Once common throughout much of western North America, the grizzly bear species currently reside in five separate populations in western Canada, Alaska, Wyoming, Montana, Idaho and Washington; and there are around 30,000 bears in Alaska.
A rebound can last forever or a week. It completely depends. If you are already looking at the relationship as a rebound then it should end soon. You will not last with a person you feel is nothing more than a rebound to you.
That's not to say you can't feel 'in love' after three months of heavy dating, and it probably is acceptable to trot it out then. But for absolute maximum impact, I'd wait six. I know - hard core - but if someone says, 'I love you,' after you've dated for six months, they've thought long and hard about it. Saying, 'I love you,' when you're in the infatuated part of the relationship is easy: you aren't aware of any faults.