I took the following video over the course of several days, and finally put it together this evening. They're about three months old now. :)
Also, I have good news about Sabine, who I thought was having seizures!!!
She had another "seizure" yesterday and I looked up more info online. Someone had suggested that she might just be in heat, so I looked up videos of rats in heat. Guess what I found? A female rat in heat doing exactly what Sabine was doing.
It was such a relief to find this. Whew. Panic over. :) It's just funny because I've never seen a rat do this before, and I've had female rats in the past. I guess they react differently to being in heat, just like human women have different PMS symptoms.
Also, as they've aged there is now a new way to tell them apart. It used to be that the only difference was that Beka had a white tip on her tail and a white spot on her belly. But these days Sabine has a dark stripe on her head and Beka doesn't. So now I don't have to look at their tails or tummies to figure out which is which! :)