I don't want to be repetitive so if you are interested in in the possible development of the whelps go back to the posts from September 2010. Additionally, I've copied in the info below just because I think it is interesting. (I apologize for any misspellings. I just copied it from a website )
I've put the chart off to the side so that it is there throughout the pregnancy and you don't have to go back and forth to see it.