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Strange Animals Scientists Studied · Medicine

The Hamster Family Dug Up for Medical Research — and the Five Who Chewed Their Way Out of the Lab

On April 12, 1930, in a wheat field near Aleppo, Syria, a team of hired diggers followed a hamster burrow about eight feet into the ground. At the bottom they found a nest: a golden mother and her blind, hairless babies. A zoologist from Jerusalem packed the whole family into a box and set out for home. Within weeks the mother was dead, a pup had been killed, and five of the survivors had gnawed through the floor of their cage and vanished. The few that stayed behind would give rise to most of the pet and lab golden hamsters in the world.

By the Curiosities Desk · · 5 min read · Filed under Medicine · Today’s round

Part of Creatures That Changed Science

The Hamster Family Dug Up for Medical Research — and the Five Who Chewed Their Way Out of the Lab. Illustration.

What happened: The Aleppo Hamsters

The expedition started with a medical problem. Saul Adler, a parasitologist at the Hebrew University of Jerusalem, studied leishmaniasis, a disease spread by the bite of tiny sand flies. One form, called kala-azar, attacks internal organs and was a serious threat across the region. To study it, Adler needed lab animals the parasite could infect. Chinese hamsters worked, but they were hard to import and stubborn about breeding in captivity.

So Adler asked his colleague Israel Aharoni, the university’s zoologist, to find a local hamster instead. Aharoni was a natural choice. Often called the first Jewish zoologist, he had spent decades collecting animals across the Middle East and giving many of them Hebrew names.

Aharoni knew a golden hamster had once been described from Syria. A British zoologist, George Waterhouse, had named the species in 1839 from a single specimen, and almost nobody had seen a living one since. In the spring of 1930, Aharoni went to Aleppo with a local guide and hunter, Georgius Khalil Tah’an, who asked farmers where the animal might be. A local sheikh supplied laborers, and the digging in the wheat field turned up the nest.

Then things went badly in a very hamster way. According to Aharoni’s own account, the mother attacked and killed one of her pups shortly after capture. She was then killed herself. Smithsonian Magazine’s retelling says Tah’an put her in a cyanide jar, which left the pups with no one to feed them. Aharoni and his helpers raised the babies by hand on the way back to Jerusalem.

There, the pups went to Hein Ben-Menachen, who ran the university’s animal facilities. One night, five of them chewed through the bottom of their wooden cage and escaped into the building. They were never found. Later, one of the remaining animals killed another. That left three.

Ben-Menachen then tried something unusual. He packed a cage with hay so a female could burrow, much as she would in a field, and later introduced a male, her brother. The pair mated. Aharoni’s memoir calls it a miracle. Within about a year, the colony numbered roughly 150 hamsters.

Accounts still disagree on details. Sources give the litter as 10 or 11 pups, and Aharoni’s own writings disagree on whether the survivors were mostly male or mostly female. But the outline is consistent: a single burrow, heavy losses, and one brother-sister pair that kept the whole thing going.

Why it was strange: The Aleppo Hamsters

Lab animals are supposed to be the boring part of medicine, bred by the thousands in clean, predictable colonies. This one started as a rescue mission that nearly failed several times over, with escapes, deaths, and hand-feeding along the way.

It’s also strange that an entire species’ career in medicine rested on so few animals. Geneticists call this a bottleneck, meaning a population that passes through a tiny number of ancestors. The golden hamster went through one of the tightest bottlenecks of any domestic animal. That inbreeding later turned out to be useful as well as risky.

For another unlikely recruit to the clinic, see The Armadillo Pitched as a Leprosy Lab — and the Researchers Who Laughed Until It Worked.

What scientists learned: The Aleppo Hamsters

The hamsters did the job Adler hoped for. Leishmania parasites grew well in them, and in 1931 Adler and his colleague Oskar Theodor published research on Mediterranean kala-azar in the Proceedings of the Royal Society. Hamsters became a standard model for leishmaniasis and for many other infections. In 1939, researchers tested whether human leprosy could be passed to Syrian hamsters.

The colony also spread fast. Later accounts say Adler carried hamsters to England in 1931, reportedly in his coat pockets, where they went to the London Zoological Society. By 1938, colonies had reached laboratories in the United States. From there the animals moved into pet shops, and a commercial hamster industry grew up in the 1940s.

Modern research has corrected one assumption that came from the lab. In 2008, a team led by Rolf Gattermann tagged 12 wild female golden hamsters in southern Turkey and recorded when they left their burrows. Lab hamsters are famously nocturnal. The wild ones were out almost exclusively in daylight, mainly in the early morning and early evening. The authors suggested that the habits of caged hamsters may not reflect how the species lives in nature.

More creatures like this live on Creatures That Changed Science.

How it reaches us today: The Aleppo Hamsters

Golden hamsters are still lab workhorses. Their inbreeding means many develop heart disease that resembles human dilated cardiomyopathy, a condition in which the heart muscle weakens and enlarges. That makes them useful models for studying it.

In 2020, the species took on a new job. Researchers at the University of Hong Kong reported in Clinical Infectious Diseases that Syrian hamsters infected with SARS-CoV-2 developed lung disease resembling human COVID-19 and could pass the virus to cage-mates. Hamsters soon became one of the most widely used animals for testing COVID-19 vaccines and treatments.

And if you have ever owned a golden hamster, it almost certainly traces back to that burrow outside Aleppo. Scientists have since captured more wild hamsters to widen the gene pool, but the 1930 family remains the foundation.

A fellow animal hired for a medical job: The Giant Rats That Sniff Spit for Tuberculosis — and Get Paid in Banana.

Fun fact: The Aleppo Hamsters

The Arabic name for the golden hamster translates roughly as “Mr. Saddlebags,” after the cheek pouches it stuffs with food to carry back to its burrow.

Sources: The Aleppo Hamsters

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