I could have told you that !
My friend at Ales Rarus sent me a link:

Cunning rat outsmarts scientists:
Rodent eludes capture for 4 months

I was particularly amused by this...

" eliminating a single invading rat is disproportionately difficult..."
Well, duh. I've had problems getting a baby domestic rat out of a recliner. Getting a wild adult rat off a whole island ? No wonder it took four months !

Fortunately, domestic rats usually want to come to you !