– English Lyrics

Lyrics & Translation

[English]

[ ♪ INTRO ♪]

Picture this:

Your favorite feline

splashing around in the ocean,

diving under the waves,

taking down a southern bluefin tuna the size of a bear…

But Wait, no!

That’s all wrong.

Mr. Whiskers fits neatly into a handbag

and prefers sunbeams over surf.

There is exactly no chance he’s taking on a tuna.

So why does he lose his mind

when you pop open a can of Starkist?

It doesn’t make a whole lot of sense,

because cats evolved in the desert,

where there is literally no tuna.

Or any other kind of fish.

Their ancestors

were wild cats

native to north Africa and southwest Asia,

and they've likely been living alongside us

since the early Neolithic period.

Fast forward a few thousand years

to the invention of Fancy Feast,

and the arrangement

is working out pretty well.

But there’s no denying

that most cats

would choose a stinky can of tuna

over the dozens of available

Fancy Feast flavors.

Cats –

and humans, too –

enjoy certain foods because of the umami.

Umami is the word

that describes savory, meaty flavors.

In both cats and humans,

the ability to taste umami

has to do with two proteins

called Tas1r1 and Tas1r3.

In humans,

these two molecules form a receptor

that detects the amino acids

glutamic acid and aspartic acid,

which make your brain say “umami.”

Amino acids are the components

that make up protein,

so it makes sense for them

to taste good.

That’s valuable energy right there!

In fact, glutamic acid

is the stuff in food additive MSG –

it’s basically pure umami flavor.

Nucleic acids also play a role,

acting as flavor enhancers.

When you hear the term “nucleic acid,”

you might think of DNA and RNA.

Those are the most familiar types

of nucleic acids,

but there are also a variety of nucleic acids

present in all kinds of biological tissue

– including food.

These compounds help

give food its flavor.

But in cats,

the ability to taste umami

works sort of opposite

to the way it works in humans.

They’re tasting an almost

totally different umami

to what we taste.

In a 2023 study, researchers

used computer modeling of protein structure

as well as cell line studies of cat taste receptors

to help suss this out.

And before you accuse them of taking

their research too seriously,

they also did cat taste tests.

This helped them figure out what molecules in food

were the primary drivers of whether a cat thinks something tastes good.

In cats, the Tas1 receptor pair

is not activated by just amino acids.

Instead,

it’s activated by certain nucleic acids

and enhanced by amino acids.

A nucleic acid

called inosine monophosphate,

or IMP, is

enhanced by a number

of different amino acids,

including one called histidine.

And for cats, the IMP

and histidine combo

is a powerful flavor combination.

really takes them to flavor town.

Tuna just happens to contain a lot of IMP

and a lot of histidine.

In fact, it has more IMP

than any other nucleotide,

and more histidine

than any other free amino acid.

So, that does explain

why Mr. Whiskers begs for

your tuna salad sandwich

even though he’s not ever going to

singlehandedly land a bluefin.

Other types of fish also

contain these components,

but not as much of them.

Even rat meat,

a more likely prey item for cats,

is pretty low in histidine.

And meats like

chicken, beef, and pork

don’t seem to have any free histidine at all.

The good news is,

cats also like other combinations

of amino acids and nucleic acids.

So they’re not going

to come for you in your sleep

if you put something else in their bowl.

I mean, Probably.

So why would cats evolve

to prefer something that lives

thousands of miles from their homeland

in an environment

they could never physically enter?

Well that’s…

not super clear.

A researcher who was not involved

with the study speculated

that cats who hung around

fishing ports eating scraps long, long ago

might have had an advantage

over the ones who still had

to catch mice like a bunch of suckers.

And there’s evidence that domesticated cats

were eating fish thousands of years ago,

so it’s not like this

is a super recent development.

So your kitty’s food preferences

basically have more

to do with the interactions

between amino acids and nucleic acids

than with what their wild ancestors ate,

or even what’s good for them.

Which is why we should note

that not only is tuna

not natural prey for cats,

it’s also not especially healthy.

Neither raw nor canned tuna

are nutritionally complete,

so tuna should be a treat,

not a main meal.

And even though you might never get

to see Mr. Whiskers

pull humongous fish out of the ocean,

maybe it’s enough

to know that he totally wants to.

And it won’t hurt

to give him a spoonful of the stuff

every now and then.

That way you can both pretend.

Now If you enjoyed this fun,

lively story

about the science of cats and thought

“Man, my kids slash students

slash nieces and nephews

would love this if it was just written

on a second grade level

with some educational standards

thrown in,”

ok, And you might say

“Stefan, that’s very specific”

but also I have good news for you.

Because we have a whole channel

just for kids,

and we have an episode

where Squeaks the robot rat

learns about why cats have whiskers,

Which you can find a link to

in the description.

SciShow Kids

is written with

early-grade Next Generation Science Standards

in mind to help kids grasp

age-appropriate ideas.

And it’s also just a ton of fun.

So send the young curious mind

in your life

to youtube.com/scishowkids,

and thanks for joining us today.

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