Zoology: Realistic Animal Overhaul
Overview
[b]Zoology[/b] is a comprehensive animal overhaul that maps in-game animal performance to real-world biology without breaking gameplay. All vanilla animals plus those added by the official DLCs have had their core stats recalculated from biological inputs — average body mass, gestation period, litter/clutch size, claw & tooth dimensions, bite force, growth rate, and more — assembled from scientific literature and automated into the mod’s data pipeline. The mod balances these more realistic numbers against RimWorld’s in-game formulas so animals feel stronger and faster in a way that still fits the game.
What’s changed
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[*] [b]Complete stat rewrite[/b] for every vanilla animal and animals from the official DLCs. All core stats (body size, gestation period, litter/clutch size, bite force, etc.) were compiled from scientific literature and converted into in-game parameters. Forget about omnivorous monitor lizards gobbling up your rice or bloodthirsty ostriches with a 100% manhunter chance on damage.
[*] [b]Animal sounds[/b] have been improved. Say goodbye to meowing cougars and tigers.
[*] [b]Ecology & distribution tweaks[/b] — animal distributions in biomes have been adjusted to remove glaring inaccuracies (e.g., tropical reptiles in deserts or wild alpacas).
[*] [b]Misc fixes[/b] — birds flee using flight rather than ground sprinting; cold-blooded animals (reptiles, crabs, snails) suffer metabolic slowdown in cold rather than vanilla hypothermia mechanics; removed guinea pig fur; and other biological corrections.
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Optional, configurable mechanics
[b]Zoology[/b] offers many player options so you can pick realism without sacrificing fun. Every major behavioral change can be enabled or disabled via config to suit your preferred playstyle or to help compatibility testing. All of the below are optional and configurable via in-game settings:
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[*] [b]Advanced predation logic[/b] — predators choose their prey based on size, kinship, age, and combat power (with less emphasis on raw body size) if [i]Enable advanced prey selection logic[/i] is enabled. Pack hunters can initiate group attacks even if not all pack members are hungry when [i]Enable pack hunt behavior[/i] is enabled. Large mammalian predators prefer larger prey. Snakes and frogs now swallow prey whole and can no longer chew corpses.
[img]https://i.ibb.co/k2KGvftk/Predation.gif[/img]
[*] [b]Prey fleeing[/b] — prey species attempt flight from hunting predators; predators will abandon pursuit if they cannot catch their prey within some amount of time. Controlled by [i]Enable prey fleeing from predators[/i].
[img]https://i.ibb.co/BHFYfg2C/Chase.gif[/img]
[*] [b]Custom flee-from-danger override[/b] — replaces the vanilla [i]ShouldAnimalFleeDanger[/i] with a scalable system controlling animal responses to threats on their home maps.
[i]Safe Predator Body Size Threshold[/i] and [i]Safe Non-Predator Body Size Threshold[/i] determine which animals consider raiders and other dangers worth fleeing from.
If [i]Animals flee from humans[/i] is enabled, animals may also flee from colonists and mechanoids, with species exceptions configurable via [i]Configure animals fleeing from humans[/i].
Animals do not flee while hostile toward humans or when a pawn is attempting to tame them.
[img]https://i.ibb.co/1JrL0YNT/Chase-elephant.gif[/img]
[*] [b]Raiders ignore small pets[/b] — make raiders treat small, non-threatening pets (e.g., cats) like penned livestock unless they follow a master or go manhunter. [i]Enable raiders ignoring small pets[/i] and [i]Small Pet Body Size Threshold[/i] control this behavior; [i]Prevent small pets from melee attacking hostiles[/i] lets pets themselves react to raiders if desired.
[img]https://i.ibb.co/wrjwtFwm/Raiders-Ignore.gif[/img]
[*] [b]Predator protection of kills[/b] — predators may guard their kills against scavengers and colonists within a configurable [i]Prey protection range[/i] if [i]Enable predator defending their kills[/i] is enabled. The [i]protection-trigger size difference threshold[/i] prevents large predators from needlessly attacking minor scavengers.
[img]https://i.ibb.co/3YsfDp2m/Prey-Protection.gif[/img]
[*] [b]Scavenging[/b] — animals marked with [i]ModExtension_IsScavenger[/i] will eat rotten or even skeletonized corpses (with reduced nutrition) if [i]Enable scavenging (scavenger behavior)[/i] is enabled.
[img]https://i.ibb.co/TB48PStD/Scavengering.gif[/img]
[*] [b]Human bionics on animals[/b] — automatically enables many vanilla bionics on animals at runtime (excluding animals flagged [i]ModExtension_CannotBeAugmented[/i]) if [i]Enable human bionics on animals[/i] is enabled. Bionics scale with animal body size and apply appropriately scaled hediffs — useful for augmenting animals without installing separate augmentation mods; Combat Extended compatibility is preserved.
[img]https://i.ibb.co/4wjL9hCQ/2026-03-06-04-53-23.png[/img]
[*] [b]Aggro at slaughter[/b] — animals marked with [i]ModExtension_AgroAtSlaughter[/i] can become aggressive when slaughtering is attempted if [i]Enable aggro-at-slaughter[/i] is set to true. Downed animals may still be safely slaughtered.
[img]https://i.ibb.co/6088m53d/Aggro.gif[/img]
[*] [b]Mammal lactation & juvenile nursing[/b] — allows mammalian neonates to consume milk as their primary diet and gives mothers a lactation hediff that transfers nutrition to their young when [i]Enable mammals lactation[/i] is enabled. This is separate from vanilla milking mechanics. Animal offspring can follow their parents.
[img]https://i.ibb.co/gL8150qZ/Lactation.gif[/img]
[*] [b]Animal damage reduction[/b] — optionally reduces damage small animals inflict upon much larger animals (excluding genuine predator → prey interactions) if [i]Enable animal damage reduction[/i] is enabled, to avoid unrealistic rapid bleeding from tiny attackers. This option is disabled when Combat Extended is installed (CE handles realistic damage through armor and armor penetration).
[img]https://i.ibb.co/zhp6zK9V/2026-03-06-04-50-05.png[/img]
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Mod compatibility
[b]Zoology[/b] aims to be broadly compatible with most RimWorld mods. Most invasive behavior changes are optional and can be disabled in the mod settings if compatibility issues occur.
Explicit compatibility work has been done for multiple popular mods and frameworks.
For the full and continuously updated compatibility list, see the GitHub repository or the Steam Workshop discussions.
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[*] [b]Combat Extended[/b] — full compatibility. When CE is installed, animal damage, penetration, and defensive properties are recalculated using biological inputs such as hide thickness, claw and tooth length, and bite force. These are mapped onto CE formulas to produce more biologically grounded results.
An optional setting, [i]Override CE Penetration for animal life stages[/i], adjusts how body size influences penetration values so juvenile animals do not end up unrealistically lethal compared to smaller adult species.
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Planned future compatibility with other mods like Alpha Animals and Dinosauria (not currently included).
[b]Notes[/b]
No explicit conflicts are currently known. However, because Zoology recalculates stats for every animal and modifies certain behaviors at runtime, conflicts may occur with other mods that perform similar animal overhauls. Most behavior systems can be disabled in the settings to help avoid these conflicts.
Community & development
[b]GitHub repository:[/b]
[url=https%3A%2F%2Fgithub.com%2FAbobaShark%2FZoologyMod-Framework-For-Rimworld]https://github.com/AbobaShark/ZoologyMod-Framework-For-Rimworld[/url]
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