91av

Species:

Habitat: isolated patches of desert from , though there might actually be

Does anything eat wasps, a 91av reader once wondered, and the answer turned out to be . In a way that’s not surprising, as wasp stings are painful but rarely fatal. Perhaps a better question would be, does anything eat scorpions?

Humans do. Scorpions may be or – but we don’t usually let them sting us in the face first. The desert long-eared bat – surely the toughest bat in the canopy – does.

On the prowl

of Ben-Gurion University of the Negev in Midreshet Ben-Gurion, Israel and colleagues knew that the bats ate scorpions, because , along with those of other arachnids and various insects. Sometimes over 70 per cent of the remains came from scorpions. But they didn’t know how the bats coped with such a challenging meal.

Korine’s team first went to a park where the bats , and fixed eight live to the ground with string. They found that the bats foraged in pairs or larger groups, flying just over 2 metres above the ground. Every so often one would suddenly drop to the ground, landing on a scorpion.

The team then captured eight bats and watched them hunt scorpions in a room at their lab. The bats completely ignored freshly dead scorpions, and only attacked live ones that moved.

The bats showed an interest in boxes with live scorpions inside them, suggesting they were homing in on sound. To check that that was possible, Korine measured the sound of the scorpions walking on soil. He found that at the bats’ flight altitude they would hear it as a 30-decibel rustling, which would be easily detectable. The bats also emit , but Korine says the masking effects of vegetation would probably confuse any signals bouncing off scorpions.

Do your worst

When a bat landed on a scorpion, it immediately tried to bite the scorpion’s head. The scorpion fought back by stinging the bat in the face, and on one occasion under the eyelid. The bat didn’t try to avoid it, or to break the stinger, and showed no ill effects whatsoever.

Once the scorpion was dead, the bat carried it back to a and ate it head-first. In most cases it ate the whole thing, including the stinger and poison gland.

The bats’ devil-may-care approach to hunting doesn’t stop there. They attacked different scorpion species equally, regardless of how venomous they were: they were just as happy with relatively harmless as with moderately toxic common yellow scorpions. Both pale in comparison with the 10-centimetre , which is popularly known as the death stalker because of its . The bats ate those just as willingly, stings or no.

It’s possible that in some cases the stingers weren’t able to break the bats’ skin, but the bats often went ahead and ate the entire poison gland anyway.

Korine thinks that they must have evolved resistance to the scorpions’ venom – though they don’t seem to have figured out the endive recipe just yet.

Journal reference:

Read previous Zoologger columns: Houdini fly inflates head to break walls, A primate with eyes bigger than its brains, The solar-powered electric hornet, The miniature cuckold fish, Lemmings swap suicide for infanticide, The slow-moving mystery of the sloth’s neck, How weakness makes the crayfish stronger , The heaviest animal in the air, Ancient air-breathing, triple-jawed fish, Horror fly returns from the dead, Even parasitic worms have a divided society