Are pet store rats really discarded lab rats?

I’ve heard that rats sold in pet stores are lab rats that are no longer needed by the labs. Is that true?

Hardly. Rats are easy to keep, easy to breed, and make good – even affectionate – pets. They’re also quite clean, given reasonable caging conditions. Lots of people with pet rats produce “extra” offspring that make their way into the pet trade.

Lab rodents are often sacrificed as part of whatever test or experiment they’re part of. And there are many varieties bred for specific genetically based characteristics (e. g., failure to utilize some specific vitamin or enzyme) and are far too valuable to be dumped onto the pet trade.

Also, one of the more common traits they breed into lab rats is for them to have virtually no immune system to speak of. They don’t last long as lab rats, and they wouldn’t last long as pets.

Occam’s razor: Pet rats are quite a bit cheaper (barring some fancy rare breeder), and typically come in more colors than lab rats (e.g. Wistar, Sprague Dawley are white). Lab rats have been specifically bred for certain traits. Meanwhile it is not difficult to make more pet rats if you need them; mood lighting not required.

You must be a biologist. I typed one of my wife’s papers when she was in grad school, and I figured biologist must be very religious, seeing how much they sacrifice.
She got her rats from a specialty house, and I’d suppose they were more expensive than pet rats.

Lab rats are often needed at a specific age range or sex or bloodline, so breeders are sometimes left with excess inventory that they can’t sell to a local lab. So those sometimes get sold into the pet market. But lab rat breeders don’t like to do this, because they have to sell them at a greatly reduced price.

Cite? Many lab rats will be handled by scientists which are basically regular people with regular germs on them. And many experiments involve surgeries. “General purpose” (Sprague, Lewis, etc) rats are solid; no one wants them to die as soon as they get a bug.

Perhaps the person who told you this was half remembering that the pet breeds were originally lab strains

I worked at a research facility in Bethesda, MD.

Our lab rats were inbred for 25 generations, before we could experiment with them. This was done so they had the same genetic background. Other labs bought them from us. But they were very expensive. None to pet stores.

Their common name was “Cotton rat”, I don’t remember their scientific name. We used them because they were the only non-primate that would host the virus we were researching.



The Cotton Ratis Sigmodon hispidus. That’s interesting. I wasn’t aware that they had a special susceptibility to human pathogens.

The common lab and pet rat is a form of the Norway or brown rat Rattus norvegicus.

The virus we were researching was RSV.

There are a certain number of lab rat rejects that don’t quite make the cut for various reasons and end up being used elsewhere. In this city the local university donates them to the wildlife rehab center/s to be used as food for the birds of prey.

I know this because I contacted those centers recently hoping to make some money breeding rodents to sell them… nope sorry they already get free high-quality rats from the university. Also during my research I saw that tons of people breed rodents and sell them online alive and dead… it’s pretty hard to make any kind of money selling rodents because they’re just so damned easy to breed and raise. So it’s not like the pet industry is hard up for supply and has to take weird red-eyed lab rejects…