These Russian seals were last seen 6 or so years before this strip, rowing their way out of the swamp. Their boat was their space capsule that they had landed in weeks before (according to Albert "approximately at 5:02:24 PM, EDT on September 13, 1959").
It's funny (and ironic) that even though they had landed in the Okefenokee, they were convinced they had landed on the moon, like our boys will be convinced they're on Mars.
They left in a hurry because one of them ran into the mailman 'up here on the moon', and he told the seal that "at Christmas time these people sell seals. Christmas Seals, they call em." "What!?" the other Russian seal exclaims, "That's slavery! Let's get out of here."