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Cats are creatures of mystery.
Why do they always orient themselves to you backside-first?
Why do they scream for food they’re not going to eat?
And what’s with catnip?
Well, a team of Japanese researchers have done what might be
the most fun study in the history of ever —
and they may finally have an answer for that last one.
Many cats, though not all, exhibit a behavior similar to intoxication
when they encounter catnip, as well as another plant called silver vine.
They rub their faces in it, roll around in it, and generally do hilarious things.
Catnip and silver vine don’t cause any physical or neurological damage,
the way intoxicating substances can in humans.
And it’s funny, so we humans will happily fill cat toys with the stuff so we can
elbow each other and make fun of Fluffy for being in a state we technically caused.
We’ve known for a while that the feline love of catnip and silver vine is inborn.
In fact, the catnip response is at least partly genetic.
For most people, catnip is just a fun way to play with our pets.
But the Japanese team wanted to know more about the how and why.
So in a paper published in Science Advances in 2021, they soaked filter paper
in nepetalactol, a chemical isolated from silver vine that gives it that zing.
When they exposed cats to the paper, the cats responded
in pretty much the same way that they do to catnip and silver vine plants.
That is, adorably.
The researchers were able to show that this compound
directly activated a reward system in the feline brain.
Which is a start — it tells us what’s going on in their little heads.
But the researchers wanted to know why such a response
would evolve in the first place.
It’s super cute, but cuteness is probably not the evolutionary fuel
that powered this particular adaptation.
For example, you might guess that humans
had selectively bred it into our pets because we think it’s funny.
But it’s not just domestic cats who like catnip.
Other felines like catnip too — even big cats like lions are known to indulge.
It’s much more likely that these plants provide some other advantage.
As a starting point for a hypothesis, the researchers observed that humans
sometimes use silver vine as a mosquito repellent.
And since cats do like to roll in catnip and silver vine,
the team suspected they might be transferring nepetalactol onto their fur.
Which means that for cats, the stuff may serve as both a ticket to La-La Land
and a way to ward off blood-sucking pests.
So a win-win.
First, the researchers confirmed that mosquitoes
avoided both silver vine and purified nepetalactol.
They once again tempted cats with nepetalactol-laced paper,
and confirmed that the cats transferred some of the compound to their fur
when they rubbed their faces on the paper.
Then, they exposed the kitties to a bunch of mosquitoes —
definitely the least fun part of the study.
But they did confirm that mosquitoes landed less often
on cats with nepetalactol in their fur.
This gave them pretty clear evidence that there’s a mosquito-repelling benefit
to playing in catnip and silver vine.
More research needs to be done, however.
Just showing there’s a benefit doesn’t prove that the catnip response
evolved for that reason.
So the next step is to do genetic studies to learn more about the genes involved,
and how and when they came online.
So I guess those poor researchers will just have to do
more super fun studies with cats and silver vine until they finally learn the truth!
It’s rough being a scientist, you know?
You know what’s awesome, though?
Making videos with the help of awesome people.
Especially this month’s President of Space, Matthew Brant.
We are so lucky to have you — and each and every one of our patrons, too.
If you’d like to support SciShow, you can go to patreon.com/scishow to learn more.
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