Laugh if you want at this man's passion for bats, but the survival of tequila rests on his shoulders

As a kid, Rodrigo Medellin, star of Natural World: The Batman of Mexico (BBC2), kept vampire bats. Maybe they don't have guinea pigs in Mexico, but it meant the family home was full of blood. And bats became Rodrigo's thing: he has devoted his life to saving and protecting them.

Specifically, he's saving the lesser long-nosed bat right now. Also known as the tequila bat, because it pollinates the agave plant from which tequila is made. No lesser long-nosed bats, no tequila; now you understand how important it is. Imagine if there were a bat without which there would be no beer. You'd want it saved, right?

Saving tequila bats means working where they hang out. Caves, then, and hellish ones that go on and on, deeper and deeper, hotter and hotter, stinkier and stinkier, darker and darker.

The thousands of bats fluttering around Rodrigo's head aren't the only life down here. The floor is knee deep in guano – bat shit – through which Rodrigo has to wade. A kind of primordial super-concentrate, it's alive with creepies and crawlies and give-you-the-heebie-jeebies. Then there are cockroaches, millions of them, and the snakes, hanging out of holes in the wall, jaws gaping, waiting for something to fly – or step – in.

Anyway, next time you're having a moan about your workplace because it's a bit stuffy, or because so-and-so has BO, spare a thought for poor Rodrigo. Not that he's complaining. "The peacefulness in here is really overwhelming," he says in one cave, feeling the soft floor with his hand. "This is a bed of bat guano, I could just lie down here and take a nap, and it would be a very nice nap." And this cave is the one known as the Cave of the Serpents. It's actually more Indiana Jones than Batman.

Anyway, it's lovely. Not just because of the lesser long-nosed bats, which really are quite cute when you get to see them close up (still not sure about the vampires though). But because of Rodrigo. I think it's always better when there's a human story to intertwine with the wildlife: double-helix natural history.