Grasshopper Mice Numb to the Pain of the Bark Scorpion Sting

Posted on October 25, 2013

Grasshopper mice are numb to the pain of the pain of the bark scorpion sting. The venom from the scorpion can kill other mammals of a similar size. Scientists have discovered that to the grasshopper mouse the scorpion toxin acts more like an analgesic than a pain stimulant.

To test whether the grasshopper mice felt pain from the toxin, the scientists injected small amounts of scorpion venom or nontoxic saline solution in the mice's paws. The mice licked their paws (a typical toxin response) much less when injected with the scorpion toxin than when injected with a nontoxic saline solution.

Ashlee Rowe, Michigan State University assistant professor of neuroscience and zoology and lead author of the paper, says in a statement, "This venom kills other mammals of similar size. The grasshopper mouse has developed the evolutionary equivalent of martial arts to use the scorpions' greatest strength against them."

Rowe and Harold Zakon, professor of neuroscience at The University of Texas at Austin, discovered that the bark scorpion toxin acts as an analgesic by binding to sodium channels in the mouse pain neurons. This blocks the neuron from firing a pain signal to the brain.

Here is a grasshopper mouse attacking a bark scorpion and getting repeatedly stung in the face. Take a look:

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