...their ribs disconnect for a moment while they go through a tight space. The rule being: If they can get their head through a space, they can get their whole body through.

They may have gotten tired of dog harassment!

Yes, cats, *sigh.* On the other hand, when I think of how fast rodents breed (I think that I heard the other day that them, their children, and children's children can up the rodent population by 2,000 in 1 year - just 1 pair!), and how many the cats catch...well, these days just Uhura, I guess that it's better than letting them just breed willy nilly!