My sister and her husband have had one for years now. It’s a great, great dog. It’s extremely intelligent and very well behaved. It has a lot of energy - I’ve never seen him get tired of catching a frisbee - but it can also be extremely lazy at times. My sister’s never had problems leaving him home alone for hours at a time. The dog is older than their child, and he’s been great with my nephew. They’ve never had a problem with that, even when the baby was pulling on its ears and whatnot.
The only way to describe the way the barn owner’s JRT chases and barks at the barn cats is “unrelentingly.” They have incredible high prey drive for anything that runs. When the cats stare the dog down, it doesn’t chase… just barks without ceasing for hours.
Can you tell it drives me crazy? In my observation, JRTs that can cohabitate peacefully with cats are the exception, not the rule. It helps if the cats are clawed and aggressive. The only cat the JRT doesn’t chase or bark at is the Barn Owner’s Maine Coon Cat, who is larger than the dog and once ran it down and kicked its ass.
Hounds and terriers are of different temperments. Hounds, when on a scent go after anything and usually have tremendous stamina in the feild. At home, most are homebodied, gentle souls who enjoy lazing about in a heap. Most are good-excellent with children and other dogs.
Terriers, are tenacious and can have issues with other dogs and kids. Not all and each breed has its quirks from overbreeding and whatnot. I would love to get a couple different terrier types, like Border Terrier or a Scottie.
JRT’s are referred too by my Professional Dog Training Neighbors ( who do those agility shows and flyball and are sponsored by Eukanuba and their dogs are seen on TV nationwide.) Jack Russell Terrorists.
They have two JRT’s, and while they are intelligent, responsive and full of energy, they are, most of all, full of energy. I stood with this guy as he had a ball chukker ( it allows you to throw a goobery tennis ball about 5-10 x’s farther and not touch said goobery ball.) and he neverstopped throwing the ball for his two JRT’s for over two hours and the dogs never tired. It was enough for me to enjoy his dogs but never want one. Even though they are soooo cute.
All his dogs are very socialized and he has a bunch of breeds ( dobermans, aussie’s…) and whenever there is a skirmish…there is a JRT in the middle of it and the other one will not hesitate to jump right into the thick of things. He said if those dogs were humans they would be italian commandos. short, tough, tenacious little buggers.
More info on JRT’s
Other breeds that may be of interest and are popular with women. And if anyone wants to buy me any one of these, I would gladly accept. 
and naturally, there are loads of dogs that need a loving home, Petfinder
Jack Russells were breed to chase small furry animals, and as such will chase your mum’s cat, as will most terrier breeds.
I had a couple of rat terriers. They were a hand full. Extremely full of energy. They fought with each other all the time. They chewed anything in sight. They loved rolling around in fresh piles of shit. They were really intelligent but had minds of their own. At night they slept for no one but me. My mother hated it when I stayed out. She wouldn’t get any sleep until I got home.
I always thought that bit of character naming was incredibly inspired.
All true, but as a group they are NOTORIOUSLY difficult to train, which is what I was getting at. Ask any obedience club what they shudder to see walk in the door, especially if it’s from the “sight” rather than the “scent” branch of the family.
Good point on the hounds and training. Each breed has developed for their own specific reasons and will have strenghts, and drawbacks. It is imperative to review all these and meet with owns of the breed and spend some time with one before committing to any dog ( or pet) .
It isn’t fair to the breed, the dog or yourself if you (yes you) buy a cutesy poochie because it is The Thing that is so trendy right now and Paris Hilton carries one around on her arm. Remember, she is a rich flakey twit. You (yes you) are capable of making informed, rational decisions about what pet is suitable for your lifestyle and needs.
/soapbox.
Well, since everyone else has already mentioned that JRT’s are hyper, I’ll just add that they are very hyper. There’s a commercial that I always laught at because it’s so true, it shows a Jack Russel jumping up and down over and over again.
I do not think this breed would be good with the elderly cats either. They are rather hyper and would much enjoy chasing them around the house much to the cat’s dismay.
Terriers can be rather feisty as well and it could turn out to be a biter of people. They are also rather hyper.
Have I mentioned that they are hyper?
Someone mentioned greyhounds. Not exactly small dogs and yes they can be very mellow, however some are cat-eaters and I wouldn’t recommend bringing one into a home with cats without knowing it’s preference.
Honestly, I think her best bet would be a mixed breed.