Cleve, our 10 year-old German Shephard/Husky mix, is starting to show agressive behavior towards our other three dogs (especially towards Roy, a two year-old Chocolate Lab). Cleve has been a bit grumpy at times for the past six months, but this week has been going after Roy and the others. This is not aggressive play, but trying to grab Roy by the neck. This started happening last week when I laft on my current trip.

My wife has been keeping Cleve separate from the others, and he's been fine alone. If he sees Roy, Cleve starts to growl. Cleve just may be getting old (he was diagnosed with cancer a year ago) and tired. Cleve shows interest in a toy I recently bought (he can't be separated from it), and still loves to eat.

Any suggestions/ideas from anybody?