Small as they are, grasshopper mice are surprisingly tough. Thus, it appears that these rodents can not only survive having venom from an Arizona bark scorpion injected into their bodies, but they also feel no pain when stung by one such creature.
By comparison, people who have been stung by said scorpion species say that the experience is similar to being hit hard with a blunt object.
Researcher Ashlee Rowe with the Michigan State University and colleagues say that, as surprising as this may sound, the scorpion's venom acts as a painkiller when injected into the bodies of grasshopper mice.
“The venom actually blocks the pain signal that the venom is trying to send,” Ashlee Rowe says, as cited by Live Science
“We don't want to try to sound too cute or anything, but it is sort of like an evolutionary martial art, where the grasshopper mice are turning the tables. They're using their opponents' strength against them,” the researcher further explains.
Ashlee Rowe and her colleagues hope that, in time, a more detailed analysis of how and why grasshopper mice do not feel pain when stung by an Arizona bark scorpion will lead to the development of more effective pain-blocking drugs for use in human patients.