My Bernese Mountain Dog surprised me today. I'll file this under the category of animals are never entirely, 100% predictable.
This big girl was obedience trained when I got her. She has one hole in her, that she dislikes sharing her territory with another dog. Certified to coexist well with any other critters and is a snuggle rug for my cats; it is specifically dogs who set her off. I've had her three years now, and her previous owners (who trained her) have done Schutzhund work (with other dogs, not on this one) and have trained many, many dogs over the years. They know what they are doing, and they did a great job with this one. She is SOLID on commands. She does not chase. Not once in 3 years have I seen her chase another animal, even a fleeing one that looked chaseable. I've seen her wish she could chase a few times, but the "thou shalt not" was obviously engraved in stone in there. Furthermore, at age 7 now, she is starting to slow down, stiffer getting up and down, just is starting to "act" older. They are notoriously short-lived as a breed, and 7 is the average lifespan.
So I was going out the door this morning. She was just as always, lay down when I put my hand on the knob, stayed while I opened the door and went out myself, waited for release before she stood and walked out the door.
Then she suddenly, about 3 steps outside, snapped her head up and took off like a bat outta hell. I have never seen this dog move that fast. It took me a minute to identify the cause. It was a squirrel, and she was gaining on him, too.
I have no great fondness for squirrels, but I didn't want her bitten by one in a death match, either, and I didn't especially want her to start considering smaller animals as snacks. Besides, they were heading for the road - idiot squirrel, could have picked a closer tree, but no, he wanted to run across the road. So I called her. She did break off the chase immediately, turned back to look at me (didn't come, just stopped and turned), and gave me the most perfect, "Aw, come on. Just having some fun" look. I called her again, firmer, and she came that time. Praised her when she arrived back at me.
I still cannot believe the speed with which she took off. Again, she's getting older, and she has never once chased anything in the 3 years I've had her. I guess something about that specific squirrel was irresistible.
Kudos to the original owners who put in a rock solid call back on her, but I have a new appreciation for how quickly things can happen, one split second, even with a totally trained and thought-to-be-predictable dog.