It wasn't immediately obvious what to review today. I'm looking at secrets – of the Vatican, briefly, but first Secrets of Bones (BBC4), with Ben Garrod, an affable sort of chap you could easily imagine having a pint with. A bit like Jimmy Docherty, but Ben actually has an area of expertise. More like George the Restoration Man perhaps. Ben the Bone Man.

Does television really have the need for a full-time bone man though? Maybe not, but then Ben does other things. Well, he articulates skeletons – as in he puts them together, for museums, universities etc, he doesn't just say the word, clearly and coherently, over and over again, until the phone rings from the BBC.

We've reached the end of this absorbing little six-part series, and Ben's ending where it all begins: sex. Specifically, on how the skeleton can help with that. Yeah go on then, better get the obvious out of the way: bones, boners, fill in your own blanks, make your own joke, teehee. In fact, 86% of mammals have actual bones in their boners (I'm guessing – hoping – that's 86% of male mammals). Which is why you never come across an impotent walrus (proud owner of the biggest penis bone). No Viagra necessary. The Walrus and the Carpenter (who presumably also has no problems getting wood) suddenly takes on a whole new meaning, especially after eating all those poor oysters.

But before getting down to it, making sexy time, vertebrates have to find and attract mates, and bones play their part in this too. A male gorilla, for example, has a prominent ridge on top of its skull to which its chewing muscles are attached. But it also looks pretty cool, lady gorillas dig it, hopefully enough to chose to reproduce with Mr Big Cresty Head.

Closely related (95-99% DNA-wise) to the gorilla, of course, Ben himself has a muscle, presumably attached to his skull at some point, which he uses to raise his left eyebrow, flirtatiously, when he talks of sex. I imagine this could have a similar effect to the gorilla's ridge on potential partners. When you throw in a collection of skulls at home to come back and have a look at … well, put it this way, I think Ben's own DNA is 95-99% guaranteed a future, if that's what he wishes for.

For a mandrill, long of tooth is a good thing – less than 3cm and they can forget about getting any. The mysterious narwhal may use its magnificent tusk as a sensory organ, a sort of sonar for tracking down girl narwhals in frozen oceans. And male bighorn sheep smash together their big-horned skulls, which are stitched together for extra strength like a baseball, to impress potential partners. Accompanied by a heavy metal soundtrack ...

Oh yes, just the one tiny moan: the music. It's a bit corny and hackneyed. So a pair of chameleons do battle to what sounds like the film score to a western – The Good, the Bad and the Scaly maybe? Flamingoes and birds of paradise dance to a sexy Brazilian bossa nova. And the male fighters – the antelopes, hippos, polar bears etc – they rut away to Ace of Spades by Motorhead. Oh, I see, they're headbangers, is that it? So maybe those sheep should have clashed to some chords by former Oasis's guitarist Bonehead. And then, for the victor, I Got Ewe Babe … shut up now.

Secrets of the Vatican (Channel 4) are more sinister ones. When a puff of white smoke signalled that the reforming Pope Francis had been chosen last year it was barely discernable through the black cloud that hung heavily over the Vatican. A cloud of paedophilia and child abuse, corruption, lying and cheating, financial scandal, cover-ups and hypocrisy: the cloud that saw the eventual resignation of Pope Francis's predecessor, Benedict XVI, the first pope to do so for 600 years.

This documentary isn't really breaking anything new. But still, presented and packaged like this, with firsthand testimony – from insiders, victims, investigative journalists and police – it paints an extraordinary and damning picture of a rotten institution. Basically it's The Borgias, Neil Jordan's drama series with Jeremy Irons as Pope Alexander, only in the 21st century and all real. The Church of the Poisoned Mind by Culture Club, if we're still playing suitable soundtracks … We're not? OK, and I'm giving away my enormous age.