Growling Mini Schnauzer

Question
My husband and I inherited my mother-in-law's 3 year old mini schnauzer in April when she died.  At first he was very sweet and playful, but now he has started growling whenever we pet him and he acts like he might bite us although he hasn't yet. We moved into her house so he hasn't had a change of surroundings but we have added our 2 cats to the household.  We love the little fellow but I'm beginning to get afraid to play with him.  

Answer
First I would have him examined by a veterinarian to be sure that there are no pain issues going on, but whatever is found (or not), it is time to get the boy into on-going obedience classes and to start practicing Nothing in Life is Free with him. (http://k9deb.com/nilif.htm)

He is becoming a mature adult, and it is not uncommon for some to start asserting themselves at this time, particularly if they see an "opening" with owners who are inconsistent in being Alpha.... and schnauzers are the WORST for this. Someone *MUST* be Alpha in the family "pack", and schnauzers are more than willing to accept that job if the owners are not (in the dog's eyes).

Karen