Doggie vacation

Whenever we go away, our dog stays with my MIL -- she lives nearby and says she likes having him around. Oddly, every time we come home, our normally hyperactive (or at least periodically hyperactive) dog is exhausted. He often sleeps for days straight, waking mainly to eat and go to the bathroom. Last night, he was so tired, he didn't want to get off his bed to go outside before bed.

I think we finally figured it out. When we're home, he hangs out at home during the day by himself when we're at work, and I suspect he spends much of that time snoozing. At night, he hangs out with us, plays, and eventually goes back to sleep. When he's at my MILs, he spends the day hanging out with her husband, who really likes playing with him (or at least pretends to). At night, like when he's at home, he hangs out and plays. But when he tries to go to sleep, he spends much of the night hiding from the cats, two of whom love to torment him. By the time he gets home, he's way behind on sleep. Poor Buddy!

(This was a few years ago but, well, same basic dog.)