There exists around seventy scorpion species that dwell in the United States. These arachnids are widespread in the desert regions of the southwest US, but many relatively harmless scorpion species can also be found in states along the southeast and even into the mid-east US. Of all the scorpion species that exist in the US, the most venomous is undoubtedly the Arizona bark scorpion. This species, which is often referred to as simply “bark scorpion,” is the only species in the US that is truly considered to be potentially deadly to humans. In fact, the bark scorpion is one of the most venomous scorpion species in the entire world. This scorpion species is most abundant in the state of Arizona, but these scorpions are widespread in the region ranging from southern California to western New Mexico and down into Mexico. What is perhaps more amazing than this scorpion’s venomous sting is the mouse species that willingly allows itself to sustain repeated stings from this scorpion. This mouse species is not only unharmed by repeated bark scorpion stings, but it also proceeds to feed on these scorpions by first consuming the stinger before moving on to the bulb containing the typically deadly venom. So why and how does this mouse species tolerate these stings?
The particular mouse species being discussed is commonly known as the grasshopper mouse, and strangely enough, bark scorpion venom allows this mouse to avoid pain rather than experience pain. Amazingly, the brain of a grasshopper mouse has evolved to make use of bark scorpion venom as a painkiller. After happily sustaining several stings, a grasshopper mouse proceeds to eat the entire scorpion before consuming its venom bulb in an effort to make the most of the arachnid’s valuable venom. Obviously, grasshopper mice dwell within the same desert region where its prey, bark scorpions, also dwell. The grasshopper mouse likely evolved this neurochemical trick in order to survive in a habitat where scorpions had been a constant threat. Ironically, a few genetic mutations converted this mouse species from a scorpion prey animal to a scorpion predator, and the worst kind of predator, as bark scorpions are defenseless against their attacks.
Have you ever heard of any other animal that is curiously unaffected by otherwise harmful insect or arachnid venoms?