An ape went into a bar with its human master. The bartender told the guy to keep his ape away from the pool table because the balls were ivory and now impossible to replace.

Well, the ape went to the table, picked up the cue ball and swallowed it.

The bartender threw them out with the admonishment 'never to return'.

Two days later the fellow and ape entered the bar. The fellow was carrying a small box that was gift wrapped. Bartender told them to leave but the fellow gave him the box with sincere apologies. Inside was the cue ball all white and clean, sparkling. So, the barkeep told them they could stay but to keep the ape away from the table.

As the evening wore on, the ape would take pieces of pizza crust and shove them up his arse, take them out and eat them. Same with crisps, peanuts, celery, etc.

The barkeep asked the fellow what the ape was doing and the fellow replied, "Well, ever since he passed that cue ball he's been checking the size of everything he eats!"