Season two of The Witcher hit Netflix late last year, giving us the chance to have a look at some all-new movie creatures (as well as Henry Cavill’s perfect chin). So in light of my love for a) invasion biology and b) top-class television (though I have to confess to sarcasm in this instance), I thought I’d traipse once more through the world of The Witcher and some of the concepts it brings up.

Read More: Biological Invasions & The Witcher

An Influx of New (?) Species

I say that we got to look at some all-new movie critters in this season, but given some of the character’s reactions, it seem like they’re seeing them for the first time too. Kim Bodnia’s Vesemir has a hard time figuring out the new Leshy’s biology, Geralt refers to the monster from episode six as “some type of Czernobog”, and Lambert’s response to Ciri bringing in some snake-headed chickens is “what the fuck kind of basilisks are those”.

This is probably a result of the limited number of each species that were a part of the initial introduction event. The world of The Witcher undwerwent a cataclysm approximately 1500 years before this show’s events, known as the Conjunction of the Ovoids. During this time a large number of species travelled between different universes, which is how many of the monsters we see (and the humans) ended up on this world.

A limited number would have made it across, and that limited number probably represents a limited gene pool, and a limited number of forms of each species – this is known as the founder effect. Those species are the ones that reproduced, and as a result genetic diversity was limited. The inhabitants of this world are used to only seeing a limited representation of each species.

This series introduces new immigration events, with the different worlds colliding more frequently, and new individuals coming through. Rather than new species, these are more likely to be the same species, but a different form than that which our protagonists are used to encountering.

On the plus side for these species, a new boost of genetic diversity would be a real help, since many of them are likely to be severely inbred at this point.

Are They Still Invasive?

Having been around for 1500 years, would these ‘monstrous’ species still be counted as invasive? By many definitions, yes. However there was a new framework proposed by Peter Banks of the University of Sydney for dealing with invasive species recently. It was put together as a means by which the status of the dingo on mainland Australia could be re-examined.

For those who don’t know, the dingo is considered native to Australia by most ecologists, despite the fact that it has potentially only been there for 4,000 to 5,000 years. With the Conjunction of the Discs only happening 1500 years ago, we’re on a tighter timeline, but let’s have a look.

Step 1: Has the introduced species evolved in its new environment?

This is a tough one, not helped by the fact that in the books many of the species we see are meant to be quite long-lived. The longer a lifespan, the less chance for evolution. Yet if the show is taking a more realistic approach to life histories, I’d still say there has been room for some genetic adaptation, and plenty of room for behavioural evolution. So let’s say it passes the first test.

Step 2: Do native species recognise and respond to the introduced species as they do other local species?

Here we may have to adapt the framework slightly, given the fantastical nature of some of the beasts. Perhaps we should be asking if the newcomers are being given the horrified recognition they deserve. I’m going to be a rank optimist here though, and assume that the local species do recognise most of the newcomers as a threat. The one exception being the first deer we see in the series, who really should not be hanging around bogs so brazenly.

Step 3: Are the interactions between introduced and established native species similar to interactions between native species?

Here’s where the introduced species’ quest for nativity falls flat. I don’t believe that species with such obvious evolutionary advantages as the Czernobog or Myriapod couldn’t have a distinct advantage when it comes to hunting down and preying on the native herbivores. Admittedly, most of the ‘regular’ species like the deer, fish, and birds we see seem to be doing fine, though admittedly it’s not exactly a priority of the show to investigate this. There’s no mention of game species drying up, however this is a pre-industrial world rife with forest, and I think that even if invaders were having a negative impact on the natives there would certainly be enough wilderness for them to maintain reasonable populations.

In all honesty I didn’t enjoy this season of The Witcher as much, in part because of the general drop-off in monster quantity. But I’m still hopeful for Season 3, whenever that rolls around.

If you want to hear more thoughts on biology in The Witcher, including some more in-depth looks at some of the monsters, check out our recent podcast episode!

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