Rats! It's Philly's Biggest Export

Philly's Biggest Export is Pretty Small

Guess which Philadelphia product has sold more than any other – millions of unit?

Clue, it’s actually an animal and like the Labrador retriever, the Bengal tiger and Shetland pony, it’s named for a place – a place in Philadelphia.

You guessed it – a rat. 
It’s a rat that was bred right here in West Philadelphia: the pure white Wistar rat.

Unlike the nasty rats that spread disease, the albino Wistar rat is gentle, cute and extremely useful to medicine. It was probably the first animal bred for laboratory use and can claim to be the most numerous lab animal in the world.

Scientists at the Wistar Institute developed the albino rat in the early 1900s. They carefully bred the rodents in order to get consistent, accurate results from medical experiments. So, they all have the same size, physical characteristics and genes.

Wistar also made money by selling their rats to countless other labs. You can still buy pure-bred Wistar rats from several breeders around the world.

Today there are other strains of laboratory rats but the Wister rat is still the most popular rodent in medical labs.