Are rats instinctivly scared of the scent of cat?

Question
I have two female rats, normal, healthy happy, badly behaved. Very friendly, very playfull and very inquisitive. Normally. However last night I was at a friends house, and was playing with her three cats. When I came home my two rats were terrified. I at first assumed they must have smelled the cat on me, but now I'm uncertain. It does not seem to be me specifically (ie the origin of the scent) they are frightened of, they just seem to be sensing some extreme danger. They have calmed a little over night, but still have no interest in playing, only in hiding. Could cat scent on my have caused such a reaction?

Answer
 It's very possible that the scent of the cat caused them to act fearful.  Rats who are not used to other animals can instinctively be frightened of the smell of almost any other animal.  I don't think cat specifically is a scent they instinctively recognize, unless they had past trauma with a cat, but it's more that it is a foreign smell of an animal that is potentially dangerous.  Since rats are very low on the food chain it is natural for them to be wary of any other animal.

 If they are better in the next few days then there's nothing to worry about, but if they continue to act strangely there may be something else going on.  Keep playing with them and taking them out as usual, even if they're acting a bit jumpy, and they should calm down once they realize everything is all right.

 I hope that helps, good luck with your rats!