Crawling

Crawling is a form of animal locomotion generally involving slow movement along the ground, such as that seen in snakes, snails and earthworms. Various mechanisms are involved, for example earthworms move by peristalsis, while snakes undulate their body from side to side. This form of terrestrial locomotion involves much higher levels of friction than running, hopping etc.

Human crawling
For humans it usually means moving on knees and hands, with support from the toes. Except for using a vehicle or being carried by an animal, it is the main alternative to walking and running. Crawling is used mainly:
 * When he/she cannot walk because of being an infant or due to disability or being wounded or sick.
 * In very low places (caves, under a table, in a mine, etc.). Sometimes underground miners need to crawl long distances during their work.
 * When searching for something on the ground.
 * To get down to the ground in gardening
 * For stealth (camouflage and quietness)
 * To lower the field of vision
 * For fun or comical purposes.
 * When gun fire or other projectiles are flying over, crawling reduces the risk of being hit.

Crawling sensation
Crawling, in terms of pain sensations, refers to feeling as if covered with crawling things (i.e., ants).