A horse in Berlin could do arithmetic. Ask him seven plus five and he tapped a hoof twelve times, then stopped. Crowds came. Newspapers came. Eventually scientists came.
His name was Clever Hans, and his owner, Wilhelm von Osten, genuinely believed he had taught a horse to count…
In 1971, a physics laboratory in Illinois hired a ferret.
Fermilab had a problem. Their beamline pipes were long, narrow and spotless-critical — a smear of grease or a stray metal filing inside could ruin an experiment. No human arm reaches that far, and the robotics of the day…
Before filters, before air pumps, there was a woman in London pouring water between two jars while her maid took the next shift.
In the 1840s, Anna Thynne kept stony corals and seaweed alive in glass containers in a London house, far from the sea. She had no way to oxygenate the…
Look closely at the Last Supper painted in Cusco Cathedral, and the dish in the middle of the table isn't lamb. It's a guinea pig, served flat with its little feet in the air.
The painting comes from the colonial Cusco school, where Andean artists worked in a European style and…
The dog has been with us for tens of thousands of years. The cat for thousands. Your rabbit? A relative newcomer.
Wild European rabbits come from Iberia and southern France. The Romans kept them in walled enclosures called leporaria — not as pets, but as a larder that fed itself…
The fish gliding under the lilies started out as a winter food store.
In the snow country of Niigata, in the mountains of northern Japan, farmers kept common carp in the ponds that fed their terraced rice fields. Carp are hardy, they tolerate cold and murky water, and in a regio…
Miners once carried canaries underground, and the cage wasn't just a cage. Some were fitted with a small oxygen cylinder and a door that sealed shut, so that once the bird showed signs of carbon monoxide, it could be revived rather than lost. The scientist John Scott Haldane cham…
Before anyone kept bettas for their fins, people in Siam kept them for their nerve.
Wild Siamese fighting fish are not the jewel-toned things you see in shops. They're small, drab, brownish-green, and they live in rice paddies, ditches and shallow floodplains — warm, still, low-…
Your ferret's name is a character reference. It comes, by way of Old French, from the Latin for thief — a small furred robber, caught in the act and named for it.
The label stuck because of the job. For centuries across Europe, ferrets were sent down rabbit burrows to flush the…
Guinea pigs can't make their own vitamin C. Neither can we. That shared flaw changed medicine.
Most mammals manufacture vitamin C in their own bodies — dogs, cats, rabbits, rats, all quietly brewing their own supply. Guinea pigs are one of the rare exceptions. Somewhere deep in…
In 1933, a laboratory ferret sneezed in a researcher's face — and proved a point nobody wanted proving.
Scientists at a London research institute were hunting the cause of human influenza. They had infected ferrets with material from sick people, and the ferrets fell ill in a fa…
Every office hierarchy you've ever complained about was named after a flock of hens.
In the early twentieth century, a Norwegian boy called Thorleif Schjelderup-Ebbe spent his summers watching his family's chickens. Not casually — he kept notebooks, named the birds, recorded who…
If you have a Syrian hamster asleep in a corner of your living room, there's a good chance its family tree leads back to a single wild burrow near Aleppo.
In 1930, the zoologist Israel Aharoni, working with the Hebrew University of Jerusalem, went looking for the golden hamster…
For centuries, nobody could say for certain whether a galloping horse ever has all four feet off the ground at once. The eye is too slow. Painters guessed, and mostly guessed wrong, stretching horses out like rocking toys with front legs forward and hind legs back.
In 1870s Cali…
In 1971, one of the newest American physics labs hired a ferret.
The problem was mundane: long stretches of pipe for a beamline, and no good way to clean the inside or thread a line through. The solution was a small ferret named Felicia. Fitted with a harness and a string, she r…
Before the plastic stick in the chemist's aisle, there was a frog.
In the 1930s, researchers found that if you injected a female African clawed frog with urine from a pregnant woman, the hormones in it made her lay eggs within about a day. It worked. Hospitals around the world k…
Every goldfish on earth is a colour mistake that someone decided to keep.
The ancestor is the crucian carp of East Asia: a stocky, olive-grey fish, perfectly camouflaged in muddy water. Every so often one hatched without the dark pigment and came out yellow or orange — beautiful…
In early 1900s Berlin, a horse called Clever Hans appeared to do arithmetic. Ask him four plus three and he would tap his hoof seven times, then stop. He answered questions about dates, music, spelling. Crowds adored him.
A psychologist named Oskar Pfungst tested him properly. H…
For decades, the British Post Office kept cats on the payroll. Officially. With a wage. It started in the 1860s, when the Money Order Office in London had a mouse problem so bad that letters and paperwork were being chewed. Rather than poison, the Post Office hired three cats…