Did you know that the 8th-century Kingdom of Northumbria was the epicentre of an international exotic reptile trade? I only discovered this myself from watching episode six of Vikings (History Channel, Tuesday) and being introduced to the snake-pit maintained by King Aelle.

What particularly impressed me were not just the variety of pythons and boas at the bottom of the pit but also their excellent state of health. Somehow, the Northumbrians must have adventured as far afield as Africa, South America and Asia, captured the snakes, then learned to maintain them in optimal conditions, perhaps by inventing some early form of electricity to power the infrared lamps in their glass tanks and stop them freezing to death as they otherwise quickly would have done in the chilly clime of Dark Ages northern England.

At least I hope that’s the explanation. The alternative is just too depressing: that the makers of Vikings had so little respect for their viewers’ intelligence that they just went: ‘Sod it. Let’s just bung in any old snakes. It’s not like anyone’s going to know any different.’

Maybe 30 years ago that would have been true. Remember the snake-pit scene in Indiana Jones and the Temple of Doom? They were all constrictors too (apart, I think, from one random cobra, which was obviously behind a pane of glass), which made an absolute mockery of the notion that Indiana Jones was in any serious peril. Well, it did in my eyes, anyway. But I’m sure it went over most of the audience’s heads. ‘Euugggh! Snakes!’

Times, though, have surely moved on. We’ve since had two or three decades’ worth of specialist animal TV programmes in which intrepid presenters like the late Steve Irwin and Mark O’Shea have taught us a) to respect snakes rather than fear them, and b) to see them not as generic, slimy, bitey creatures but as distinct species (venomous types that kill their prey with poison; constrictors, which squeeze their prey to death). It’s not that snakes have completely lost their scare potential — I really wouldn’t want to go head to head with a taipan or a mamba — just that we’re all a bit more discerning about which ones constitute a real threat.

Well, I say ‘all’, but when I asked the Fawn whether she could identify the snakes in the pit she couldn’t. ‘How can you tell?’ she asked. So I think it could be one of those classic gender divisions — the female equivalent of that problem men have where we find it literally impossible to tell by looking at a woman whether she has had a haircut — even when she has mentioned that morning, ‘I’m just off to get my hair cut.’

But anyway, those snakes. If I’d been producing the series, what I would have done is made them all adders. Or maybe deadlier viper species from the Mediterranean basin. That way, when the man got tossed into the pit he would have been plausibly a goner and Vikings’ credibility would have been maintained.

I never meant to dedicate so much of this column to snakes by the way. But I think it does illustrate in a microcosmic way a problem we all have with our TV these days: series like Game of Thrones, Breaking Bad and The Sopranos have set the bar so high that it becomes increasingly hard to watch less perfect offerings without wanting to give up in disgust.

Why should I go on watching Vikings if it’s going to insult me with scenes as silly as the snake one? And if they’ve got that detail wrong how can I trust all the other ones about Viking customs and religion? The scene, for example, where one of the late Earl’s slave girls volunteers to follow him to the grave: is it historically accurate that her throat would have been cut for her by a white-haired priestess before she was laid next to him on the burning boat?

Still, if you’re looking for a reasonable GoT substitute — can it really be true that the next series won’t be out till 2016? — Vikings may, unfortunately, be about as close as you’re going to get. I’m also hearing very good things about Orange Is the New Black (Netflix), which I’ll report on in a few weeks once I’ve had a chance to immerse myself properly in its mix of prison, violence and lesbian sex. But I don’t think I’m going to bother with any more of Penny Dreadful (Sky), which ought to be a delicious League of Extraordinary Gentlemen mélange of steam punk and gothic horror but which — for all its vampires and monsters — seems achingly turgid in places.