Yes I am convinced that ferrets can learn to purr, or something close to it!
 
We still had our cat Pepper when our first ferret, Belle, came into our
lives.  When Belle was very young, Pepper would tolerate her sleeping
curled up next to him.
 
As Belle grew older, when playtime was over, she would snuggle in our arms
and sigh contentedly.  As she grew drowsy, she would exude such contentment
and comfort she came very close to purring.  OK there was no actual rumble,
but her intent was clear.
 
After Pepper died, when Belle was about a year old, the almost purr
behavior gradually disappeared, though she has always been a cuddler.
Belle is now 7 1/2, on Lupron, Pediapred and Proglycem, sparsely furred,
pathetically thin, but still relatively active and content.  Alas she no
longer purrs, but still thinks under the shirt is the best place to be.
 
Linda Iroff
Oberlin OH
[Posted in FML issue 2939]