I have a 7 1/2 month old wired hair jack russell female and a 4 yr old min pin male well I just got the jack russell and have a appt to spade her so I don't have puppies I been really careful not to let them near each other don't want puppies and today my son let them out I found my min pin humping her could she get pregnant?

Yes. I suggest calling the vet and getting her spayed next week.

Keep them separated!! Is she in heat? Was he just "humping" her or did he penatrate her?

Is she in heat??

That's what I was thinking Lucky, unless you Jack is in heat no, she can't get pregnant.
Dogs often hump each other to assert dominance, it's not necessarily sexual.

How far away is your spay appointment?
If it is in the next week or so then just go ahead with it, pregnancy or not.

No my jack russel is not in heat she has never been in heat yet... her apt is in 2 weeks... should I bring her in to be checked?

I don't think you need to.
If you are positive she isn't in heat (which would be unlikely at 7 1/2 months anyway) then there is 0 chance of pregnancy.

Even if she were in heat and did happen to become pregnant, they can still spay after 2 weeks.
If you want you can call your vet and let them know what happened, see what they think, but I think you should be fine.

I agree, if the pup wasn't in heat, then she was never bred. Humping is dominance, like Shazzy mentioned. Its also signs of an unsocialized dog with other dogs. If you've been keeping them separated, that was his first response to her. Next time she may lay down the rules ;)

Typically dogs will not allow other dogs to hump them unless of coarse it is for breeding purposes. Puppies go through a humping stage that they need to go through. If your boy didn't have that opportunity, then that is more then likely why he humped your girl.

If she wasn't in heat, then don't worry about it. When a female is in standing heat, its very hard to miss!

Thank you everyone for your help