posted October 25, 2013 01:42 PM            

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By Brid-Aine Parnell, 25th October 2013

Mighty Mouse GOBBLES live scorpion, LAUGHS at stings to face in video

Where IS thy sting? Oh, I've eaten it, greedy me

Top scientists have revealed that grasshopper mice feel no pain when they are stung in the face by scorpions: they simply carry on gobbling the fearsome poisonous arachnids up.

The mighty mouse, native to the southwestern US, has managed to take the toxin, which is lethal to other animals, and turn it into an analgesic that numbs pain.

Michigan State University assistant professor of neuroscience and zoology Ashlee Rowe had already figured out that the mice weren't bothered by bark scorpion toxin, but didn't know why.

“This venom kills other mammals of similar size,” she said. “The grasshopper mouse has developed the evolutionary equivalent of martial arts to use the scorpions’ greatest strength against them.”

Rowe and her team scooped up a bunch of mice and scorpions from the desert to try to figure out why. They injected both the toxin and non-toxic saline solution into the mice's paws but found that the creatures reacted much more strongly to the solution, licking their paws to try to get rid of the sting.

"This seemed completely ridiculous,” said Harold Zakon, professor of neuroscience at The University of Texas at Austin. “One would think that the venom would at least cause a little more pain than the saline solution. This would mean that perhaps the toxin plays a role as an analgesic. This seemed very far out, but we wanted to test it anyway.”

Rowe and Zakon discovered that the bark scorpion toxin binds to sodium channels in the mouse's pain neurons, which blocks them from firing off a pain signal to the brain. The neurons have two different channels, 1.7 and 1.8, and toxins traditionally stick to the former to get the channels to open and fire off the pain to the brain.

Through gene sequencing, the boffins found that the 1.8 channel in the grasshopper mice has different amino acids to the 1.8 channel of other mammals that are sensitive to the scorpion stings – which include house mice, rats and humans.

“Incredibly, there is one amino acid substitution that can totally alter the behaviour of the toxin and block the channel,” said Zakon.

However, the team still need to figure out why the grasshopper mice doesn't just die from the toxin.

“We know the region of the channel where this is taking place and the amino acids involved,” said Rowe. “But there’s something else that’s playing a role, and that’s what I’m focusing on next.”

The full study, "Voltage-Gated Sodium Channel in Grasshopper Mice Defends Against Bark Scorpion Toxin", was published in Science. ®

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posted October 27, 2013 01:46 AM            

Timon, the meerkat on The Lion King movie has immunity from Scorpion stings, too. No wonder he's singing "Hakuna Matata" (which translates to 'no worries' in Swahili).

Here are some more interesting Scorpion Fun Facts:

Scorpions have been on Earth a long time and are among the first animals to have adapted to land living—around 420 million years ago. There are fossil records from that time period of a marine scorpion that grew up to 3.3 feet (1 meter) long! Today, scorpions use book lungs to breathe, a type of breathing organ also used by some spider species and very similar to gills.

Scorpions may have as many as 45 different toxins in their venom. Some toxins are more useful on insects, some on crustaceans, and some on vertebrates. Scorpions use their venom to subdue their prey and for protection. Their predators include centipedes, shrews, owls, bats, hornbills, and coyotes. Some animals, like meerkats and mongooses, are immune or resistant to their venom.

All scorpions have venom, but of the 1,500 or so species, only about 25 are considered life threatening to humans, and only 2 of those are found in the U.S. The sting of most species is enough to kill an insect or spider but is merely painful to humans, like a bee sting. Few stings are fatal, but allergic reactions can happen. A physician should treat scorpion stings to ensure the patient recovers safely.

In Egyptian mythology, the goddess Isis was linked with scorpions, as she was a symbol of a devoted mother, and scorpion mothers protect and carry their young on their backs.

Scorpions can easily be seen at night with an ultraviolet light due to a fluorescent material found in their hard outer covering, which gives them a "glow-in-the-dark" appearance.