A terrain treadmill to study animal locomotion through large obstacles

Area of Science:

• Biomechanics
• Robotics
• Animal Behavior

Background:

• Understanding animal locomotion in complex, three-dimensional terrain with large obstacles is hindered by a lack of systematic experimental tools.
• Existing terrain arenas are limited to small spatiotemporal scales, restricting detailed observation of movement dynamics over larger scales.

Purpose of the Study:

• To develop a novel terrain treadmill capable of enabling high-resolution observation of animal locomotion.
• To facilitate systematic experiments on animal movement through large obstacles over large spatiotemporal scales.

Main Methods:

• A terrain treadmill was engineered, featuring an inner sphere with modular obstacles where an animal moves.
• A concentric, transparent outer sphere rotates via closed-loop feedback, maintaining the animal's position on top of the inner sphere.
• Locomotion was tracked using high-resolution observation during sustained movement through pillar obstacles.

Main Results:

• A discoid cockroach successfully navigated pillar obstacles for up to 25 minutes (2500 cycles) and 67 meters (1500 body lengths).
• Over approximately 1 hour of trials, the animal remained within 1 body length of the target area 90% of the time.
• The system provided high-resolution data, enabling detailed study of locomotor behaviors and animal-obstacle interactions.

Conclusions:

• The developed terrain treadmill is an effective tool for studying animal locomotion in complex 3D environments at unprecedented scales.
• This technology allows for detailed quantification of animal-obstacle interactions and diverse locomotor behaviors.
• The system opens new avenues for systematic research into the biomechanics of locomotion in challenging terrains.