Why Do Jumping Beans Jump?
A jumping bean’s movement is caused by a tiny insect that lives inside the bean. A jumping bean is the seed of a shrub that grows in Mexico.
When the shrub blooms, certain moths lay eggs in the blossoms. As the bean forms, the egg inside, hatches into a tiny caterpillar. As it grows, the caterpillar eats the inside of the bean.
When the sun warms the bean, the caterpillar gets hot, and vigorously jerks its body. Jumping beans jump as a way of surviving.
This enables them to bounce to a cooler place to avoid the heat and the sun. Each time it moves, the bean jumps and rolls.
After several months, a hole appears in the bean and a little gray moth comes out and flies away.