They are dewclaws.
There is a certain window that they have to be removed in (about 3-5 days of age); otherwise, they have to be anesthetized.
It's one of those things that some people agree with and some don't. My girl has them and if I had had the choice, I would have had them removed (in the 3-5 day period). Probably not worth it to get it done during spay/neuter because extra pain could go along with it, etc. It's really up to you. but I can tell you they are not thumbs, they do not use them to grasp with like we use our thumbs, and I'm pretty sure they never miss them.