Grades K–2 · Organisms
How can a caterpillar hold onto a twig?
A caterpillar has jointed legs near its head, but many also have soft, short supports farther along the body. These are called prolegs. They help hold the animal on a twig.
In the diagramSmall hooked supports grip a twigenlarged hooks
At the ends of the prolegs are tiny hooks. The hooks can catch against uneven parts of a surface. Several grips can support the soft body while another part moves forward.
Muscles let the caterpillar lift and release a grip, then place it farther along. The hooks are not little wheels or sticky glue. Gripping, releasing and moving different body parts work together as the caterpillar crawls.
About this explanation
Starting knowledge: Recognize a caterpillar and understand that a small hook can catch around an uneven surface.
Sources
- Huai-Ti Lin and Barry Trimmer, Frontiers in Robotics and AI — Caterpillar Climbing: Robust, Tension-Based Omni-Directional Locomotion