Grasshoppers breathe through 10 pairs of tiny holes called spiracles, which are located in the thorax and abdomen. Air enters the grasshopper's body through the front spiracles and exits through the rear.
Grasshoppers have clear blood and a tube-like heart. Long-horned grasshoppers have hearing organs located on their front legs, and short-horned grasshoppers hear through openings on the abdomen under the wings. Grasshoppers appear to have only two large, compound eyes; however, they actually have five. The component lenses of the two large eyes move independently but form a complete picture. There are three small eyes on the top of the head that only see in black and white. Grasshoppers use antennae to feel their way around the environment, and they also smell with them.