Fauna

Registers land animals from the base game and compatible mods with the Heartwood ecosystem platform. Adds habitat-aware populations, herding behavior, denning, and realistic life cycles.

Population Management

Habitat-Aware Spawning

Animals only appear in biomes that match their real-world habitat preferences. No more wolves in deserts or gazelles in tundra.

• Each species is mapped to specific habitat types (e.g., temperate forest, cold grassland)
• Population density scales with patch size and carrying capacity
• Seasonal presence modifiers — some species are less active in winter

Predator-Prey Dynamics

Predator populations are linked to prey availability. Wolves hunt deer and hares. Foxes target hares. Hyenas chase gazelles.

• Configurable prey species per predator
• Predation vulnerability varies by species (moose are harder to take down)
• Player hunting pressure tracked — overhunting depletes local populations

Breeding & Life Cycles

Animals age through visible stages, breed during specific seasons, and eventually die of old age.

• Four life stages: juvenile (50% size) → subadult (75%) → adult (100%) → elder (95%)
• Breeding months per species (e.g., wolves breed in late winter)
• Gestation periods and litter sizes (hares: 3–6, bears: 1–3)
• Juvenile mortality — not all offspring survive

Behavior

Herding

Social species form herds that move together across the landscape.

• Configurable herd sizes (deer: 3–8, gazelle: 5–20)
• Cohesion radius keeps herds grouped naturally
• Wander radius limits how far a herd roams from its home area
• Grazing behavior with randomized rest periods

Denning & Burrowing

Many species establish persistent homes in the world — visible dens and burrows that remain even when the animal is away.

• Dens — carved into hillsides for wolves, bears, foxes, hyenas, raccoons. Sized by species (1×1, 1×2, or 2×2 entrances)
• Burrows — dug underground for hares, chipmunks, field mice. Small 1×1 surface entrance
• Animals return home at night, during rain, or when injured
• Some species require a mate to establish a home (wolves)
• Homes take time to establish and decay if abandoned

Supported Species

Fauna registers 31 species across 2 mods. Species are only active when their source mod is installed.

Vanilla (23 species)

Herbivores

• Deer — temperate, cold, and warm variants (whitetail, caribou, chital, and more)
• Gazelle — arid grasslands and desert scrub
• Moose — cold forests and wetlands
• Sheep — temperate and cold grasslands (bighorn)
• Goat — temperate, cold, and warm variants (ibex, mountain goat, markhor)
• Pig — temperate and warm forests (wild boar, warthog)
• Hare — temperate, cold, and warm grasslands (with burrows)
• Chicken — temperate and warm grasslands
• Raccoon — temperate forests (with dens)

Predators

• Wolf — cold and temperate forests, pack dens, hunts deer/hares/sheep
• Bear — cold, temperate, and warm forests with 2×2 dens
• Fox — temperate and arctic variants, hunts hares
• Hyena — warm savannas, hunts deer/gazelle/hares

The Critter Pack (8 species)

• Chipmunk — forest floors (with burrows)
• Field Mouse — grassland burrower, fast breeder
• Squirrel — forest canopy
• Hedgehog — temperate woodlands
• Yak — cold herding species
• Crab, Snail, Isopod — aquatic and wet habitat species

Compatibility

Fauna does not add new entities. It registers existing animals from other mods with the Heartwood ecosystem and patches new behaviors and AI tasks onto them (herding, denning, lifecycle). Species from uninstalled mods are silently skipped.

Requirements

Vintage Story 1.22.0 or newer. Requires Heartwood.