One day, John and Sue were out hiking. They saw a few tarantulas on the way. This gave John an idea to win some money. “Sue,” he said, “I’ll bet you five dollars that the tarantula over there can crawl without using its own leg muscles.” Sue thought that she would win, but she didn’t.
How can this be?
Answer
Tarantulas do not use muscles to move their legs. They control the amount of blood pumped into them to extend and retract their legs.