Do male rats ALWAYS kill offspring.....

[sapphire_moon]

Does the male rat ALWAYS kill the offspring that aren't his?

I have 2 rats that appear to be pregnant, They are the same 2 in the "Introducing new females" post a few down.

Does the male ALWAYS kill any offspring that are not his? Or is there a chance that he will just let them be?

There has been no stress, they all pile one on top of the other. and actually had one of the pregnant females sleeping on top of the mother rat (that has the babies) as she was nursing! lol, I thought one had gotten out, but I could hear the babies. She was just lounging right on top of her and her babies. lol.
The male just cuddles with who ever is over in the corner he decides to lay in, he is about the size of an x-large rat, while the others are med and 1 small (the little 4wk old female).

So what do you guys/girls think?