

Two small but fierce animals live in the Sonoran Desert of the southwestern United States and northern Mexico. One is the Arizona bark scorpion (Centruroides sculpturatus), and the other is the southern grasshopper mouse (Onychomys torridus). The scorpion and the mouse give medical science an insight into pain relief.
Arizona bark scorpions grow to barely more than three inches (8 cm) long, but their stingers pack a wallop. They are nocturnal foragers, feeding on insects, including beetles and roaches. They can live up to six years and sometimes congregate in packs. Many of them survived intact close to ground zero when the United States conducted atomic blast tests in the desert. Their venom is the most potent of any scorpion in North America, and it can be fatal to small animals, children, the elderly, or the sick.
However, Arizona bark scorpions are up against a small predator with a strong defense. The southern grasshopper mouse eats grasshoppers, centipedes, snakes, and scorpions. These mice are immune to the venom of snakes and scorpions. They also eat highly venomous centipedes, which could kill the mouse. However, this courageous mouse sneaks up and pounces on its prey like a cat.
The southern grasshopper mouse has an excellent defense against the terrible pain from the Arizona bark scorpion’s sting. If the scorpion stings humans or ordinary mice, sodium channel proteins in the skin send a painful message to the brain. However, when the southern grasshopper mouse is stung, channels block the flow of sodium, and the pain is quickly gone. More than that, researchers found that the venom injection also blocked other pain sensations for the mouse.
The scorpion and the mouse can teach a lesson to medical scientists working on pain-relieving drugs. Doctors have been trying to find ways to block human pain channels for years. The southern grasshopper mouse may have the solution if we can learn how the system works and how we can duplicate it. Science has made many medical discoveries by studying God’s design in the natural world.
— Roland Earnst © 2025