Baby Mice Exposed to Cat Urine are Less Afraid of Cats

Cats are scaring away mice without having to even raise a paw. But there is one way to prevent the little critters from backing down in the face of danger. According to new research presented at this year’s Society for Experimental Biology meeting in Prague, if a baby mouse is exposed to the L-Felinine compound found in cat urine, they are less likely to run from cats when they’re older.

Dr. Vera Voznessenskaya of the A.N. Severtsov Institute of Ecology and Evolution in Moscow discovered that the same chemical that triggers an increase in stress hormones, and can cause pregnant mice to abort, is responsible for this odd mouse behavior.

During their study, the team exposed mice to L-Felinine when they were babies, and then again when they were adults. Because the baby mice were being fed milk in the initial stage, “they experience positive reinforcement,” when they smell the scent again, Dr. Voznessenskaya stated in the press release.

While they don’t run from the scent, the mice's brains did produce the same stress hormones in response to the odor as the control group—they just didn't act on it.

Dr. Voznessenskaya thinks that the rodents’ ability to function around cats—in this case, house cats—ensures that they have easier access to food, as both animals rely on humans for nutrition. A mouse that can’t occupy the same space as a cat is left to its own devices to find sustenance, and may be less successful.

But just because the mouse has adapted doesn’t mean the cat has too. As fancy as today's gourmet cat foods are, few cats can pass up a good mouse for dinner.