American Fancy Rat & Mouse Association

This article is from the WSSF 2015 AFRMA Rat & Mouse Tales news-magazine.

Breeding & Stuff

Temperament: Natural or Selection

By Karen Robbins

Marlene Miller, D.V.M., Texas
Ed. Note: Marlene had rats from another breeder when Jozzette Hagemann moved from California to Texas in 2014. Jozzette sold rats to someone in Texas that already had rats and one of their existing rats bit the tail of one of the new babies. The babies were returned to Jozzette and the one with the bit tail went to Marlene to have the tail fixed but it ended up having to be amputated. The rat was to go to one of the vet techs but Marlene ended up keeping the rat for herself after the surgery. She tried to integrate him in with her other rats but they had respiratory issues which Barkley got, as well as temperament issues, and he never really got along with them. So, she euthanized the sick ones and got new babies from Jozzette.

Q Barkley is the black baby I got from Jozz that I amputated a portion of tail and ended up keeping. It turned out to be the best thing that ever happened to me because I really had no idea what a really well bred rat was like. Barkley is out of KK and JRPR lines. Not only is Barkley pretty but he is super smart, loves to play games, naturally picked up coming to me by name, super affectionate by constantly licking my fingers and hand especially when we greet each other (not just for food). Are all your rats like this and do you select for it? How would you know the ones to breed? Are English rats even better?

I had a Hairless rat but he was making no real progress after many hours of working with him. I knew that even if he would get over his terror of handling he would be a possible carrier of myco. My goal is to be able to bring my show rats home with me which means they cannot be exposed to any other rats between shows. Barkley is on a regimen of doxy and Zithromax daily and only has an occasional sneeze. I believe the Hairless was a carrier.

A I’ve been breeding rats since 1974 and I learned early on that temperament is part of breeding rats—if they have bad temperaments, I don’t keep them. If a mom was protective of her babies, I got to the point of not tolerating that after one flew across the cage to try and bite me when I was not even close to the nest! I’ve always liked rats with personalities and they always seem happier than the shy ones. I’ve also learned that since temperament is genetic, then really young babies are a lot calmer/more tolerate of handling when bred for good temperaments and don’t need massive amounts of handling, where the really squirmy, run for your life when they don’t have their eyes open ones don’t get better and those are not kept. However, breeding two nice temperament rats doesn’t always mean you will get nice kids (especially if you don’t know if there is aggression in the background). There was one breeder I knew who bred two nice rats (one from a pet shop), handled the babies daily, and they were all extremely aggressive and bit when they were only 3–4 weeks old (right after opening their eyes). Needless to say they were all put down. I’ve also had the experience that aggression can skip a generation. There are also those in a litter occasionally that are shy/hide at 4–6 weeks (they will also sometimes bite) where the rest of the litter is at the door wanting to see what you have—these out of a line of nice rats and all handled the same. Some breeders don’t put those down, just sell them, where others (like me) put them down as they don’t make nice pets as their inherent nature won’t let them; they definitely should never be bred.

I’ve also had rats that as little babies will tense up and scream when handled. I’ve kept some of these to see if they get over it and some will, but even those that do, will later be back to the don’t touch me/handle me and screech when picked up.

I’ve also been able to tell by handling a rat at a show if it is happy/nice. One kitten I judged a few years ago was OK on the first handling, but the next time I went to look at it, it bit me (not the kitten tasting/nibbling, but biting; the owner was there when it happened) and had an aggressive/mean look—kittens should never be like that. I was shocked to learn it was sold then as a pet. There have also been other rats that I can tell by looking at them they aren’t happy/nice and those invariably end up being aggressive/biting and having to be put down (or should be in my book!). One rat at a recent show was fine handling (no squirming, squeaking) but later when I heard it bit the new owner, I remembered it had seemed a little off that day. There are also those rats (males) at a show that are aggressive, puffing up, would bite if I let them/ wasn’t careful, that I always comment on them needing to be put down or neutered and the owner a lot of times will say they are fine at home and it’s because of the show and other male rats here. Well, the other male rats at the show did not do that, so that is not an excuse to breed bad temperament rats.

Another thing with rats, if you put a shy rat with a nice, outgoing, friendly rat, the shy one will learn from the friendly one. It may not turn out to be as outgoing, but it will see that there is nothing to be afraid of.

There have been studies done on tameness (temperament) showing it is genetic and we have a Temperament/Tameness section on the Links page of our web site. Some of the articles are:

There are also several articles by Eva Johansson in Sweden where she points out the difference between being tame and having a nice temperament.

My mostly English ones have nice temperaments/personalities, they are just different (usually not as calm as some of the marked ones but still nice rats) (these are my rats; others from England may be completely different). If they (or any other rat) are really squirmy, I don’t keep them. I’ve also had rats that start out nice, but as young adults suddenly run and hide when you open the cage and don’t want to be handled and will screech when you go to pick them up—those go as well. I did have one English guy I brought in in the 2004 shipment that got to where he didn’t like other rats (females) but I didn’t put him down because I liked him. I did breed him once and carefully watched the line but none had his issue. On the other hand though, I brought in a young male in the same shipment and put him with one of my young males the same age and they got along great until they hit 4 months when suddenly the English guy then tried to kill his cagemate. He DID NOT stay!

As far as kissy, my rats are not like that here, not that I wouldn’t want to breed for that. I have had some over the years like that but not all the time. It is all dependant on how much time an owner puts into the rat to bring out the personality—the more they are handled, the nicer they are if the genetics are there. I think Barkley knows you helped him.

Update: It seems as though rats (like people) can have very similar genetics but dissimilar temperaments and intelligence. I’ve been looking into how much intelligence in rats is linked to genetics and apparently there is a line of rats called Long-Evans that is of superior smarts. The strange thing about Barkley is he had a rough start with his injury and surgery yet always remained well adjusted and friendly. I’m sure that another big part is having a doe that is a good mother that provides a lot of licking and contact early on [one interactive site Ed.]. I believe that is connected to brain development and socialization later on. I also wonder if temperament and intelligence can be linked to coat color and phenotype closest to original. It seems in dogs when you start breeding for varied sizes and colors, it weakens what the original was. Most original colors were Black and Tan, red, brown. They started breeding in all those weird colors like dapples, Merles, piebalds, and I can attest it changes the breeds original personality for worse. I am very, very thrilled to have experienced Barkley who is a product of your breeding program. He is a delightful beautiful rat who has brought me much pleasure. Marlene Miller *

January 1, 2019