researcher, stated, "This battery can take on a completely transformable shape, allowing it to be used with any wearable device. Currently, we are researching technology to expand the battery itself, but the textile industry is showing great interest in snake scale-inspired battery technology."

Reference materials

IEEE Explore (2021), DOI: 10.1109/RoboSoft51838.2021.9479192

Soft Robotics (2022), DOI: https://doi.org/10.1089/soro.2020.0175

Robotics and Autonomous Systems (2012), DOI: https://doi.org/10.1016/j.robot.2011.08.010