Intraspecific Competition and Cannibalism

This is a smaller thing I’ve been meaning to get to for a while, so let’s start discussions. @Oliveriver created a branch with working cannibalism about a month ago I think, but there are some design questions remaining that we should wade through before we see cannibalism properly implemented. Oliveriver initially implemented cannibalism as a togglable starting game option that would essentially allow cellular friendly-fire. While that definitely could essentially be a Thrive equivalent to a hardcore setting, since cannibalism is an actual evolutionary trait exhibited by some organisms, we should probably find a way to implement it more rigorously and dynamically within the base game itself.

In my opinion, I think we should make it so that cannibalism is easily avoidable by a player if they don’t wish to worry about their own species killing them. So we can implement it as an option in the behavior tab. But we also want to allow the possibility of organisms who can consume their own kind, but only do so in severe conditions. So we probably want some sort of aggression/sociality slider? The more social, the more likely the organism will stick in clusters and bind to other cells, while the more aggressive, the more likely the organism will isolate itself and prey on others of its own kind. That leads to some questions and awkward areas: what if you have the toggle fully set to aggression but cannibalism is off? At what point on the slider will your own kind actively hunt you?

There’s some kinks to iron out (effects on auto-evo for example), so I wanted to open the discussion on the forums. I’m sure we can land at an intuitive concept very quickly and implement a pretty interesting behavior to spruce up gameplay.


I think only the slider should be added. Because as you noticed it leads to easy exploits if you can exploit the behaviour of cannibalism without getting the drawback of your other cells attacking you.

I think we 100% need some serious drawbacks in both the gameplay and auto-evo for cannibalism. After all we don’t see literally every species using cannibalism all the time on Earth. So we want to make the tradeoffs so that it’s not an option that would be a no brainer to pick each game.


My concern with a slider is that it’s a bit opaque for the player. If my species is 70% cannibalistic, how much care should I take to avoid them? What’s the threshold for when I can hunt other members of my species? A slider would be better for Auto-Evo stuff though, since models seem to often use the continuous parameter “cannibalistic tendency”.


We can have it so that damage towards and from one’s species is enabled once the sociality slider is set towards the aggressive half. Note that this slider would have Social on one end and Aggressive on the other (so Social ————— Aggressive). Once the player is on the aggressive side, damage is toggled on. This allows players who don’t want to worry about their own species attacking them the option to completely avoid friendly fire.

Then, I have an idea that damage towards your species can be debuffed depending on the sociality level of your organism. So if your species is 10% aggressive you’d do 10% damage, 25% aggression means 25% damage, etc. This makes sure players aren’t able to exploit preying on non-combative prey as easily, since they’d similarly be debuffed. It also allows, say, an organism which isn’t cannibalistic but is territorial over food sources. That could lead to intraspecific competition as a behavior.

We’d have to go a few steps further to completely ensure that cannibalism and competition can’t be exploited, but that could serve as a good basis.