They protect themselves from predators by camouflage when detected, many species attempt to startle the predator with a brilliantly-coloured wing-flash while jumping and (if adult) launching themselves into the air, usually flying for only a short distance. Grasshoppers are plant-eaters, with a few species at times becoming serious pests of cereals, vegetables and pasture, especially when they swarm in their millions as locusts and destroy crops over wide areas. Under these circumstances, they are known as locusts. At high population densities and under certain environmental conditions, some grasshopper species can change color and behavior and form swarms. As hemimetabolous insects, they do not undergo complete metamorphosis they hatch from an egg into a nymph or 'hopper' which undergoes five moults, becoming more similar to the adult insect at each developmental stage.

Grasshoppers are typically ground-dwelling insects with powerful hind legs which allow them to escape from threats by leaping vigorously. They are among what is probably the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshoppers are a group of insects belonging to the suborder Caelifera. American grasshopper ( Schistocerca americana)