Cats and fish: a tale as old as time

Put a fish anywhere near a cat and something ancient seems to awaken. Eyes widen. Nose activates. Whiskers twitch.

It’s such a familiar pairing we barely question it. Cats eat fish. Obviously. Cartoon cats steal fish from market stalls. Storybook cats dream about sardines. Real cats can apparently hear a pouch of Splash being opened from three postcodes away.

But here’s the slightly weird bit: the domestic cat’s ancestors weren’t exactly spending their evenings hauling salmon out of rivers. Cats are land-dwelling hunters and most aren’t famously enthusiastic swimmers. So how did fish become such a huge part of feline food culture?

Turns out, humans may have had quite a lot to do with it.

Go back thousands of years and the human-cat relationship was already based on an extremely sensible bit of mutual exploitation.

We stored food. Rodents turned up to eat it. Cats turned up to eat the rodents. Humans looked at the cats and thought: excellent employee, no salary required.

As cats moved closer to human settlements, they gained access to foods they wouldn’t necessarily have hunted for themselves – including fish.

There’s evidence of the connection surprisingly far back. In Ancient Egypt, fish from the Nile were an important part of the human diet and cats would have had plenty of opportunities to scavenge scraps. One Egyptian tomb painting from around 1470 BC even depicts a cat eating a fish. So the whole ‘cat loses mind over fish’ thing is, technically speaking, vintage.

And the archaeological evidence suggests this wasn’t just artistic licence. Research on cats from medieval harbour settlements in Oman and Iran found that some were eating diets rich in marine protein, probably thanks to fishing waste and food scraps supplied – deliberately or otherwise – by humans.

In other words: fishing communities had fish. Cats lived around fishing communities. Fish bits fell on the floor.

Cats are nothing if not opportunists.

Eventually, cats didn’t just hang around the harbour, they joined the crew.

Ships carrying grain, food and other supplies had a fairly predictable problem: rats and mice. Aside from eating provisions, rodents could damage equipment and generally make themselves profoundly unpopular.

Enter: Cats.

Cats became useful companions aboard vessels because they could help keep rodent populations under control. They were also kept as pets and mascots: Royal Museums Greenwich notes the long history of cats travelling with sailors and records, among others, Trim, the cat who accompanied explorer Matthew Flinders on his circumnavigation of Australia in the early 1800s.

Imagine the arrangement from the cat’s perspective.

Job description:

• Chase mice occasionally.

• Receive affection from lonely sailors.

• Live inside enormous floating cupboard full of fish.

Frankly, excellent career progression.

Fishing vessels in particular would have provided cats with ready access to offcuts, guts, small fish and other bits humans didn’t want. Traditional European fisheries are known to have used lower-value fish as animal feed, including for cats.

Over generations, fish therefore became something many domestic cats encountered regularly because humans made it regularly available.

Not quite an ancestral feline fishing expedition, then. More an extremely long-running catering arrangement.

Naturally, artists got involved.

Because if you put a cat and an unattended fish in the same room, you’ve already got narrative tension.

One particularly glorious example is Giuseppe Recco’s 17th-century painting A Cat Stealing Fish. It shows a cat enthusiastically helping itself to seafood – specifically an octopus – among an elaborate still life of marine delicacies.

The association crops up again and again in visual culture: fishmongers’ stalls, harbour scenes, kitchen paintings and cartoons. Fish became almost a piece of artistic shorthand for feline temptation.

Show a cat.

Show a fish.

Audience immediately understands what happens next.

Chekhov had his gun. Cats have unattended mackerel.

By the time popular culture really got hold of the relationship, cats and fish were practically inseparable.

Children’s books, comics, animated films and television repeatedly present fish as the ultimate feline prize: the dangling fish skeleton, the goldfish bowl receiving an ominous stare, the cat creeping away from the kitchen carrying something suspiciously tail-shaped.

Think of the basic cartoon logic.

Dog: bone.

Mouse: cheese.

Cat: fish.

Biological accuracy has left the chat.

That cultural association became self-reinforcing. People expected cats to like fish, so fish increasingly appeared in commercially prepared cat foods. Cats ate those foods. Advertising showed cats loving fish. Humans became even more convinced that the natural state of the domestic cat was sitting beside a lighthouse demanding cod.

And yet there is some proper biology behind the obsession.

One word: Umami.

Which is Japanese for ‘pleasant savoury taste’ and human for ‘why have I just eaten half a block of Parmesan standing over the sink?’

Cats are obligate carnivores. Their bodies are built around eating animal tissue and their taste system reflects that.

They possess receptors capable of detecting amino acids associated with savoury, protein-rich foods. Research into feline taste receptors has shown that cats are particularly responsive to compounds involved in umami perception.

And some fish are basically umami fireworks.

Tuna is a particularly interesting example. Research has found that cats’ umami receptors respond strongly to the combination of histidine, an amino acid, and inosine monophosphate (IMP), a nucleotide – both of which are abundant in tuna. When researchers offered cats different flavoured liquids, that combination was especially popular.

Wildcats probably didn’t evolve eating huge amounts of fish.

The African/Near Eastern wildcat ancestors of domestic cats mainly hunted small terrestrial prey: rodents, birds and other creatures they could catch on land.

Meaning the famous cat-fish romance probably isn’t simply some prehistoric biological destiny.

It looks more like a combination of carnivore taste biology + opportunity + thousands of years hanging around humans who kept dropping fish everywhere.

Which, really, is quite cat.

They didn’t invent fishing.

They simply found a species willing to do it for them.

Once upon a time, a cat may have waited beside a Nile fisherman for a scrap.

Later, another prowled the deck of a ship while sailors hauled in their catch.

Another appeared in a Renaissance painting with its face buried somewhere it absolutely should not have been.

Today, one hears a pouch opening from the kitchen and materialises beside you before you’ve even finished tearing it.

Different century. Same cat.

Our relationship with cats has changed enormously: from pest controllers to shipmates to pets who occupy 78% of the bed despite weighing four kilos.

But food has always been part of the deal. Humans provided opportunity > cats developed preferences > culture turned those preferences into stories, paintings, cartoons and clichés.

And beneath all of that history sits a very simple biological truth.

Cats are carnivores.

Fish is rich in the savoury flavours their senses are brilliantly tuned to detect.

So perhaps cats and fish really are a tale as old as time.

Or at least a tale as old as one species learning to catch fish…

…and another deciding it would rather wait by the bucket.