Better yet, hang a note on yer front door that says:

Del & Dale,

Sorry if I've missed you. I had to take the postman to the hospital 'cause my new pit bull, Killer, chewed him up pretty good. I'm pretty sure it was just a fluke 'cause Killer usually only eats cats. He's prob'ly only bit three or four other humans.

Anyway, Killer's inside the house. You guys know where the spare key is. Go ahead and let yourselves in and make friends with Killer.

Be back in a few hours.

G