I have had a Maine Coon, Jolene, for 5 years. She's been a a quiet, independent cat that had no problem exploring and lounging about our apartment.
Enter the new cat, Digby, a 2 year old male. We kept Digby in the bathroom for the first week, and then behind baby gates for an additional week so the cats could hiss and smell each other. We also would swap bedding, etc, so they could get used to each others' scents. In addition, we would allow each cat to roam the house while the other was locked in his/her own room.
Once we let Digby out to explore the house, Jolene hid under the bed. And has stayed there for about a month. Digby will occasionally crawl under the bed and harass her; if she ventures out, he'll cautiously creep around her until she turns her back for a split second and them BAM! he tries to pounce on her. When we feed Jolene, we lock her in the bedroom so she has some privacy and isn't scared to eat. She wants nothing to do with Digby and he doesn't seem to find her response acceptable. Both cats are spayed/neutered.
I very much do not want Jolene resigned to a life of hiding under the bed. Any suggestions would be greatly appreciated.