Mine are nuts about KONG "Squiggles" toys. I finally threw away their first one after about two years' faithful service. Bought them a variety of new toys a few weeks ago and the new "Squiggle" is the clear favorite. They are obsessed. My guess is its dangly-ness is reminiscent of a dead rodent. The small size is perfect for them.

www.amazon.com/gp/product/B002UCYGWE

edit: I would add that the MultiPet brand loofah dogs (you know, the really long dog-shaped squeaky toys) are crap. They've had durable ones in the past but the MultiPet sucks. They killed it in 5 minutes, no joke. They are not usually destructive chewers.