They Just Want to Make Sure I'm Paying Attention

So I'm flipping through my German grammar review book, trying to remember how to express the tense "to have been", when I come across this rather random verb valency chart. I really can't figure out what the point is, or how they chose which verbs to include, but that is now well besides the point, because I can't get beyond the first example in the chart:

Der Nackte Affe hat den Penis/das Hirn.

Let me translate for you friends:

The naked monkey has the penis/the brain.

Pardon?

First of all, why not "a penis"/"a brain"? Whose penis does the naked monkey's have? His own (the penis of the monkey)? The zookeeper's (the penis of the zookeeper)? And wouldn't the monkey have a penis regardless of being naked? In fact, when is a monkey not naked? Do the grammarians want to clarify here than we're not talking about one of those Bedtime for Bonzo showbiz chimps? Or were they counting on the fact that no one would probably make it all the way to page 137 of Essential German Grammar?