Male Mice are Scared of Bananas

Remember when we discovered that cats are frightened by cucumbers? We still don't know why, but it's probably just the appearance of a novel item they aren't familiar with. That meme went viral, so everyone had to try it. But this one is real- male mice go into high stress in the presence of bananas. I guess that's good for banana trees, but this particular fear developed for a different reason.

Mice from different experiments happened to be in the same lab at McGill University, and researchers noticed a stress response in male mice when they were in the presence of pregnant or lactating females. Wanting to find out why, they designed other experiments to see what chemical may have caused it. They narrowed it down to a compound called n-pentyl acetate in the pregnant/lactating mice's urine, which induces a stress response in male mice, particularly virgin male mice. That's an adaptive strategy, as male mice tend to kill baby mice.

But wait a minute. It turns out that n-pentyl acetate is the chemical that makes a banana smell the way it does! So of course the researchers went to a supermarket and bought some banana oil to check their work. Sure enough, the male mice were terrified when they were exposed to banana oil in the room. It you don't have a cat, you might be able to deter at least some mice by sticking cotton balls soaked in banana oil around the house. Maybe. The chemical also induced an analgesic effect in the mice. You can read more about these experiments at LiveScience. -via Damn Interesting