Vector, my 6-year-old rescue dog, was suddenly acting twice his age.

He was wincing, doddering, balking at easy jumps on and off the couch. His back was hunched, his gait narrow and tepid. He wasn’t even greeting his favorite human at the front door upon my return from work.

“Not again,” I thought, kneeling over to caress Vector on the living room floor.

I’d barely crouched down when a rolling blur rounded the corner from the dining room. At a speed seemingly impossible for a 13-month-old to reach, my human son, Nicholas, was bearing down on Vector in his walker – an infant Fred Flintstone about to mess up Dino’s day.

I managed to scoop up Vector a split second before his baby brother’s attempted fratricide. Instead of Vector’s head, the walker slammed into my knees. Nicholas shrieked with laughter while I groaned in pain.