I am new to this group. Here's a little history... I adopted two young cats from a shelter about 1 month ago. They are sisters from the same litter and they are about 1 yr old. They are adorable and lovable. They typically play well together, however it seems that more and more their play times turn fiercely aggressive. They get into a ball, hissing, howling, screaming, and "kangaroo kicking" each other's faces while holding tightly to one another... so as not to let the other get away. These fights are horrible! I fear that there will be serious injuries to their eyes. I work during the day, so I am not certain whether or not they do this while I'm gone, but it is relentless while I am at home. I am concerned that jealousy may be an issue, however I am at a loss as to how to handle this. I give them both equal attention. Does anyone have any ideas as to what I should do?